August 2008 Archives

This Labor Day, Chicagoans should experience another nearly cloudless, warm,
low-humidity day with afternoon highs around 90 degrees. That's a reading 12 degrees
above normal for this date.
In the Great Lakes and Midwest, weather systems not only slow down but are starved of
potential moisture when hurricanes such as Gustav move out of the Gulf of Mexico and
strike the U.S. mainland.
Dry high pressure will continue to dominate northeast Illinois until Gustav moves
inland and allows some moisture to enter this area ahead of a cooling cold front
Wednesday. Temperatures the remainder of the week will be influenced by a
predominantly northeast flow that will keep highs in the 70s.
HANNA: U.S. LANDFALL STILL UNCERTAIN
With peak sustained winds of 50 m.p.h., Tropical Storm Hanna is approaching the
southern and central Bahamas.
It's still very early to determine the eventual movement of this storm as it approaches
the United States: Its potential landfall point ranges from the Florida panhandle to the
North Carolina coast.
Hanna is currently forecast to move northwest, paralleling the east coast of Florida and
intensifying to minimal hurricane strength by Thursday.
--By Paul Dailey, WGN Weather Center Meteorologist

Dear Tom,
Since hurricanes develop over saltwater oceans, does any of the rain come
down as salt water?
John
Dear John,
A raindrop is pure water (with the exception of the condensation nucleus
around which it initially formed and any pollutants such as smoke or
bacteria it might have picked up from the atmosphere). Rainwater is pure
because materials like salt dissolved in ocean water remain behind when
water evaporates from the ocean surface, and that's fortunate because sea
water contains a great deal of salt.
Herbert Swenson of the U.S. Geological Survey tells us ocean water contains
about 35 pounds of salt per 1,000 pounds of water. One inch of rain across
Chicago's 228.5 square miles of area yields 33.1 billion pounds of water. If
rainwater contained salt at the concentration of ocean water, 1.2 billion
pounds of salt would accompany every one-inch rain across the city.

As August draws to a close, late-season warmth is taking up residence in the Chicago
area and should stick around at least through midweek. With the Central U.S. weather
system slowed to a crawl as two powerhouse tropical systems, Gustav and Hanna,
approach the U.S. mainland, persistent high pressure will bring warm and increasingly
hazy and humid weather to the city. Readings should climb to the middle and upper 80s
through midweek. If the mercury reaches 89 degrees Monday, it would mark the city's
warmest Labor Day since 1983, when the high reached a sizzling 95 degrees.

KILLER GUSTAV BATTERS CUBA, GULF COAST NEXT

Packing sustained winds of 150 m.p.h., Hurricane Gustav, already responsible for more
than 80 deaths in the Caribbean, slammed western Cuba, including the capital city of
Havana, Saturday afternoon. As the storm prepared to enter the Gulf of Mexico,
hurricane watches were posted from just east of Houston to the Alabama-Florida
border in anticipation of a Labor Day landfall. Wind gusts to nearly 60 m.p.h. were
recorded in the Florida Keys Saturday afternoon as Gustav's outer bands swept through
the area.

--Steve Kahn, Meteorologist, WGN-TV/Chicago Tribune

Dear Tom,

What constitutes a sunny day?
How many sunny days a year does Chicago get as compared to southeast Florida?
Mike Priory, Ft. Lauderdale

Dear Mike,
We checked with Chicago climatologist Frank Wachowski, who maintains Chicago’s
sunshine records, and he told us that while the definition is somewhat subjective, he
considers a day to be sunny if it has less than three-tenths cloud cover in daylight and
records 90 percent or more of the possible sunshine. Believe it or not, Chicago averages
83 sunny days a year, compared with only 74 in southeast Florida, a result of the almost
daily clouds that form in the tropical Florida air masses. However, a more realistic
comparison would be in percent of possible sunshine, and southeast Florida wins that
hands down, logging around 70 percent annually compared with Chicago’s 54 percent.

With just two days remaining in the month, August 2008 has hosted 77 percent of its
possible sunshine -- the second consecutive month this summer to do so. It's a
sunshine tally well above the 66 percent average and far ahead of last year's 57 percent.
It becomes the sunniest August to occur here in 22 years, and this weekend's sunny
weather is likely to make it the sunniest in 25 years by the time the books close at
midnight Sunday.
Chicago's official rainfall has been a fraction of last August's: 3.73 inches vs. 9.70
inches. Rain has fallen less than a third as frequently (five days vs. 16) in August
compared to a year ago. It's a far cry from the rainy manner the three-month June, July
and August meteorological summer period began. Rain isn't predicted here until the
middle of the week at the earliest.

GUSTAV MOVING OVER DEEP, WARM WATERS AND EXPECTED TO INTENSIFY
Nervous Gulf Coast residents are watching Hurricane Gustav, currently packing 80
m.p.h. top winds as it approaches the warm, deep waters between Cuba and the
Yucatan Peninsula where it is expected to become a major hurricane with winds in
excess of 110 m.p.h.
--Tom Skilling, Chief Meteorologist, WGN-TV/Chicago Tribune

Dear Tom,
Has a Gulf of Mexico hurricane ever crossed Mexico and entered the Pacific?
If it did would it keep the same name?
Charles Schmitz, Burbank
Dear Charles,
It doesn't happen often, but since the advent of weather satellites in the
1960s there have been at least eight documented cases where a tropical
cyclone has traveled from the Gulf or Caribbean into the Pacific or
vice-versa. When this does occur, the storm is renamed with the next name on
the new basin's list. In 1996, Atlantic Hurricane Cesar became Pacific
Hurricane Douglas after crossing southern Nicaragua. In similar fashion,
Tropical Storm Bret became Hurricane Greg when it entered the Pacific in
1993. In 1989 Hurricane Cosme changed gender and became Tropical Storm
Allison after it survived a trip across Mexico and moved into the Gulf of
Mexico, eventually making a Texas landfall south of Houston.

Spectacular Labor Day weekend weather awaits Chicagoans. The 50,000-foot tall
thunderstorms, which treated Downstate Illinois residents to spectacular lightning
displays while bypassing much of the Chicago area late Thursday, deposited
downpours of 3 to 4 inches and have moved on. Rain-free weather is predicted well
into Tuesday. The air mass responsible is to stall in coming days as air, vented out the
top of intensifying Hurricane Gustav -- expected to traverse the Gulf of Mexico this
weekend -- migrates away from the storm then sinks, warms and dries over much of
the eastern U.S. It's a process likely to strengthen and slow the warm air dome allowing
to it slowly stagnate here. The light, disorganized surface winds within will facilitate a
slow build-up of haze, which should become a little more evident each of the coming
three days.

The Labor Day holiday, accepted by many as an unofficial close of the summer season,
is no stranger to warm, dry weather in Chicago. Of the past 114 Labor Days, 64 have
been rain-free.

SHORTER DAYS, LESS INTENSE SUN MAKE LATE SEASON 'HEAT' MORE TOLERABLE

Readings flirt with 90 degrees inland Sunday and Monday. But humidities are to remain
low until the middle of next week.

--Tom Skilling, Chief Meteorologist, WGN-TV/Chicago Tribune

Dear Tom,

Gustav is heading toward the U.S. with Hanna following. Have two tropical cyclones
have ever run into each other?

Bob Freed Naperville

Dear Bob,

When two tropical cyclones get close to each other (less than a thousand miles), they
do not collide, but rather rotate around each other cyclonically (counterclockwise in the
Northern Hemisphere), a result of the Fujiwhara effect. This motion is named after the
Japanese meteorologist Sakuhei Fujiwhara who described it in a 1921 paper dealing

with the motion of whirls in water. A classic example of the Fujiwhara effect took place
in August 1995 when Tropical Storm Iris was interacting with Hurricane Humberto. With
time, the storms often drift apart and move their separate ways, but if one is
significantly stronger it may eventually absorb the other storm into its circulation.

In tonight's Before the Forecast, Tom fills us in on what we can expect for the holiday weekend -- including perhaps daytime temperatures nearing the 90s.

Find out the full scope for this weekend a day early, in this Thursday edition of BTF!

For complete weather information, tune in to WGN News at 9pm and wgntv.com for Tom Skilling's Full and 7-day forecasts.

Tune in tomorrow for another edition of Before the Forecast, and as always continue
to watch WGN for more coverage: Morning, Noon & Nine.

It was 18 years ago when 90-degree heat in combination with stifling humidities --
including tropical rain-forest level 80-degree dew points -- tangled with a cold front
and abnormally strong upper level winds to produce one of the Chicago area's deadliest
tornadoes in southwest suburban Plainfield. The storm, which hit around 3:50 p.m.,
claimed 29 lives and injured hundreds.

The weather is far more tranquil as Thursday dawns. However, thunderstorms threaten
as humid air surges back into area for the first time in five days this afternoon and into
early night. Rainfall produced by these storms will be welcome -- much of the area has
had little rain for nearly three weeks.

Wednesday's 83-degree high marked the 66th reading at or above 80 degrees this year.
Weather records indicate the area's final 80-degree day is still more than month away.

GUSTAV HAS GULF COAST ON EDGE

Residents of the Gulf Coast are understandably nervous as Tropical Storm Gustav --
weakened by its interaction with Haiti on Wednesday -- churns toward the Gulf, where
it threatens to become a major hurricane.

--Tom Skilling, Chief Meteorologist, WGN-TV/Chicago Tribune

Dear Tom,

Has a tropical storm's name ever been retired?
Tom Urban Oak Park

Dear Tom,
It's happened only once and that was Tropical Storm Allison, which made landfall near
Houston on June 5, 2001. Though never achieving hurricane status, Allison, with top
winds of only 58 m.p.h., was a slow-moving and prolific rainmaker much like recent
Tropical Storm Fay. The storm brought more than 36 inches of rain to the Houston area
as it meandered for days along the northeast Texas coast. After drowning Texas,
Allison's heavy rains tracked across the Gulf Coast region and then turned northeast
into southern New England and the Canadian Maritimes. It finally headed out into the
Atlantic on June 18.

In addition to catastrophic flooding, Allison produced 23 tornadoes and was
responsible for at least 50 deaths and $3 billion in property damage.

Thanks for joining us for this Wednesday edition of Before the Forecast!

For complete weather information, tune in to WGN News at 9pm and wgntv.com for Tom Skilling's Full and 7-day forecasts.

Tune in tomorrow for another edition of Before the Forecast, and as always continue
to watch WGN for more coverage: Morning, Noon & Nine.

This year's dry August weather is a stunning change from a year ago. Just 0.15 of an
inch has fallen at O'Hare in the 22 days since Aug. 5. That's just 5 percent of the
long-term average, and the driest Aug. 5-27 since the 0.14 of an inch fell in that period
in 1963. It's little wonder lawns are looking brown and area farmers are contemplating
spraying fields to counter a build-up of insects attracted to the dry weather. The
Chicago area had been doused by 9.67 inches in the same period a year ago -- 64
times as much rain! What a difference a year makes!

