EXPLAINER: September 2008 Archives

It's getting to be the time of year when lake-effect precipitation appears on the weather
scene. Mention lake-effect precipitation and Chicagoans invariably think of snow.
However, if temperatures are sufficiently cold to generate precipitation but not quite
cold enough for snow, the atmosphere gives us lake-effect rain. That's the situation
today. Residents of northern Indiana can expect rain showers today and tonight, the
result of chilly air surging down the full length of Lake Michigan's relatively warm
waters. Steering winds, blowing north to south, may carry a few showers onto the
near-shore areas of Chicago.

CHICAGO'S OCTOBER SNOW

A trace of snow has been observed in Chicago as early as Sept. 25 (in 1942) but the
city's snow season doesn't really get under way until November. But don't count out
October: It's had its snowy moments. Eighty years (1928-2007) of Midway snowfall
data reveals that 38 Octobers (about one out of two) have delivered at least a few
snowflakes. Measurable snow (an accumulation of one-tenth inch or more) occurred in
11 Octobers (one October out of seven) and an inch or more has come down in four
Octobers (one out of 20).

--By Richard Koeneman, WGN Weather Center Meteorologist

A cooling trend that began on Sunday continues today, gathers strength Tuesday and
arrives with vigor on Wednesday and Thursday. Saturday’s 81-degree reading is a warm
memory, and before the cooldown runs its course, Chicago’s temperatures will have
declined to an expected early-morning minimum of 41 degrees on Thursday. That’s a
40-degree plunge over a five-day period.

Air of Canadian origin surges into Chicago Tuesday on the wings of 25 m.p.h. winds from
the northwest, and jackets will be the order of the day. Afternoon temperatures won’t
make it out of the 50s on Wednesday and Thursday, though winds will subside.

HIGHS IN 50s THIS TIME OF YEAR: RARE

Historically, Chicago’s highs have failed to reach 60 degrees on only 14 percent of the
days on record during Sept. 29-Oct. 3.

A cooling trend that began on Sunday continues today, gathers strength Tuesday and
arrives with vigor on Wednesday and Thursday. Saturday's 81-degree reading is a warm
memory, and before the cooldown runs its course, Chicago's temperatures will have
declined to an expected early-morning minimum of 41 degrees on Thursday. That's a
40-degree plunge over a five-day period.
Air of Canadian origin surges into Chicago Tuesday on the wings of 25 m.p.h. winds from
the northwest, and jackets will be the order of the day. Afternoon temperatures won't
make it out of the 50s on Wednesday and Thursday, though winds will subside.

HIGHS IN 50s THIS TIME OF YEAR: RARE
Historically, Chicago's highs have failed to reach 60 degrees on only 14 percent of the
days on record during Sept. 29-Oct. 3.
--By Richard Koeneman, WGN Weather Center Meteorologist

Upper-level "steering winds" (the winds, blowing 20,000 to 30,000 feet aloft that govern
the movement of weather systems at the surface) will shift from westerly to northerly
early this week.
That means chilly air centered over western Canada will be directed into the Great Lakes
region.
Only the southern (and mildest) portion of that Canadian air mass will affect Chicago
today and Monday, but it will be enough to lower readings 10 degrees from Saturday's
balmy 81-degree high. An additional 10-degree drop occurs Tuesday.

WARM-UP EXPECTED IN SEVEN DAYS
By next weekend, the jet stream is expected to shift to a southwesterly flow over the
central portion of the United States, bringing significant warming to Chicago and the
upper Midwest.
--By Richard Koeneman, WGN Weather Center Meteorologist

Summer-weather enthusiasts will enjoy a final day of sunny, warm weather today. A
look at Chicago's climatic history tells us that a few 80-degree days at this time of year
are not at all unusual. In fact, it happens in 6 out of 10 years. The end lies just ahead,
however. The first surge of cooler air arrives Sunday, and a second and more powerful
surge -- of Canadian origin -- pushes into the area on Tuesday. Blustery, chilly
conditions will dominate conditions on Wednesday and Thursday.