The dry weather increases the importance of any thunderstorms which erupt Thursday
or Thursday night. But those storms won't affect all areas -- just 30 to 50 percent of
the area may see a storm.

GUSTAV LURCHES TOWARD GULF

Hurricane Gustav threatens to travel over the Gulf of Mexico's infamous Loop Current
once clearing the Caribbean in coming days. That's an ominous development. Warm
water runs more than 2,000 feet deep in that region. It has fueled explosive
intensification in storms like Katrina in the past and threatens to turn Gustav into a
powerhouse storm with potential 100+ m.p.h. winds -- the season's strongest yet.

--Tom Skilling, Chief Meteorologist, WGN-TV/Chicago Tribune

Hi Tom,

My wife and I are having a disagreement as to what comes first: thunder or lightning.
There is a lot riding on your answer.

-Bill & Maureen Lahtinen, Elk Grove Village, Ill.

Dear Bill and Maureen,

Lightning always occurs first -- always -- because lightning causes thunder. The
electric spark that constitutes a lightning bolt heats the air through which it passes to
at least 50,000 degrees in thousandths of a second. Explosive expansion of the air
immediately occurs, followed by cooling and sudden contraction. These events trigger
waves in the air which we interpret as thunder. The initial thunder that you hear comes
from the point on the lightning channel closest to you; the last sound comes from the
most distant point.

It will be difficult, probably impossible, to pair each lightning discharge with the
thunder that it produces when an active thunderstorm is generating very frequent
lightning strokes.

Thanks for joining us for this Tuesday edition of Before the Forecast!

For complete weather information, tune in to WGN News at 9pm and wgntv.com for Tom Skilling's Full and 7-day forecasts.

Tune in tomorrow for another edition of Before the Forecast, and as always continue
to watch WGN for more coverage: Morning, Noon & Nine.

Diane Frank’s brother was out doing yard work at his home in Parker, Colorado Sunday
when this twister appeared. Thanks for bringing these photos to our attention,
Diana—and thank your brother for taking them. They’re fascinating!

Tom Skilling

Photos courtesy of Diane Frank

It’s always wonderful to open Mark Vogan’s e-mails from the UK because they so often
include spectacular shots of that beautiful part of the world and the weather which is
going on there. Mark and his wife Karen have traveled in recent days from Scotland to
London and then on to Dover, site of the Channel Tunnel beneath the English Channel
which links the UK with the European continent. Check out his photos! Mark tells us
the weather has been clear and warm with daytime readings near 70-degrees. He
comments that the waters of the English Channel the day he Karen visited the area had
taken on the appearance of Caribbean or Mediterannean waters because of their light
blue hue. Many thanks Mark for taking the time to share these photos with us!

-Tom Skilling

Photos courtesy of Mark Vogan in the UK

The Farmer's Almanac -- always a fun read but an anathema to long-range forecasters
in the meteorological and climate communities -- is out with a forecast of a cold,
snowy winter ahead. It's a prediction at odds with the outlook for Winter 2008-09
produced by NOAA forecasters who project above normal temperatures and near
normal precipitation. We've been doing our own research on winters that have followed
summers with few 90s and looked at winters between El NiÒos and La NiÒas -- 27 of
them since 1950 -- because computer projections of equatorial Pacific conditions
predict that's what's ahead. Among our findings: These winters can be volatile, some
featuring large temperature swings as arctic and Pacific air duel it out. While the
number of warmer and colder than normal winters were nearly equal in these years,
there was a discernible trend for the cold winters to be significantly colder than normal.
By contrast, mild winters tended to by only modestly milder than normal. The
temperatures of all 27 winters averaged more than 1-degree below normal. The split
between snowy and not-so-snowy winters was nearly even. While full-season snowfall
averaged out near the Chicago average of 38.6 inches, winters with big snows had
some really big snows: among them 89.7 inches (1978-79).

--Tom Skilling, Chief Meteorologist, WGN-TV/Chicago Tribune

Dear Tom,

As summer begins to wind down, when can we expect our first high temperatures
below 70 degrees? How about back-to-back days of sub-70-degree highs?
-Matt Balitewicz, East Chicago, Indiana

Dear Matt,

A few "cool" summer days (defined as days whose maximum temperature fails to break
out of the 60s) occur all through the summer, but not very often.

A scan of 80 years of daily highs registered at Midway Airport during the last week of
July and first week of August indicates that sub-70-degree highs occurred only 19
times, or one day out of 59. That frequency increases to one day out of 28 at the end of
August and one out of two by the end of September. The average date of the city's first
sub-70 day in the autumn is Sept. 10, and the first back-to-back sub-70 days can be
expected a week later, Sept. 16-17. A string of three such days is likely by Sept. 22-24.

David Gotfryd, a sophomore at Batavia High School, is good enough to share HIS photo
of the eye-catching post-sunset shadows as viewed from the Fox Valley. It’s clear from
the number of responses we’ve received from many of you that THIS was a phenomenon
which captured the attention of many all across our region. MANY THANKS David. He
tells us he and his dad attended and enjoyed last spring’s Fermilab Tornado and Severe
Storms Seminar. That’s wonderful news, David and we hope you can join us again next
April at our 29th annual Fermilab Tornado seminar. No date yet—but we’ll work on
getting that out to all interested in the next few months.

Tom Skilling


Photo courtesy: David Gotfryd, Batavia, Illinois

Thanks for joining us for this Monday edition of Before the Forecast!

For complete weather information, tune in to WGN News at 9pm and wgntv.com for Tom Skilling's Full and 7-day forecasts.

Tune in tomorrow for another edition of Before the Forecast, and as always continue
to watch WGN for more coverage: Morning, Noon & Nine.

Aaron Henkleman snapped this photo Saturday evening, which captures the same
optical phenomenon brought to our attention by Jeff Chochola, who observed a virtually
similar display just a night earlier. Aaron’s photo was taken as he fished on Spin Lake
west of Danvers in downstate Illinois just west of Bloomington! Aaron correctly
speculated in his e-mail to us that the distant tops of cumulonimbus clouds might be
playing a role here. That’s exactly what was going on.

THANKS Aaron for the great photo!

Tom Skilling


Photo courtesy of Aaron Henkleman, Danvers, Illinois

“What caused this blue band at sunset this past Friday, August 22?”
asks Jeff Chochola, who sent us this photo.

Jeff, it’s likely the tops of towering cumulonimbus clouds (distant thunderstorms) are
behind what you see here. The dark bands here likely resulted when sunlight was
blocked by the tops of these clouds. With the disc of the sun below the horizon, the
only sunlight arriving was above ground level. Shadows were being on the high cloud
deck visible here by the distant cumulonimbi. Neat effect, isn’t it?? THANKS Jeff for
taking the time to share this with us!

-Tom Skilling

Photo courtesy of Jeff Chochola

Mike Toohill, who does such a great job of keeping us posted on the condition of Illinois
crops downstate, relays this shot of the dry weather’s effect on corn in the light soils of
central Illinois. Mike also caught hot air balloons just above the horizon near Lincoln,
Illinois Saturday morning. Thanks for the great shots, Mike!

Tom Skilling

Photos courtesy of Mike Toohill

With just a week left in meteorological summer, Chicago along with much of the
Midwest is locked in a comfortable autumnal-like air mass.
Record lows toppled Sunday morning when the mercury dipped to 39 degrees at Grand
Forks, N.D., and 50 degrees at Marshalltown, Iowa. Frost and freeze conditions are
expected Monday morning in portions of the Upper Midwest.
In Chicago, Sunday's high at Midway Airport reached only 78 degrees, a drop of 12
degrees after Saturday's rare 90 -- only the eighth of the year. Officially the city has
logged only three 90s at O'Hare Airport with none since mid-July. Rockford has failed
to record a single 90 so far in 2008, something that has never happened there since
records began in 1893.
Temperatures here will creep back into the 80s later this week as warmer and more
humid conditions stage a brief return.

TWISTERS SIGHTED SOUTHEAST
OF DENVER AND IN ALABAMA
Severe thunderstorms erupted along the foothills of the Rockies southeast of Denver
Sunday evening. A large, long-lived twister was sighted near Parker.
In central Alabama, Fay's remnants spawned two twisters: one near Emerald Mountain
and the other near Welona.
--By Steve Kahn, WGN Weather Center Meteorologist

Dear Tom,
Please refresh our memories of the August 1987 flood.
Thanks, Larry
Dear Larry,
August 1987 had opened hot and dry in Chicago, and vegetation was stressed
from the lack of rain. With a front setting up west of the city on Aug. 13,
forecasters were hopeful for some much-needed rain. Well, the rains came,
but unfortunately they didn't stop. Torrential downpours descended upon the
Chicago region as repeat waves of thunderstorms "trained" over areas from
Rockford to Chicago's North Side. When the rains finally ended more than 17
hours later, 9.35 inches of rain had inundated the O'Hare area, making it an
inaccessible island for nearly 24 hours. Three people died and flood damage
exceeded $220 million. The wet weather continued, and by the end of the
month O'Hare had logged 17.10 inches of rain, making August 1987 the city's
wettest month on record.

Canadian high pressure centered over the northern Great Lakes will be responsible for
nearly clear skies, lowering humidities and cooler temperatures over Wisconsin, much of
Illinois and Indiana early this week. As the center of the high pressure system tracks east,
clouds will slowly increase over Chicago midweek ahead of an approaching cold front that
should bring much higher humidities and a period of showers and t-storms Thursday.

MISSISSIPPI TO BE NEXT HOME FOR FAY

As winds weaken over land, Fay will lose its tropical storm title later today, but the low
pressure system will continue to dump copious rains over the southeastern U.S. as its
center drifts almost aimlessly over Mississippi until finally being absorbed into the
late-week cold front. Incredibly heavy rains from 15 to well more than 20 inches were
reported over the Florida Panhandle Saturday, and anywhere from 10-to-20 inch totals are
expected along, and a couple hundred miles on either side of, its meandering path by
week’s end.

Dear Tom,
Why did the winds of Hurricane Fay increase while the storm was over land? I thought
hurricanes dissipated when they move over land.
William Brown, Chicago

Dear William,
Fay's sustained winds topped out at 60-65 m.p.h., below minimum hurricane strength of
74 m.p.h., and so Fay spent her life as a tropical storm (sustained winds 39-73 m.p.h.).
However, you are correct to state that hurricanes and tropical storms weaken and
eventually dissipate over land. The weather sometimes breaks the rules, if only briefly,
and Fay’s highest winds did, indeed, occur after the storm moved inland. After landfall,
conditions in the upper atmosphere (generally above 30,000 feet) became more favorable
for "ventilation"--dispersion away from the top of the storm of air rising through the body
of the storm—and Fay's winds strengthened 5-10 m.p.h to 60-65 m.p.h.