WINDY, RAINY WEATHER HITS ALONG
THE ATLANTIC COAST THIS WEEKEND
Tropical Storm Kyle, predicted by the National Hurricane Center to intensify to
hurricane status, sweeps northward just off the Atlantic Coast. It's due to make landfall
late Sunday on the coast of Maine and then crash northward into Canada's Maritime
Provinces. Heavy and flooding rains, high winds and major shoreline erosion are a given
in such situations.
Hurricanes, while rare visitors to New England, are not unknown -- and that applies to
Canada's Maritime Provinces as well. The National Hurricane Center advises that a
slight eastward shift in the forecast trajectory of the storm would significantly lessen
its impact on New England.
--By Richard Koeneman, WGN Weather Center Meteorologist

Wide temperature swings expected in the next 10 to 16 days are a reminder that
Chicago's weather is marching to an autumnal drum. Summery temperatures Friday and
Saturday will yield to cooler air Sunday and then yield further to showery, windy and
much cooler weather Monday and Tuesday. Afternoon readings in the lower 80s Friday
collapse to nighttime temperatures in the lower 40s by the middle of next week. That's
a 40-degree plunge over a four-day period, from 9 degrees above normal Friday to 10
degrees below normal Wednesday. And then another temperature pattern reversal sends
temperatures upward, ultimately carrying readings into the 70s by about Oct. 5.

WINDY, RAINY WEATHER ON EASTERN SEABOARD

Two weather systems, an unnamed disturbance with semi-tropical characteristics and
Tropical Storm Kyle (destined to become Hurricane Kyle), are sending deluges of
wind-driven rain into the eastern United States from the Carolinas to Maine. Interior
areas of the Southeast, especially the Carolinas, need the rain. They've been
experiencing serious drought conditions since February.

--By Richard Koeneman, WGN Weather Center Meteorologist

Thunderstorm downpours, the first since flooding rains with the remnants of Hurricane
Ike and Tropical Storm Lowell forced area rivers out of their banks, doused sections of
the Chicago area Wednesday afternoon. Hardest hit were the northwest suburbs where
as much as 0.83 inches fell at Hoffman Estates, 0.50 inches at Itasca and 0.40 inches at
Palatine. Though the rains bypassed a majority of the Chicago area, Doppler radar
estimates suggested a few locations may have recorded as much as 1.50 inches of rain.
The most impressive cloud tops soared to heights of 42,000 feet, according to Doppler
radar scans.

The storms followed a fifth day at or above 80 degrees at O'Hare. While O'Hare topped
out at 82 degrees, the area's warmest readings included 88 degrees at New Lenox and
87 degrees at Orland Park and Munster, Ind., according to unofficial measurements
from WeatherBug sensors.

High winds with a mammoth area of low pressure continues battering the East Coast
from Florida to New England Thursday. Tropical forecasters are monitoring two
systems in the Atlantic which may take on tropical characteristics.

BRIEF INTERRUPTION IN CHICAGO'S 5-DAY STRING of 80 DEGREE DAYS-- BUT
MORE 80s AHEAD

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

Temperatures surged above 80 degrees a fourth consecutive day Tuesday, and
Wednesday's predicted 80-degree high may extend the streak to five. The late-season
warm spell is occurring despite the seasonal challenges of shorter days and weaker
sunlight. The warmth caps a month of volatile temperature swings that have produced
an average September 2008 temperature of 66.7 degrees -- equal the 137 year
long-term average, yet 2.5-degrees cooler than a year ago. Not only did the mercury hit
90 degrees on this date last year, Chicagoans enjoyed 10 additional 80-degree or
warmer days before the chill of fall and winter took hold.

Chicago isn't alone in enjoying the warmth. LaCrosse, Wis., recorded its eighth
consecutive 80-degree day Tuesdayaa -- the longest late-season string in 100 years
there.

SPRAWLING ATLANTIC STORM COULD INCLUDE TROPICAL STORM KYLE

With tropical forecasters fearful forma- tion of 2008's 11th tropical storm could occur
at any time, it's worth remembering two tropical storms (Jerry and Melissa) and two
hurricanes (Karen and Lorenzo) developed this week a year ago. Powerful winds and
10-12 foot waves pounded the area from Florida to New England Tuesday.

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

With warm late season weather locked in place into the coming weekend a growing
string of warm inland temperatures through Saturday could tie a half-century -old
record for the greatest number of consecutive late-season 80s here. The current record
was set from Oct. 15-22, 1953 -- a period of eight consecutive days over which a
series of four new daytime record highs were established. Lake breezes and the extent
of any cloud cover in coming days will make all the difference in whether daytime highs
make it to 80 degrees or fall a few degrees shy. Clouds this time of year easily disturb
warming.

The National Weather Service's Climate Prediction Center reports the area of the U.S. in
drought has tumbled. While 30 percent of the country had drought conditions in June,
just over 20 percent was in drought in the most recent report.

FIRST TROPICAL TROUBLES BREWING SINCE HURRICANE IKE

Hurricane forecasters are watching a developing area of low pressure near Hispanola
and fear it may become a depression. Winds of more than 39 m.p.h. would qualify the
system as Tropical Storm Kyle. Early computer forecasts suggest the system could
affect the Mid-Atlantic Coast over the coming five days.

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

Even though autumn begins Monday at 10:44 a.m., Chicagoans will enjoy at least another week of summery weather. Highs should be close to 80 degrees on most days in a week that promises to be mainly sunny and dry. Rain chances increase as cold fronts approach late Tuesday and over the weekend, but with limited moisture any precipitation should be light, continuing the dry pattern that has followed in the wake of last weekend's deluges.
Sunday opened dreary with some clouds and fog, but conditions quickly improved as clouds thinned, paving the way for a sunny 80-degree afternoon. Such was not the case in areas far south and west of Chicago where afternoon thunderstorms brought brief soaking downpours. Downstate Ottawa was doused by 1.3 inches of rain in just 30 minutes, while torrential rain near Fowler in northwest Indiana prompted a flash flood warning.

PUERTO RICAN RAINS COULD SPELL TROUBLE FOR ATLANTIC SEABOARD
Heavy rains are accompanying a tropical disturbance near Puerto Rico. Computer forecasts show this system strengthening into a tropical storm (Kyle) that could impact the East Coast later this week.
--By Steve Kahn, WGN Weather Center Meteorologist

Autumn begins at 10:44 a.m. Monday, but the change of seasons will go largely
unnoticed as the city basks in a summery week highlighted by an abundance of sun
and warmth. Temperatures should approach 80 degrees on several days, especially
inland. Such readings are nearly 10 degrees above the steadily declining seasonal
normals (currently in the lower 70s).

The welcome dry-out after last weekend's deluge is expected to continue. This will
allow the levels of streams and rivers to continue to fall. Isolated thunderstorms could
pop up, with afternoon heating mainly west and south of Chicago on Sunday. A few
more thunderstorms could develop midweek before a cold front, but coverage should
be spotty and rainfall totals light.

AFTER LULL IN STORMINESS, TROPICS SHOWING NEW SIGNS OF LIFE

The Atlantic Basin has been quiet after a tumultuous period, where storms Gustav,
Hanna, Ike and Josephine developed in rapid succession. Now a tropical wave in the
northeast Caribbean shows potential for developing into Tropical Storm Kyle. The
system is bringing gusty rains to that region.

--By Steve Kahn, WGN Weather Center Meteorologist

Dry, comparatively warm weather dominates the vast majority of this final weekend of
summer. But, the atmosphere is hardly moisture free. Nearly an inch of evaporated water
hangs in the air over Chicago both Saturday and Sunday. Daytime heating is to increase
the rate at which temperatures decline with height. It’s a situation referred to as an
unstable atmosphere, and it encourages air to rise. With an inland-moving lake breeze
likely to slice into the moderately moist air, it’s not inconceivable a few isolated t-storms
may form. The same process repeats Sunday, but strengthening northeast winds may
force any isolated showers to drift inland to the west or south suburbs in the afternoon.
Rainfall coverage is to be limited.

SIX OF SEPTEMBER 2007’S FINAL 10 DAYS SURGED PAST 80 DEGREES
To date, Chicago has had only three days in the 80s this month, versus 11 a year ago.
--Tom Skilling, Chief Meteorologist, WGN-TV/Chicago Tribune

The final weekend of summer arrives with radically different weather than last weekend
-- though wet soils and a bit of instability may be just enough to prod isolated
thunderstorm development in a few spots Sunday afternoon. Temps are to warm above
last weekend's highs (75 degrees Saturday and 72 degrees Sunday) but without the
huge 8.45-inch rain tally at O'Hare or the 13.06 inches at Crown Point, Ind. -- the
region's heaviest reported.

Friday's high temperature hits 80 degrees for only the fourth time this month and
readings are likely to flirt with 80 degrees again on Saturday. The warmth is welcome in
a month running 2 degrees cooler than a year ago.