Thanks for joining us for this Friday edition of Before the Forecast!

For complete weather information, tune in to WGN News at 9pm and wgntv.com for Tom Skilling's Full and 7-day forecasts.

Tune in tomorrow for another edition of Before the Forecast, and as always continue
to watch WGN for more coverage: Morning, Noon & Nine.

This second-to-last weekend of meteorological summer promises Chicagoans warm
and muggy weather with many rain-free hours. But the atmosphere is saturated with
moisture -- nearly 2 inches of it. With converging winds predicted this afternoon in
advance of an approaching cold front -- a set-up which generates a build-up of
moisture known as dew point pooling -- thunderstorm development is likely.
The manner in which Friday's thundery rains hit the area -- fast and, in terms of areal
coverage, selectively -- is instructive. Portions of the Chicago metro area may see
gusty downpours Saturday while other areas end up largely rain-free.

DESPITE LACK OF 90S, SUMMER RANKS AMONG WARMEST 33% HERE SINCE 1871
With only nine days left in meterological summer, Chicago's 72.5-degree average
temperature since June 1 ranks 46th warmest since 1871; that's among the warmest 33
percent of all years on record.
The relatively warm summer has occurred despite the lack of 90-degree-plus
temperatures. To date, only three 90s have occurred at the official observation site at
O'Hare Inernational Airport. A typical year sees 17 such days there.
--Tom Skilling, Chief Meteorologist, WGN-TV/Chicago Tribune

Dear Tom,
Forecasters keep talking about how many hurricanes we've had, citing how the
list of names was exhausted in 2005. I remember that they only used to name
hurricanes and not tropical storms when I was a girl (many years ago). When
did they start naming tropical storms?
Pam from Hinsdale
Dear Pam,
The practice of naming Atlantic Basin tropical cyclones started in 1950 with
the use of the phonetic alphabet (Able, Baker, Charlie, etc.), then switched
to all female names in 1953 and finally to alternating male and female names
in 1979, a practice still followed today. From the very start, both tropical
storms and hurricanes were given names, but in checking the list of storm
names from the 1950s and '60s we noticed several storms that were assigned
numbers rather than names for a variety of reasons, and this may well be
what you are remembering.

It hasn't been this muggy in Chicago in 17 days. Friday's southerly winds deliver air
dripping with nearly 2 inches of evaporated moisture with origins over the mid- and
upper-80 degree waters of the Gulf of Mexico. August hasn't lived up to its
climatological history as the city's wettest and second most humid month. The last
measurable rain fell a week ago -- but the last downpour-generating storms hit nearly
three weeks ago, on Aug. 4. The last 17 days have hosted only 0.06 inches of rain. The
northward rush of humid air Thursday led to eruption of scattered though impressive
thunderstorms to Chicago's south and west. Late-day Doppler radar scanned cloud
tops as high as 41,000 feet and estimated rainfall in harder hit locations just 90 miles
southwest of Chicago at 1.50 inches.

FAY'S HISTORIC RAINS NOT HISTORY YET; DELUGE SHIFTING WEST AND NORTH, AND MOVING SLOWLY

Sections of central Florida were reeling from a second day of downpours from stalled
Tropical Storm Fay. Just shy of 30 inches of rain fell in the Melbourne area. Cape
Canaveral recorded nearly 9 inches Thursday. The storm's impact is far from over. The
slow west/northwest drift threatens to spread torrential rains north into southern
Georgia and Alabama.

--Tom Skilling, Chief Meteorologist, WGN-TV/Chicago Tribune

Dear Tom,
In July, 1943 I was on a troop train from traveling from Atlanta into Missouri. One
morning the train was traveling very slowly and we could see nothing but water. Was
there flooding in the Midwest that summer?

Don Willing Thornton, Ill.

Dear Don,
In late spring and early summer of 1943 much of the Midwest was besieged by repeat
bouts of heavy rainfall. Major flooding followed on many of the region's rivers including
the Mississippi, Missouri, Arkansas, Illinois and Wabash, leaving hundreds of
thousands of acres of farmland under water. Some of the worst conditions were in the
St. Louis area near the confluence of the flood-swollen Missouri and Mississippi rivers,
where thousands of people were stranded. Precipitation totals were impressive. In June,
1943 St. Joseph, Missouri was swamped by nearly 16 inches of rain while nearby
Maryville received nearly 13.5 inches.

There have been a few technical difficulties today with our webcam, so sadly there's no Before the Forecast tonight, but we hope to be back first thing tomorrow for a week's end edition of Before the Forecast!

For complete weather information, tune in to WGN News at 9pm and wgntv.com for Tom Skilling's Full and 7-day forecasts.

Tune in tomorrow for another edition of Before the Forecast, and as always continue
to watch WGN for more coverage: Morning, Noon & Nine.

Our friend and frequent photo contributor Mike Frankowski has sent us these spectacular
shots of Wednesday evening’s sunset in the South Elgin area! Thanks Frank!

Tom Skilling

Photos courtesy of Mike Frankowski, South Elgin

Thanks to Anson Mount for giving us this glimpse of Thursday morning's sunrise over Waukegan!

-Tom Skilling

Photo courtesy of Anson Mount

Rain has been in remarkably short supply in recent weeks -- hardly enough to keep up
with the 1.40 inches of water lost each week to evaporation in the warm August sun.
The last measurable rain to fall here was the 0.06 inches at O'Hare on Aug. 13. Truly
significant rain has been absent even longer. It was almost three weeks ago that a
lightning-laced thunderstorm complex unleashed driving downpours here totaling 2.43
inches at O'Hare.

Increasingly moist air will lead to noticeably higher humidities in coming days and
growing prospects that scattered thunderstorms will occur. Upper winds are to remain
comparatively light as the air's moisture content surges to nearly 2 inches. This means
any thunderstorms that develop may be capable of some heavy downpours --
especially Friday and Friday night then again later Saturday or Saturday night. Things
should dry out Sunday.

MORE RAIN FROM FAY IN MELBOURNE, FLA. THAN IN 2 HURRICANES IN 2004

Central Florida is reeling after rain of historic proportions associated with Tropical
Storm Fay. More rain has fallen in east central Florida -- 17.63" at the National Weather
Service Office in Melbourne in recent days -- than fell there in two 2004 hurricanes --
Frances and Jeanne.

--Tom Skilling, Chief Meteorologist, WGN-TV/Chicago Tribune

Dear Tom,

How far north has a hurricane ever moved? Has one ever reached Canada?
Nick Recchia, River Grove, Ill.

Dear Nick,

It happens about once every four years, and here are two of the worst.

On Sept. 9, 1775, a northward-bound hurricane swept across the Newfoundland Banks
off Canada's eastern maritime provinces, drowning 4,000 sailors. But that was not a
land-falling storm.

Hurricane Hazel was.

Formed near the tropical island of Grenada on Oct. 5, 1954, Hazel trekked northward
across Haiti (1,000 deaths) and the Bahamas (six deaths), making landfall in North
Carolina (19 deaths) with 130 m.p.h. winds. Hazel then blasted 600 miles overland,
bringing 11 inches of rain and 80-m.p.h. winds to Toronto, Canada, claiming 81 lives.
The storm continued northeast as a vigorous low pressure system, crossing the North
Atlantic Ocean and the Arctic Circle, eventually dissipating over Scandinavia.

In tonight's Before the Forecast, find out the latest on the enduring weather developments of Tropical Storm Fay. The storm's heavy rains and winds continue to pound Florida, including reports of 24.8 inches of rain. The consensus is that it's moving toward southern Alabama -- but you'll want to watch the full edition of BTF to see what the models say about Fay's impact.

For the complete weather information, tune in to WGN News at 9pm for Tom Skilling's Full and 7-day forecasts.

Tune in tomorrow for another edition of Before the Forecast, and as always continue
to watch WGN for more coverage: Morning, Noon & Nine.

Despite the brief chill at this point in the month a year ago, August is running more
than three degrees cooler this year. Even though August 2007 highs failed to reach 70
degrees on both the 18th and 19th, last summer had managed its fair share of hot
temperatures, having produced 14 days of 90-degree readings. The city a year ago
today was just two days away from a 15th day at or above 90 degrees.

The comfortable weather here Tuesday extends into a second day Wednesday, driven in
part by northeast winds off a sprawling area of high pressure centered over the Great
Lakes. The inland-moving northeast flow Tuesday provoked a few isolated
thunderstorms in Chicago's far western suburbs and in sections of northern Indiana.
DeKalb recorded 0.08 inches of rain in the storms .

TROPICAL STORM FAY DRENCHES FLORIDA WITH UP TO 10 INCHES OF WIND-DRIVEN RAIN, SEVEN TWISTERS TUESDAY

With the concern over flooding growing as Tropical Storm Fay moves off the Florida
peninsula Wednesday, where it is to tap energy and moisture off warm Atlantic waters,
residents are reeling after a day of downpours and twisters Tuesday. More than 9 inches
of rain fell near Jensen Beach on Florida's east coast.

--Tom Skilling, Chief Meteorologist, WGN-TV/Chicago Tribune

Dear Tom:

Tornado warnings always include the admonition to stay indoors, away from windows. I
don't understand this because such storms create low pressure outside buildings that
would cause windows to blow out, with no harm from breaking glass to the building's
occupants.

Charles Stewart, Gladstone, Mich.

Dear Charles,

It was once believed a sudden large reduction in air pressure in tornadoes caused
windows and even entire buildings to "explode" outward. But newer information gleaned
from analyses of videos of tornadoes actually destroying buildings and from
wind-tunnel tests that simulate tornadic conditions give no evidence of such
explosions.

We now understand that tornadic winds can penetrate buildings. Windows often shatter
inward, spraying rooms with deadly shards of glass. In fact, flying debris in the primary
cause of death and injury during tornadoes.

We start off today's Before the Forecast with a small correction. We accidentally said today's date is August 20th, but today is actually August 19. Our apologies for the error, and we hope you enjoy today's August 19th edition of Before the Forecast!

Today Tom covers the storms forming to the West of us, and also the latest developments with tropical storm Fay. Find out what's in store for Chicago weather in the next few days and whether we should be gearing up for some passing thunder.

For the complete weather information, tune in to WGN News at 9pm for Tom Skilling's Full and 7-day forecasts.

Tune in tomorrow for another edition of Before the Forecast, and as always continue
to watch WGN for more coverage: Morning, Noon & Nine.

Chicagoans are accustomed to most of their fronts and weather systems arriving from
the west. But sometimes a "back door" cold front -- one which slides across the area
from the northeast -- visits the area. Tuesday is such an occasion. The front's passage
briefly checks the string of slow but steady daily temperature increases under way here
since Saturday. Strengthening northeast winds behind the front Tuesday will lower
temperatures over much of the area into the 70s. An isolated shower or thunderstorm
may develop in a few spots west and south of the city as the gusty northeast winds
converge with slower moving air. It's a setup that forces air to rise, cool and condense.

Noticeably muggy air won't be absent long. Resurging warmth and humidity as early as
Thursday afternoon threatens to ignite clusters of thunderstorms while boosting
temperatures late this week.

WINDY POST-FRONTAL TEMPERATURE DIVE TAKES GREEN BAY FROM YEAR'S FIRST 90 TO 75 DEGREES IN AN HOUR

Temps in Green Bay went into a tailspin Monday evening as the back-door front visiting
Chicago on Tuesday passed. Readings there fell from 90 degrees -- the first 90s there
in 2008 -- to 75 in an hour. Northeast winds gusted to 31 m.p.h.

--Tom Skilling, Chief Meteorologist, WGN-TV/Chicago Tribune

Dear Tom,
Twenty-five years ago I was caught out on Lake Michigan in a terrible storm. The storm
took off roofs and capsized dozens of boats. What information do you have on this
storm?

Ralph Bassett, Wilmette

Dear Ralph,

The storm that you remember struck during the evening hours of July 19, 1983, with
wind gusts clocked as high as 87 m.p.h. at far northwest suburban Woodstock. The
storm produced an extensive swath of damage to buildings, trees and power lines. Nine
planes were overturned at DuPage Airport, and a 50 foot luxury cruiser moored at Navy
Pier sank during the storm. The fast-moving storm produced a seiche on the lake
resulting in a rapid fluctuation of water levels along the Chicago shore. Wind clocked in
the city were not quite as strong, reaching 69 m.p.h. at O'Hare International Airport and
55 m.p.h. at Midway. Temperatures crashed in the wake of the storm dropping from 81
to 69 degrees in less than an hour.

Thanks for joining us for Before the Forecast on August 18, 2008. In this edition, Tom fills us in on tropical storm Fay with its high winds and intense rains. Check out the maps for an in-depth look at the weather situation in Florida.

For the complete weather information, tune in to WGN News at 9pm for Tom Skilling's Full and 7-day forecasts.

Tune in tomorrow for another edition of Before the Forecast, and as always continue
to watch WGN for more coverage: Morning, Noon & Nine.

After an auspiciously wet start, August has turned dry in the Chicago area. With nearly
3.5 inches logged in the city's official rain gauge at O'Hare International Airport
through Aug. 4, the city seemed well on its way to blow away the month's normal
4.62-inch rainfall total. However, since then, the rain spigot has abruptly turned off
with only a meager 0.06 inches on the books in the last two weeks.
Rain does not appear to be in the cards here until late Thursday, when tropical moisture
surges into the area. Should the remnants of Fay pass close to Chicago as indicated by
some computer models, the city could be in line for a resurgence of precipitation by
next weekend.

FAY'S TRACK, STRENGTH STILL IN DOUBT
As Tropical Storm Fay prepares to cross western Cuba and head into the eastern Gulf of
Mexico, its track and intensity are still in question. Fay, already responsible for five
deaths in Hispaniola, is expected to reach hurricane strength after crossing Cuba and
energizing on the bathtub-warm waters of the eastern Gulf of Mexico as it heads
toward the United States. Florida still appears a likely landfall target with hurricane
watches posted through the Keys and along much of the state's west coast.
--By Steve Kahn, WGN Weather Center Meteorologist

Dear Tom,
I flew in World War II, and we often saw lightning hit the aircraft and
dance along the leading edge of the wings. We called it St. Vitus dance. Who
was St. Vitus?
Chester Sowinski, Wheaton
Dear Chester,
St. Vitus is the patron saint of actors and dancers, but he is also said to
protect against lightning. However, the phenomenon that you observed is more
commonly called St. Elmo's fire -- a corona or point discharge that occurs
when the environmental electrical field is high, especially on pointed
objects such as lightning rods, chimneys and airplane wings. The electrical
charge on the pointed surfaces can be as much as 10,000 times stronger than
in nearby open locations, causing the air to ionize and produce a luminous,
usually bluish glow. Sailors observed this atop ships' masts and named it
St. Elmo's fire after St, Erasmus, the patron saint of sailors.

After six straight days with highs in the 70s, summertime 80s are back in Chicago.
Readings broke the 80-degree mark Saturday for the first time since Aug. 9 marking the
start of a warmer and eventually more humid air flow into the Midwest.

More clouds and a small chance of thunderstorms may detract from Sunday’s Air &
Water show after nearly cloudless skies and unlimited visibilities highlighted the show’s
first two days.

More thunderstorms are possible later in the week and on the weekend as a continuing
southerly flow of air feeds moisture into the region.

The increase in cloudiness along with periodic showers and thunderstorms should put a
cap on temperatures, holding afternoon highs below the 90-degree mark.

STRENGTHENING TROPICAL STORM FAY APPEARS TO BE FLORIDA-BOUND

Tropical Storm Fay, the season’s sixth named storm in the Atlantic, now packing top
winds of 45 m.p.h. , is expected to become a hurricane after crossing western Cuba on
Monday. Latest computer guidance brings the storm into the far eastern Gulf of Mexico
as it heads for a possible Florida Gulf Coast landfall on Tuesday afternoon.

Dear Tom,
I regularly see Stanley, Idaho, listed as the coldest spot in the nation. Why is Stanley so
cold?
-Jim Kautz, Geneva

Dear Jim,
Stanley, Idaho, is a frequent winner in the "coldest in the nation" sweepstakes. This
small, picturesque town in the southcentral portion of the state is about 130 miles
northeast of Boise. The official thermometer is 2 miles east of town at an elevation of
6,495 feet. Stanley's infamous low temperatures can be attributed to the town's position
beneath the 12,000-foot snowcapped peaks of the Sawtooth and White Cloud
Mountains. Dense cold air descends from those peaks into the valley around Stanley,
prompting the very chilly readings. While many of Stanley's national lows occur in
summer, it also gets frigid in winter, with that location's all-time record low of 54
degrees below zero on Dec. 23, 1983.

Skies above Chicago Friday evening included the nearly full moon and, as Norma
Saldana of Rogers Park discovered, meteors too. While looking out over Lake Michigan,
she spotted four of them. The Perseids meteor shower, which peaked earlier this week,
may produce sightings in the Chicago area the next few nights.
The Chicago Air and Water Show opened with perfect weather Friday. The day's
78-degree high marked the area's sixth consecutive day of 70-degree temperatures --
something which last happened in August's opening two weeks 34 years ago. Only one
in five Augusts since 1928 has produced six-day strings of 70s.
New York City was placed under a tornado warning Friday, an uncommon event.
Doppler radar had indicated a circulation in thunderstorms sweeping the area. The
storms downed trees and power lines and produced structural damage. Weather Service
personnel will investigate a possible tornado touchdown near the border of the Bronx
and Westchester County Saturday.

AFTER SUMMER DOMINATED BY 90s, DENVER SHIVERS IN 50s
Snow appeared Friday near Colorado's Eisenhower Tunnel as Denver residents endured
rain and 50-degree temperatures.
--Tom Skilling, Chief Meteorologist, WGN-TV/Chicago Tribune

Dear Mr. Skilling,
What kind of hurricane season is expected?
Roger Smolich
Dear Roger,
The National Weather Service's Climate Prediction Center (CPC) released its
updated outlook for the 2008 hurricane season on Aug. 7, and that outlook
anticipates a very active season in the Atlantic basin.
It calls for 14-18 named hurricanes, versus a long-term average of eight. In
addition, it projects that three to six of them will be major hurricanes
(sustained winds of 111 m.p.h. or higher), versus a long-term average of
two.
CPC's lead hurricane forecaster Dr. Gerry Bell, noting the onset of a 20-40
year cycle of increased hurricane activity that began in 1995, says
additional factors that favor an active season in the Atlantic basin this
year include, "...reduced wind shear, weaker trade winds, an active West
African monsoon system ... and warmer-than-average water in the Atlantic
Ocean."

Thank you for checking in with Tom Skilling's Before the Forecast for Friday, August 15, 2008.

For the complete weather information, tune in to WGN News at 9pm for Tom Skilling's Full and 7-day forecasts.

Tune in tomorrow for another edition of Before the Forecast, and as always continue
to watch WGN for more coverage: Morning, Noon & Nine.

Amy Kostro tells us she was driving in Northwest Indiana on Route 31 in the Cedar
Lake/Lowell area this past Tuesday (Aug. 12) when she spotted this funnel. Amy's
vantage is such a good one we had to share her photos with you. Check them out--and
MANY THANKS Amy for sending them to us!
--Tom Skilling, Chief Meteorologist, WGN-TV/Chicago Tribune

Photos courtesy of Amy Kostro

Weather conditions challenged Chicago's Air & Water Show a year ago, but promise
nothing but clear sailing for the popular event that expands to three days this year.
More than an inch of rain fell on the show's second day in 2007 -- a remnant of
Tropical Storm Erin that had come ashore earlier in the week on the Texas Gulf Coast.
But sprawling high pressure will hold rain at bay this year. Friday's northeast winds will
be replaced by lighter onshore (easterly) breezes Saturday and a light west-to-
southwest flow Sunday. Temperatures warm by day to the 80s in an August running
5.3-degrees cooler than a year ago.

Several isolated but active thunderstorms swiped the Chicago area Thursday. Hardest
hit were northwest Indiana and Chicago's southwest suburbs. Schererville, Ind.,
topped area rainfall totals with .39 inch.

There's growing concern a westbound tropical system may be headed for hurricane
status in the days ahead. The system, in its infancy and churning west just north of
Haiti and the Dominican Republic on Friday, moves over energy-rich 86-degree waters
known to fuel storm intensification.

WEST BROILS WHILE PATTERN SHIFT PROMISES WARMER, MUGGIER WEATHER
HERE IN AUGUST'S FINAL WEEKS

--Tom Skilling, Chief Meteorologist, WGN-TV/Chicago Tribune

Dear Tom,
During recent severe storms, my mother-in-law said that she felt safe because it was
raining, which to her meant there can't be a tornado. Is there any truth to this?
Emlyn Hockin, Chicago

Dear Emlyn,
Absolutely no truth at all, but it's a common misconception. Jan Schaller, who
experienced the 1967 Oak Lawn tornado but remembers no rain during that event,
and Marcia Gross of Crown Point, Ind., whose high school science teacher said the
chance of a tornado is zero if it's raining, posed similar questions.

Most assuredly, rain can accompany a tornado.

Tornadoes exist is an environment of spiraling and strongly rising air, usually in the
southwest quadrant of the parent thunderstorm and a mile or two from the storm's
rain area. But winds swirling out of that rain area often carry rain entirely around the
tornado, thereby giving rise to a "rain-wrapped tornado."

Our thanks to Gary Wojton for sharing these shots of ominous skies above Fountain
Hills, Arizona. Moonsoon-fueled thunderstorms are shown sweeping the area.
Thanks Gary!!

Tom Skilling

Photos courtesy of Gary Wojton, Fountain Hills, Arizona

Thank you for checking in with Tom Skilling's Before the Forecast for Thursday, August 14, 2008.

Unfortunately, Tom Skilling and the WGN Weather Center are unable to bring you the Before the Forecast video tonight. But don't worry, we will have a brand new video on the blog tomorrow evening.

For the complete weather information, tune in to WGN News at 9pm for Tom Skilling's Full and 7-day forecasts tonight.

Tune in tomorrow for another edition of Before the Forecast, and as always continue
to watch WGN for more coverage: Morning, Noon & Nine.

Unlike the storm outbreaks of recent weeks, Wednesday's thunderstorms were
selective. The heaviest of them emanated from billowy cumulus clouds that towered as
high as 42,000 feet above the Chicago area and doused a few spots with gusty
downpours. Northwest suburban Mt. Prospect recorded .90-inch in just 30 minutes and
neighboring Arlington Heights was drenched by .70 inch. In typical summer fashion,
rainfall was uneven and affected just 30 percent of the Chicago area.

Northeast winds off Lake Michigan should act to stabilize the atmosphere in Chicago
on Thursday once some early morning showers depart. But daytime heating is likely to
produce a few thunderstorms at the periphery of the inland-moving lake air -- in the
far west and southern suburbs.

A 4TH AUGUST DAY IN THE 70S FOR FIRST TIME IN 4 YEARS

Wednesday's 79-degree high marked the fourth day of 70s in Chicago. That has not
happened in August's first two weeks over the past four years.

TROPICAL FORECASTERS KEEPING CLOSE EYE ON DISTURBANCE HEADED FOR BAHAMAS
--Tom Skilling, Chief Meteorologist, WGN-TV/Chicago Tribune

Dear Tom,
Your recently stated that our highest temperature so far this year has only been 91
degrees. Has Chicago ever had a year without a 90?
Rich Pokorski Morton Grove, Bob Ebersold Berwyn

Dear Rich and Bob,
Checking Chicago weather records dating back to 1871 there has been only one year
where the mercury failed to reach 90 degrees. In 1875 the highest official temperature
was 89 degrees logged on June 11. In those days the city's official thermometer was
located downtown, very close to Lake Michigan, so it is almost a certainty that inland
areas did reach the 90s. Forty years later in 1915, the city came close to another year
without a 90. But during a late-season hot spell, the mercury spiked to 90 degrees on
Sept. 14. Since the city's official thermometer was moved inland in 1942, the fewest
90s in a year have been two in 1979, three in 2004 and four each in 1967 and 2000.

Dear Tom,
Your recently stated that our highest temperature so far this year has only been 91
degrees. Has Chicago ever had a year without a 90?

Rich Pokorski Morton Grove, Bob Ebersold Berwyn

Dear Rich and Bob,
Checking Chicago weather records dating back to 1871 there has been only one year
where the mercury failed to reach 90 degrees. In 1875 the highest official temperature
was 89 degrees logged on June 11. In those days the city's official thermometer was
located downtown, very close to Lake Michigan, so it is almost a certainty that inland
areas did reach the 90s. Forty years later in 1915, the city came close to another year
without a 90. But during a late-season hot spell, the mercury spiked to 90 degrees on
Sept. 14. Since the city's official thermometer was moved inland in 1942, the fewest
90s in a year have been two in 1979, three in 2004 and four each in 1967 and 2000.

Thomas Nava of Chicago’s northwest side photographed this rainbow Wednesday evening
around 7 p.m. Thanks for sending this to us, Thomas!

-Tom Skilling

Photo courtesy of Thomas Nava, Chicago’s northwest side

Thank you for checking in with Tom Skilling's Before the Forecast for Wednesday, August 13, 2008.

Today was the 4th day in a row of low temperatures in Chicago. This is the 1st time in 2 years that the beginning of August has been this cool. This may be due to the brewing thunderstorms that are developing right now in the West. Expect active downpour in some areas, and scattered showers in others for tonight.

For the complete weather information, tune in to WGN News at 9pm for Tom Skilling's Full and 7-day forecasts.

Tune in tomorrow for another edition of Before the Forecast, and as always continue
to watch WGN for more coverage: Morning, Noon & Nine.

Few who witnessed the eye-catching "shelf cloud" which swept across
the Chicago area from the northwest back on Thursday evening, July 10
will ever forget it. The Chicago Tribune's John Smierciak was there and
produced these photos. Here, crew members are shown hurrying to get cars
and equipment under cover in the garage as a fast moving storm roared
in from the northwest. John recounts how the storm was greeted:

"The practice for the weekends races was winding down when someone
walked in to the media room the the Chicagoland Speed in Joliet, Il.,
and said calmly, "Looks like it might rain....". Always on the hunt for
weather photos for Tom's blog I went out to take a look. It was
unbelievable!! I turned to the crew member next to me who was also
frozen with his mouth open and asked, "Does this place have a
basement????" The front was rolling in so fast that you could watch the
clouds moving towards you. The track ordered all of the spectators to
bail out of the stands and all of the crews were hurrying to push their
cars into the garages. I climbed up on top of one of the team haulers to
make some shots looking down on the garages and the storm rolled in
closer to the track. The rain could be seen falling in the distance like
a waterfall I thought it was time to get off the hauler (lightning?) and
ran inside a garage. I fully expected high winds to wreck the track and
everything in it. Luckily, that didn't happen and the next day
everything went on as usual. I have to say that it was one interesting
afternoon......"

Interesting indeed! MANY THANKS, John, for the flashback to one of
this summer's most extraordinary storms! These images visually
transport us back to Thursday evening, July 10.

Tom Skilling

Photos courtesy of the Chicago Tribune's John Smierciak

Tuesday evening’s brief funnel cloud occurred without the threatening weather which so
often accompanies funnel cloud reports. Brian Hughes snapped the funnel on a camera
phone and was good enough to share it with us. Thanks Brian!

-Tom Skilling

Photo courtesy of Brian Hughes, Cedar Lake, Indiana

Elizabeth Raczek e-mailed us these photos of the funnel cloud which appeared for
about 10 minutes over Cedar Lake, Indiana. Elizabeth tells us:

“My daughter Amanda,was outside this evening cutting grass when she came in
the house to tell me she saw a Funnel cloud right outside in front of our home. We live
in Cedar Lake Indiana and she took these two pictures of the funnel and we both wanted
to share these with you. This is my very first time and hers seeing such a
funnel.”

The photos are terrific, Elizabeth. Our thanks to you and your daughter for sending
them along!

Tom Skilling

Photos courtesy of Elizabeth Raczek, Cedar Lake, Indiana

Congratulations to Tom Skilling for 30 wonderful years of reporting, researching, and sharing the weather with us here at WGN and across the Midwest!

August is the wettest and often the muggiest month of the year. Yet, summer heat
continues in short supply, continuing a trend that has dominated much of the 21st
Century’s opening decade. There have been only 162 days 90 degrees or warmer at
Midway Airport over the period from 2000 to 2008. That’s by far the fewest 90-degree
temperatures in the opening nine years of any decade on record here since 1930.

This summer’s highest reading to date has been just 91 degrees. That’s unusual. Since
1928, only one year—2000—has failed to record a higher warm-season temperature by
Aug. 13.

FUNNEL HOVERS OVER NW INDIANA LATE TUESDAY; HURRICANE FORECASTERS MONITORING ATLANTIC SYSTEM

A pocket of cool air aloft and the additional “lift” provided as air accelerates into a
pocket of strong jet-stream winds aloft produced a funnel cloud over northwest
Indiana on Tuesday evening. The funnel, which hovered over Cedar Lake and Lowell for
nearly 10 minutes, never touched the ground and dissipated without incident.

A disturbance in the Atlantic east of the Lesser Antilles threatens to strengthen and
become the next tropical depression. It is being watched by hurricane forecasters.

Dear Tom,
When it comes to humidity who has it worse- the Chicago area or Florida?
-Jim Carter

Dear Jim,
Humidity comparisons in terms of human comfort are best made with dew point, a
direct measure of atmospheric-moisture content. Most people begin to feel
uncomfortable when the dew point reaches the middle 60s. When it crosses the
threshold of 70, almost everyone is miserable. During a typical warm season, the
Chicago area will experience 70 degrees or higher on about 30 days. It would be
unusual for Florida dew points to not to reach the 70-degree level on any day during a
typical warm season. In fact, dew points in Florida and throughout the southeast
frequently approach 80 degrees in summer, something that has officially happened
only six times in the Chicago area since 1871.

Amanda Pickett shares THIS shot of Tuesday evening's northwest Indiana funnel cloud.
This photo was taken by Amanda's husband in Cedar Lake, Indiana.

Photo courtesy of Amanda Pickett, Cedar Lake, Indiana

We want to thank Dale Holsti, a paramedic at the Lowell Indiana
Volunteer Fire Department, for sending us these terrific photos he took
of funnel clouds which were spotted just west of Commercial Avenue and
Burr Street in Lowell around 6:50 P.M. Tuesday evening. Dale reports the
funnel was visible aloft for nearly 10 minutes. It never touched down.
The funnel was the result of marginally cool air aloft and some upward
vertical motion produced beneath the rear quadrant of a jet stream wind
speed maximum which extended from Michigan and Wisconsin off the
Atlantic Coast of North Carolina. Amy Seeley of the National Weather
Service reports the circulation was confirmed by a circulation observed
on terminal Doppler radar scans of the area. MANY THANKS to Dale Holsti
and his colleagues at the Lowell Volunteer Fire Department for the
photos and for the good work they do there! It was great having a chance
to talk with Dale and his colleagues Tuesday evening!

Tom Skilling

Photos courtesy of Dale Holsti

Thank you for checking in with Tom Skilling's Before the Forecast for Tuesday, August 12, 2008. Tom Skilling and the WGN Weather Center are proud to provide the Beijing Olympic Games with a daily weather forecast.

In today's video, viewers get to meet the new CLTV meteorologist, Duffy Atkins, originally from Chicago. In weather, the WGN Weather Center team are tracking a possible hurricane development, rain headed in our direction, and your storm update for the weekend.

For the complete weather information, tune in to WGN News at 9pm for Tom Skilling's Full and 7-day forecasts.

Tune in tomorrow for another edition of Before the Forecast, and as always continue
to watch WGN for more coverage: Morning, Noon & Nine.

Randy Stine, who lives in the Bucktown neighborhood, was standing in his apartment videotaping last week’s lightning just a foot from his metal balcony as last Monday’s powerhouse storm complex roared into the area...

Chicago's recent round of beautiful weather with unlimited visibilities and cool
temperatures -- among them the coolest highs in five weeks -- have seen overnight
lows as chilly as 49 degrees in far west suburban Rochelle and 51 degrees at nearby
DeKalb. Normal lows this time of the year are in the low 60s. As cool as those Chicago
area readings have been, minimum temperature in recent days across the North Woods
of Wisconsin have dipped to truly autumn-like levels, including 40 degrees at Ashland,
41 degrees at Merrill and 43 degrees at Superior and Antigo. The cool readings are the
product of northwest steering winds that have guided Canadian air across the Midwest.

Thunderstorms on the west side of this cool air pummeled sections of Nebraska on
Monday. They towered to 51,000 feet and unleashed nearly 5 inches of rain on Butte --
on the Nebraska/South Dakota border.

WEATHER BEING MONITORED IN THE ATLANTIC COULD BE TROPICAL TROUBLE

Two areas of disturbed weather are being monitored by tropical weather forecasters at
the National Hurricane Center. Either or both may develop into tropical depressions in
the next day or two.

--Tom Skilling, Chief Meteorologist, WGN-TV/Chicago Tribune

Dear Tom,
Who coined the term, "global warming"?

Billy Evans, Maywood, Ill.

Dear Billy,
Two weeks ago, we contacted the man who put "global warming" in the world's
consciousness and his humble response was, "I guess I did, but it was inadvertent."
Those are the words of Dr. Wallace Broecker, the world's premier authority on abrupt
global climate change and a long-time researcher at Columbia University's
Lamont-Doherty Earth Observatory.

And you will be surprised to learn that "Wally," as he chooses to be called, is a native of
west suburban Oak Park.

In 1975, worldwide temperatures had been falling for 20 years (Chicago's too) and the
concern was that the planet was heading into a new ice age. Broecker dismissed that
concern and, in the same year, published a paper titled, "Climate Change: Are We on the
Brink of a Pronounced Global Warming?" The phrase caught on.

Thank you for checking in with Tom Skilling's Before the Forecast for Monday, August 11, 2008.

Tom Skilling and the WGN Weather Center are proud to provide the Beijing Olympic Games with a daily weather forecast. Weather in the Chicago-land area is very different from China, as August is the month with the highest levels of precipitation for this area. Today, we saw clear skies and cool winds across the region.

For the complete weather information, tune in to WGN News at 9pm for Tom Skilling's Full and 7-day forecasts.

Tune in tomorrow for another edition of Before the Forecast, and as always continue
to watch WGN for more coverage: Morning, Noon & Nine.

Donna Braden lives two blocks from the Peggy Notebaert Museum and looked out her
fourth floor window last Tuesday morning to see this plastic pink flamingo lodged in a
tree above her parking lot. It had been blown there from the lawn exhibit in front of the
Notebart Museum which had featured a flock of pink plastic flamingos by last Monday’s
storm. Donna closes her e-mail to us asking, "Did you know pink plastic flamingos
can fly?" That’s news to me!! Thanks Donna for offering us a chuckle on a Monday! All
the best!

Tom Skilling

Photo courtesy of Donna Braden, Chicago

With a northwest flow aloft steering Canadian-source air into the western Great Lakes and predominantly easterly surface winds, temperatures this week look to average a little below normal. High pressure will center over Lake Michigan Monday and then edge into the eastern Great Lakes later Tuesday, where it will hold until late week. Meanwhile, low pressure in the Northern Plains will move into the upper Mississippi Valley. For Chicago, sitting on the edge of these two weather regimes, this eastward movement will mean much more cloudiness and a chance of rain as early as late Tuesday.
If computer models prove correct, a very unusual low pressure circulation aloft could drift slowly southeast in the northwesterly flow, enhancing development of a broad moisture-laden low pressure surface system that could mean a 48-hour-plus period of showers and thunderstorms for northern Illinois next weekend.
HEAVY RAINS OVER SOUTHEAST U.S.
Pushed to the Gulf Coast by the strong northwest flow aloft, a stationary front oriented west-east through the Southeast will trigger heavy rains, well in excess of 2 inches, over most of the southeastern Gulf Coast states the first half of the week.
--By Paul Dailey, WGN Weather Center Meteorologist

Dear Tom,
Automobiles are always mentioned as one of the contributors to global
warming because they produce carbon dioxide. How much does a car produce?
Richard Waller, Chicago
Dear Richard,
You probably don't realize how much carbon dioxide (CO2) you're putting into
the atmosphere when you operate your automobile. If your car gets 26 miles
per gallon (and that is much better than the national average of 21 mpg),
one pound of CO2 comes out of your tailpipe every mile.
CO2 exists naturally as a trace component of the atmosphere (amounting to
385 parts per million (ppm) of dry air). Despite its low concentration, it
is a powerful "greenhouse gas" in that it contributes to the atmosphere's
ability to retain heat (the so-called greenhouse effect).
Right now, CO2 concentration is increasing at a rate of just under 2 ppm per
year, and automobiles are a big contributor.

With the upper-level jet stream flow poised to hold out of the northwest,
Canadian-origin high pressure air masses are expected to influence Chicago's weather
into next weekend. There should be only minor day to day variations in temperatures,
averaging near or slightly below normal for this point in August. Low pressure midweek
may give a 48-hour period of unstable weather featuring periods of showers and
thunderstorms starting later Tuesday extending into Thursday. Bathers along the south
end of lake Michigan are cautioned to watch for rip currents today and Monday as north
winds build waves over the open water.

YEAR'S LONGEST 80-DEGREE-PLUS STRING ENDS SOONER THAN NORMAL

Climate records at Midway airport reveal that in a typical year at least 23 consecutive
days of 80-degree-plus highs are recorded. This past Friday's high of 79 degrees ended
a 16-day string of 80s--likely to be 2008's longest.

METEOR SHOWER SIGHTING LIKELY

According to Dan Joyce of Triton college's Cernan Earth and Space Center, 2008 Perseid
meteor shower activity will peak later Monday and early Tuesday.

Dear Tom,

Are there specific conditions which predispose to visualization of a double or
supernumerary rainbow?

-Jon Sebastian, Bensenville

Dear Jon,
Area residents were treated to a display of double rainbows (primary and secondary) on
three occasions last spring. A primary rainbow forms when sunlight passes through
raindrops and, after refraction and a single reflection within a raindrop,returns to our eyes
separated into the colors of the spectrum. A wider, fainter secondary rainbow forms
outside the primary when some of the light is reflected twice within the raindrops before
emerging. Supernumerary rainbows sometimes form inside the primary when the
raindrops are all very uniform in size. They result from interference of light, which
undergoes a single internal reflection but travels along different paths inside a raindrop.

Thunderstorms may flare later Saturday, developing in several clusters along a
southbound cold front that approaches this afternoon and passes with a wind shift to
the north in the evening.
Though hardly the muggy air mass that gripped the area earlier this week, the
atmosphere here will hold nearly 1.2 inches of evaporated water later Saturday. Surface
winds converging along the cold front while winds aloft diverge (move apart) signal that
thunderstorm-generating large-scale "lift" is being generated.
At the same time, faster-than-normal vertical temperature declines are to set up,
encouraging air to rise with gusto. Stronger than usual upper-level northwest steering
winds are likely to push along any thunderstorms that might erupt, increasing the
threat they'll become strong wind producers. The remnants of overnight thunderstorms
to Chicago's northwest may manage a sprinkle from mid-level clouds Saturday
morning, but the hope is most rainfall will await the front's arrival late Saturday.

CHICAGO'S 16-DAY STRING OF 80s AND 90s ENDS; COOLEST HIGH IN 2.5 WEEKS
Friday's 79-degree high may have ended this warm season's longest
80-degree-plus spell.
--Tom Skilling, Chief Meteorologist, WGN-TV/Chicago Tribune

Dear Tom,
My husband noticed clouds moving from north to south and from west to east
at the same time. Is this because winds were changing with altitude?
Carol Richart
Dear Carol,
You are absolutely correct. Clouds range from stratus and fog that hug the
ground to feathery ice-crystalline cirrus found above 30,000 feet to the
anvil tops of thunderstorms that can reach more than 60,000 feet into the
atmosphere. Cloud movement is, of course, determined by wind -- and winds
can change dramatically with height depending upon the meteorological
scenario. A common occurrence in Chicago would be low-level winds below
8,000 feet blowing from east to west while jet stream-level winds above
25,000 feet are traveling from west to east. In meteorology, when the wind
direction changes clockwise with height winds are said to be veering, and
when shifting counter-clockwise they are backing.

Thank you for checking in with Tom Skilling's Before the Forecast for Friday, August 8, 2008.

Today we had a beautiful high of 79 degrees, the coolest high in over two weeks. We saw light puffy clouds and blue skies all day. Tom has detected an area of rain developing up in the Northwest region, but he predicts that by the time it gets to Chicago, it be a mere sprinkle in the morning.

Enjoy your weekend, and as always, thank you for checking in with Before the Forecast.

Tune in tomorrow for another edition of Before the Forecast, and as always continue
to watch WGN for more coverage: Morning, Noon & Nine.

As Chicagoans reveled in Thursday's picture-perfect weather, Michigan beachgoers not
more than 72 miles away were dazzled by a series of waterspouts spawned just before
noon by a southbound cluster of thunderstorms. Cool air above mid-70-degree waters
encouraged warmer, more buoyant air to rise and set the stage for the 20,000-foot-tall
thunderstorms from which as many as three waterspouts emerged just west of South
Haven, Mich., sending spray hundreds of feet into the air. The waterspouts never came
ashore, where they would have turned into tornadoes.

Chicago has lost 1 hour and 5 minutes of sunshine since June 20 -- the year's longest
day and astronomical start of summer. Seasonal loss of sunshine occurs fastest at
higher latitudes. Barrow, Alaska, will see 3.7 fewer hours of sun Friday.

ACTIVE SEASON TO DATE JUST A WARM-UP; HURRICANE FORECASTERS BOOST 2008 FORECASTS

NOAA's Climate Prediction Center, citing the active nature of the 2008 hurricane season
to date, has boosted odds of an above-normal season from 65 to 85 percent and now
predicts 14 to 18 named storms, including seven to 10 hurricanes -- three to six of
them potentially major (Category 3 with 111 m.p.h. winds or higher).

--Tom Skilling, Chief Meteorologist, WGN-TV/Chicago Tribune

Dear Tom,
What is Chicago's record for consecutive days with 90-degree or higher temperatures?
And with so few 90-degree days this year, what is the longest stretch between 90
degree days?
Nick Recchia, River Grove, Ill.

Dear Nick,

When it comes to hot days, think of Chicago as a city with two climates: a cool regime
within about a mile of Lake Michigan that gradually morphs into a hot "inland" climate
beyond five miles from the shore.

On average, the lake zone experiences far fewer 90-degree days per year (eight) than
inland (24 at Midway Airport). Consecutive 90-degree days at the lakefront rarely
extend beyond five days, but Midway has logged a string of 12 days at or above 90
degrees (July 6-17, 1936).

Downtown Chicago went without a single 90-degree day from Aug. 22, 1874, to July 5,
1876 -- 684 days. At Midway, the longest such stretch is 340 days (July 2, 1967 to June
5, 1968).

Thank you for checking in with Tom Skilling's Before the Forecast for Thursday, August 7, 2008.

A few days after massive winds and lightning, Chicago enjoyed a nice 72 degree day along the shoreline today. Beachgoers were excited to see some water spouts - small tornadoes over the waters of Lake Michigan earlier in the day.

The air is cool for this time of year in August, but Tom suggests we all enjoy it!

Tune in tomorrow for another edition of Before the Forecast, and as always continue
to watch WGN for more coverage: Morning, Noon & Nine.

Duane Fimreite e-mails to say his wife Kathryn took this photo of the waterspout which
formed over Lake Michigan to the west South Haven early Thursday afternoon. Thanks
Duane and Kathryn for this great shot!

Tom Skilling

Photo courtesy of Duan and Kathryn Fimreite

Mariel Knot has forwarded us these truly spectacular photos she and her sister Anneke
and brother David took of a waterspout off South Haven, Michigan early Thursday
afternoon. Mariel tells us that her family is from Flossmoor and that they have been
vacationing in South Haven. I'm sure any kind of encounter with a waterspout was the
last thing on Mariel and her family's mind as the looked out over the lake and were
greeted by this sight! These photos were taken at 11:15 pm Chicago time.

The waterspout picture here was spawned by a cluster of showers and thunderstorms
which traveled south over the east end of Lake Michigan during the night and during
morning hours. The destabilizing effect of cool air aloft led to the thunderstorm
development. The Grand Rapids National Weather Service Office issued a special marine
warning advising mariners of the danger posed by the waterspout and warning of the
potential of others. Many thanks Mariel, her brother David and sister Anneke for
sharing these photos with us! They are terrific!

Tom Skilling

Photos courtesy of Mariel, Anneke and David Knot

Northwest winds guide a series of comfortable Canadian air masses into the Midwest
over the next several weeks, all but eliminating Chicago's exposure to prolonged heat.
Surges of humid air will raise the possibility of thundery weather from time to time --
the next due here Monday into Tuesday. While predominantly dry weather occurs the
next few days, bright sun and a hint of instability in the warmer hours, minor
jet-stream disturbances and converging winds along an inland-moving lake breeze
Thursday and Friday afternoons may ignite spotty showers or t-storms. Known as
diurnal thunderstorms because they bubble into existence as temperatures rise and
low-level air becomes buoyant, they fade quickly once the sun sets.

Gusty thunderstorms swept across Lake Michigan into the area between Holland and
Grand Rapids last night behind an eye-catching shelf cloud. Similar t-storms in
southwest Wisconsin late Wednesday produced 50 m.p.h. wind gusts and 1-inch hail
near Dodgeville.

DENVER'S RECORD-BREAKING 24-DAY 90+ DEGREE STREAK ENDS -- FINALLY!

Denver -- after a record-breaking 24 consecutive days above 90 -- reported a high of
just 88 degrees Wednesday.

--Tom Skilling, Chief Meteorologist, WGN-TV/Chicago Tribune

Our friend John Gehr tells us thunderstorms rolled into Michigan’s lower peninsula
Wednesday evening led by an impressive shelf cloud. You can check out more of John’s
shots here. One of a rain-shaft looks deceptively like a tornado (thankfully it’s not!).
Thanks John for the great photos and all our best to you and your neighbors who check
in with us from Lower Michigan!!

-Tom Skilling

Photos courtesy of John Gehr

Dear Tom,
Does sunset occur when the sun first touches the horizon or when it dips below it?

Dan Stecich Orland Park

Dear Dan,
Sunset and sunrise are defined as the moment that the upper edge of the sun's disc
touches the horizon. At the exact time of sunrise or sunset the sun's disc is actually
below the horizon, but because the Earth's atmosphere bends or refracts light, we are
able to see the sun earlier in the morning and later in the evening than if we were
viewing it in a vacuum. Since the higher we are, the farther we can see, a person atop a
high-rise building or on a mountain will actually experience an earlier sunrise and a
later sunset than someone at ground level. Also the few extra minutes that we are able
to see the sun is the reason that the length of daylight on the equinoxes or at the
equator is slightly greater than 12 hours.

Thank you for checking in with Tom Skilling's Before the Forecast for Wednesday, August 6!

The weather patterns have changed dramatically today, and Tom is tracking the winds sweeping into Chicago from the Northwest and Canada. As a result, you can expect cooler temperatures for summer during the rest of this week.

Tune in tomorrow for another edition of Before the Forecast, and as always continue
to watch WGN for more coverage: Morning, Noon & Nine.

These shots sent to by National weather Service storm spotter Thomas Nava were taken in the Harwood Heights area.

Photos by Thomas Nava

Bob Korbus took this photo on Chicago's northwest side not far from the Kernnedy Expressway and Nagle Avenue. near the inteersection of Melvina and Balmoral.

Photo by Bob Korbus

It's official -- Monday evening's fast-moving squall line unleashed at least three
tornadoes as it blasted across the area with lightning displays few here will soon
forget. Twisters were behind the damage in Griffith, Ind., hit by an EF-2 (Enhanced
Fujita scale-2) intensity tornado (111-135 m.p.h.), Bloomingdale in Du Page County,
where an EF1 twister (65-85 m.p.h.) struck, and Bolingbrook in Will County, where an
EF1 tornado (86-110 m.p.h.) was reported. Until Monday's storms, August had hosted
only 23 of the 119 summer-season twisters recorded since 1950 across the 14
counties closest to Chicago from southeast Wisconsin into northwest Indiana.

The 2.43 inches of rain that accompanied Monday's storms at O'Hare pushed
meteorological summer rainfall (since June 1) nearly five inches above the 137-year
average here. The deluge makes this summer the wettest here since 1993.

THUNDEROUS 6-INCH-PLUS CLOUDBURST DRENCHES NORTHWEST INDIANA BEFORE SUNRISE TUESDAY

As the intense t-storms slowed across the southern portion of the metro area and
moved into northwest Indiana early Tuesday morning, rainfall totals increased
significantly, peaking in excess of 6 inches in and around the Valparaiso, Ind., area.

--Tom Skilling, Chief Meteorologist, WGN-TV/Chicago Tribune

Dear Tom,
I live on the northwest side of Chicago and we had half-inch hail in the storms Monday
evening. Has hail ever caused any deaths?

John Lewis, Chicago

Dear John,

Large hail is extremely costly, with annual damage totals approaching, and
sometimes exceeding, $1 billion but, in the United States at least, deaths
attributed to hail are exceedingly rare. Most recently, a Fort Worth
man succumbed to head injuries after being struck by a softball-sized (4.5
inches in diameter) hailstone in March, 2000. Hailstones that large weigh
several pounds and crash to earth at 90 miles per hour, making them
potential instruments of death.

An aspect of hail that is often overlooked is the significant threat that it
poses to birds. Large hail, especially when accompanied by high thunderstorm
winds, kills thousands of birds in this country every year.

Good news for tonight! The big storms from last night are mostly gone, so you should expect NO thunderstorms tonight in the Chicago metro area. Most of the scattered storms for tonight will be concentrated in downstate Illinois.

Today had a high of 86 degrees. You can expect colder weather coming later on tonight as we move into a cooler weather pattern.

Tune in tomorrow for another edition of Before the Forecast, and as always continue
to watch WGN for more coverage: Morning, Noon & Nine.

CLICK HERE to check out the pictures and radar image animation progression on Walker Ashley's BLOG

Photos courtesy of Shane Bradley, Chicago

Photos courtesy of Steve Bolich, Schaumburg IL 60195

Photos courtesy of Mike Frankowski, South Elgin

Photos courtesy of Tracey Surface, Chicago

There's little doubt that Monday evening's phenomenal and often violent storms were in
a league all their own--certainly the most powerful storms of the summer and quite
possibly among the strongest to sweep the metro area as far back as most of us who
keep track of such things can remember. You--our WGN viewers and our blog
visitors--have sent us a spectacular array of photos from every corner of the are and I
want to share these with all. We’re going to try and post as many as we can, knowing
we’ll not get to all of them. MANY THANKS for the time and effort in photographing
and then sending us the spectacular array of images you’ve each shared with us! Check
these out and enjoy……

Tom Skilling


Photos courtesy David Mayhew, Chicago

Thanks to Caludine Brumfield from Bolingbrook for this pictures of the ominous skies just before the heavy rains and wind hit last night.

Photo by Claudine Brumfield

This picture taken by Keefer near Hermitage and Pearson shows tree damage in the area.

Photo by Keefer

Steve Kahn WGN Weather Center

Thanks to Cynthia, Kat and Al Prawdzik for sharting these shots of tree damage taken on Humboldt Boulevard.

Tiffany from Orland Park was working at a boutique on Milwaukee Avenue around 8:30 when the storms hit. After the storm they nitoced thant an entire brick panel containing windows had been blown out of a building on the second floor. Luckily no one was hurt.

Steve Kahn WGN Weather Center Meteorologist

A violent squall line swept across the Chicago area Monday evening, packing
hurricane-strength winds as high as 94 m.p.h. recorded at the Harrison-Dever Crib just
off the downtown lakefront. Fueled by hot and humid air, the storms left a trail of
downed trees, some 1 to 2 feet in diameter and power lines from northwest Illinois all
the way to Lake Michigan.

Damage was severe in Mt. Morris, where a building was leveled, and a grain bin and a
phone tower were blown down.

Several homes were damaged in Bolingbrook and a tornado was reported on the ground
in Schiller Park. The lightning display was incredible at one point, reaching 10,000
strokes in just one hour. Branches littered streets in Chicago's Wrigleyville area and
standing water flooded streets in the wake of torrential downpours.

WILTING DOWNSTATE HEAT AND HUMIDITY SENDS HEAT INDEXES OVER 115-DEGREES
Downstate weather was suffocating Monday with heat indexes reaching dangerous
levels. Alton, just east of St. Louis posted a heat index of 124 degrees, while Rantoul
reached 114 and Springfield 112.

--Steve Kahn, WGN-TV/Chicago Tribune Meteorologist

Dear Mr. Skilling,
Could a hurricane be broken up by a big explosion in its eye?
Herbert Ferguson

Dear Herbert,

"Hurricane modification by any means, including brute force interference, is an exercise
in futility and impracticality." wrote Dr. Chris Landsea of the National Hurricane Center's Research Division.

The largest explosion that can be generated -- a hydrogen bomb - - is simply too
small to disrupt a hurricane, even in its formative stages.

Landsea concludes, "Perhaps the best solution is not to try to alter or destroy tropical
cyclones, but just learn to co-exist with them better."

Consider this: Hurricanes feed off the heat drawn from warm ocean water. In their
aftermath, the ocean surface is a cooler and less favorable environment for new tropical
storms. Without dissipation, the oceanic store of heat would build and build, ultimately
fueling even stronger hurricanes.

Mark Sreniawski shares these shots of the ominous cloud formations accompanying
Monday night’s storms as they moved into Plainfield around 7:30 p.m. Thanks Mark!

-Tom Skilling


Photo courtesy of Mark Sreniawski, Plainfield, Illinois

Stephanie Kosmicki shares this shot of Monday evening's lightning-described my many with whom we talked as one of the most dramatic cloud to ground lightning displays in recent memory. Thanks Stephanie

Photo by Stephanie Kosmicki

Mondays storm as seen from Oswego. Thanks to Tom Janito for this view of Monday's powerful thunderstorms as they swept through Oswego.

Photo byTom Janito

Lightning stroke arc eastward over Plano, Illinois late Monday evening.
Carl Armstrong reported that the "wind was so strong it threw my grill across the backyard!"

Photo by Carl Armstrong

There is a severe thunderstorm warning in effect for tonight until midnight. Violent thunderstorms may break in the Chicago area later tonight, so be sure to watch the WGN News at 9 for more weather updates.

Tune in tomorrow for another edition of Before the Forecast, and as always continue
to watch WGN for more coverage: Morning, Noon & Nine.

Check out this animation and several stills of Monday morning's
turbulent thunderstorm outflow as photographed by Dr. Walker Ashley of
NIU's Atmospheric Sciences Department:

CLICK TO SEE PHOTOS & ANIMATION (MONDAY AUG. 4)

-Tom Skilling
Photos and animation courtesy of Dr. Walker Ashley, Professor of
Meteorology, Northern Illinois University
--Tom Skilling, Chief Meteorologist, WGN-TV/Chicago Tribune

These skies sent a clear message as they rolled into Bedford Park around 8 am Monday
morning--a storm was on the way! Chuck Hagen provides this photo of the
approaching storms. Thanks Chuck!

Tom Skilling

Photos courtesy of Chuck Hagen, Oak Lawn, Illinoisag

Monday morning's storms moving in on Waukegan Airport
These ominous skies preceded Monday morning's storms are they bore down
on Waukegan Airport. Anson Mount has provided us this photo. The storms
produced 40+ mph wind gusts across harder hit northern suburbs according
to our Weather Bug sensors there and produce location 0.75" to 1"
northern Illinois totals and 1.28" of rain farther north in Racine,
Wisconsin. Thanks for another great photo Anson!

--Tom Skilling, Chief Meteorologist, WGN-TV/Chicago Tribune

Photo courtesy of Anson Mount

Dew points in the 70s will arrive in Chicago Monday as a saunalike air mass that has had
the Plains baking for days makes inroads into the Midwest. Highs will flirt with the
90-degree mark from the city northward as clouds and thunderstorms keep the mercury
in check, but readings should climb to the middle 90s in the far south suburbs. Heat
advisories are posted for areas south of Interstate 80 where readings in the middle and
upper 90s coupled with dew points in the 70s will produce heat indexes as high as 105
degrees.
The muggy conditions should be nothing more than a memory by Wednesday as a
refreshingly cooler and drier air mass moves in for an extended stay.

TROPICAL STORM EDOUARD DEVELOPS
Low pressure in the western Gulf of Mexico quickly intensified into Tropical Storm
Edouard Sunday afternoon with an expected Texas landfall early Tuesday, possibly as a
hurricane.

--By Steve Kahn, WGN Weather Center Meteorologist

Dear Tom,
I just heard a tape of the July 23, 1976, College All-Star Football game at
Soldier Field. The game was stopped by rain. What happened?
Tony Warren
Dear Tony,
The game started in very warm, muggy conditions with temperatures in the
upper 80s. There was a threat of severe weather, and it began to rain
heavily as the game began. Small hail and gusty winds accompanied the
thunderstorms. The rain ended, and the game continued on a sloppy field.
With the Pittsburgh Steelers leading the College All-Stars 24-0 late in the
third quarter the heavens opened up again as severe thunderstorms struck.
Winds gusted to 64 m.p.h. as the rain fell in torrents. The game was
stopped, but as the players left the field unruly fans ran out and knocked
down both goal posts. Even though the rain let up the game was cancelled. It
was the last College All-Star game ever played.

After a warm and increasingly humid weekend, Chicago is slated for a major- league
burst of heat and humidity Monday with readings expected to reach the middle 90s—
the hottest weather so far this summer. Before the heat moves in Monday afternoon,
the city may have to deal with several bouts of showers and thunderstorms that could
dump some heavy rainfall here mainly Sunday night and early Monday.

Once the heat arrives on gusty southwest winds, readings should quickly surge into
the middle 90s, and, combined with a dose of Gulf Coast-level humidity, heat
indexes could approach 100 to 105. So far this summer the city has not seen a
temperature higher than 91 degrees, something that has only happened twice in 80
years at Midway Airport: first in 1979 and again in 2000.

The heat should quickly retreat as cooler northeast winds set in by Wednesday and
dominate through the rest of the week.

DENVER SHATTERS MORE HEAT RECORDS

A 130-year-old high-temperature record fell in Denver Saturday, when the mercury
hit 103 degrees, besting the old record of 100 recorded in 1878. Denver has logged
an unprecedented 21 consecutive 90-degree-plus days, with more expected. The
city’s previous string of 90s was 18 in 1878 and 1901.

Dear Tom,
What would happen to our weather if we didn't have a moon?
--Robert Lamm
Dear Robert,
In the short term, nothing at all. The moon's contribution to an atmospheric tide (and
ocean tides, as well) would cease, but without weather consequences. Through the
millenniums, though, the moon has exerted a huge stabilizing influence on the Earth's
climate. The Earth's axial spin (a spin that produces our 24-hour day) tilts at an angle of
about 66.5 degrees from the plane of our orbit around the sun. That tilt, stabilized by the
moon, causes the yearly cycle of seasons. In the moon's absence, the Earth would behave
almost like an unbalanced spinning top, with its axial tilt rolling erratically between 0 and
90 degrees over thousands of years. The result:climatic chaos with much larger
temperature swings between the warm and cold seasons.

A succession of downpour- and small- hail-producing thunderstorms erupted along an
inland-moving lake breeze Friday in southern Cook County, then swept into and across
northern Indiana. Winds converge at ground level along such lake- breeze fronts,
allowing air no recourse but to ascend in humid columns of air. The towering
thunderheads produced through this process -- referred to as cumulonimbus clouds
by meteorologists -- are often spectacular in appearance, taking on the form of
cottony masses within which lightning can be seen flashing. One of the storms
produced 0.60 inches of rain in just 10 minutes in Ft. Wayne, Ind.
Saturday will be rain-free -- cooled by north-to-northeast winds that import
noticeably drier air from Canada. Heat will begin to make inroads here Sunday, but will
likely be tempered by storm outflows.

BLAZING HEAT OVER 13 STATES REACHES
CHICAGO MONDAY INTO TUESDAY
High-temperature records fell in six states Friday, led by 104-degree highs in both
Denver and Miles City, Mont.
Excessive-heat advisories are posted for Saturday across 13 states from Montana to
Texas as an expanding western heat dome spreads into Chicago, bringing this
summer's hottest weather by Monday.
--Tom Skilling, Chief Meteorologist, WGN-TV/Chicago Tribune

Dear Tom,
Your weather forecasts have become noticeably more accurate over the years.
What technological advances have made that possible? Or are you just lucky?
John Carlson, Arlington Heights
Dear John,
It can't be denied: On rare occasions, luck is a factor in an accurate
weather forecast. However, a reasonably consistent record of accurate
forecasting depends on much more: At long last, weather forecasting has
truly become a science.
More now than ever before, meteorologists have a better understanding of the
atmosphere's physical processes and of the complex relationships between
air, land and oceans. Add to that astounding advances in communication,
worldwide weather observations and satellite and radar technology.
It's more information than a forecaster can handle, but today's phenomenally
speedy computers can process all the data in new, timely and imaginative
ways.

Randy Becker captured these great shots of the Indiana thunderstorms from Sublette in north central Illinois.

Photo by Randy Becker

This great shot of this evening's thunderstorms that passed through northwest Indiana was sent to us by Gerry from Valparaiso. The storms passed to the south of Valparaiso leaving them high and dry, while areas farther south got blasted.

Photo by Gerry

Our thanks go out to Amanda Pickett of Winfield, Indiana for sharing this picture of a line of thunderstorms passing to the south of Winfield in northwest Indiana, just east of Crown Point. Amanda notes that her garden got quite a watering this afternoon from these storms.

Photo by Amanda Pickett

Thank you for checking in with Tom Skilling's ‘Before the Forecast’ for Friday, August 1, 2008.

Meet the meteorologists! Tom introduces the WGN Weather Center team to all you viewers ... well, he gives you their names anyway.

Today, expect small localized thunderstorms in 10-20% of the Chicago area. Tom is also watching the lake breeze coming inland with a cooling effect that's just in time for the hot summer weekend.

Tune in tomorrow for another edition of Before the Forecast, and as always continue
to watch WGN for more coverage: Morning, Noon & Nine.

Mark and Karen Vogan have been traveling across the Irish countryside and have e-mailed
us these wonderful photos of Northern Ireland, including shots of the rugged cliffs which
line northern Ireland's Atlantic coastline in the north. Our thanks to Mark and Karen for
sharing these views of the fabled, often wind-tossed Irish coastline with us! It appears
the trip was a great success. You've shared it with us through your magnificent photos!

Photos courtesy of Mark and Karen Vogan

--Tom Skilling, Chief Meteorologist, WGN-TV/Chicago Tribune

Winds gusted above 30 m.p.h. at some locations in and near Friday morning's cluster of
thunderstorms as indicated by our WeatherBug network. The storms swept across the
Chicago area and organized into a long but very narrow band which during the period
from 4 to 7:30 a.m. extended from DeKalb County to just west of Fort Wayne, Ind.

Anson Mount photographed the underside of one of this morning's thunderstorm anvil
tops from his vantage point in northwest suburban Algonquin. Thanks Anson!

Photo courtesy of Anson Mount, Algonquin, Illinois

--Tom Skilling, Chief Meteorologist, WGN-TV/Chicago Tribune