Signs of autumn, which arrives officially at 10.44 a.m. Monday, are becoming more
numerous. Fall colors are out and expanding in coverage across the Upper Midwest.

SEPTEMBER'S HEFTY RAINS SLASH SUN 23% FROM YEAR AGO

Though on hold this past week, the month's exorbitant rainfall has slashed Chicago's
September sunshine tally 23% over the same period a year ago. Veteran weather
observer Frank Wachowski reports just 53% of the month's possible sun has occurred
-- well below the normal of 63%.

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

Until Wednesday afternoon's 82-degree high at O'Hare and 83-degree high at Midway,
September had been no bargain for the warm-weather enthusiasts among us. It was
only the third time this month the mercury has reached or exceeded 80 degrees -- the
fewest in a September here since the two recorded in 1993. In 80 years of weather
observations at Midway Airport, September's opening 18 days have hosted eight 80s.
The lack of warm days has occurred with the month averaging 2.5 degrees below the
long-term average -- cool enough to rank among the chilliest 25 percent of
Septembers on the books over the past 138 years at the city's official observation sites.

Wednesday's warmest highs included an unofficial 86 degrees at the WeatherBug
temperature sensor at Orland Park and 85 degrees at Itasca. A wind shift to the
northeast that swept into the area between 3 and 5 p.m. sent temperatures tumbling
from the 80s to the 60s. Warmer weather returns Friday and Saturday.

83 MINUTES OF DAILY SUNLIGHT DISAPPEARS OVER THE NEXT 30
DAYS

Chicago's daily dose of sun has dropped by nearly three hours since days began
shortening June 20. Another 83 minutes vanishes in the next month.

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

The run-off from this past weekend's record-breaking rains is impacting Lake
Michigan. Water levels have risen an inch this month alone, U. S. Army Corps of
Engineers meteorologist Keith Kompoltowicz tells us. It's an increase that has
occurred at a time of the year when lake levels typically fall an inch or two.
Kompoltowicz estimates as much as 877.5-billion additional gallons of water now
reside in Lake Michigan. With September rainfall across the lake's drainage basin 227
percent of normal to date and water from last weekend's rains still working through
tributaries that feed into the mammoth water body, the full impact of the recent
downpours may not yet be fully reflected in lake levels.

Northeast winds Sunday piled water up along the northeast Illinois shoreline
temporarily boosting water levels there 12 to 18 inches .

ERUPTION OF ALASKA'S KASATOCHI VOLCANO BEHIND COLORFUL SUNSETS

Beautiful sunsets worldwide since late August are being attributed to an eruption of
the Kasatochi Volcano on Alaska's Aleutian Islands. Stratospheric winds have
distributed volcanic ash which refracts sunlight producing the array of warm colors at
sunset.

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

It took a rare one-two punch by the remnants of two separate tropical systems to
produce the weekend's one-of-a-kind Midwest deluge. Rain fell in Chicago 48 of the
72 hours between Friday and Sunday and totaled 8.54 inches. There have been heavier
rains outside the city -- among them a 17-inch drenching that hit the west and
southern suburbs in July 1996 centered on Aurora and Naperville. It established a new
24 hour statewide record. But, only once before -- in August 1987 -- has more rain
fallen in a three day period in the city. Moisture associated with landfalling Pacific

Tropical Storm Lowell hit first on Saturday and was followed by Hurricane Ike's
remnants Sunday. The downpour has pushed September's rain tally to 12.61 inches --
a level near seven times normal at this point in the month and four times the full month
norm.

In the wake of the wet weekend, Monday's 63-degree high was Chicago's coolest since
the thermometer hit 62 degrees May 28.

WINTERS FOLLOWING WET SEPTEMBERS SHOW MODEST BIAS TOWARD SNOW

Snow enthusiasts may be encouraged to learn that 7 of 12 winters since 1895 which
followed wet Septembers ended up with more than the long-term average amount of
snow.

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

The remnant low-pressure area associated with Hurricane Ike has moved to northern
New England, but runoff from record-breaking rainfall continues to promote and
prolong flooding along rivers and creeks over northeast Illinois and northwest Indiana.
Greatest area storm totals reported by Sunday evening were 10.48 inches near Crown
Point, Ind., and 10.4 inches in Peotone.
The water has gone down in many neighborhoods, but the Des Plaines River is at record
levels at Des Plaines and Riverside and forecast to remain above flood stage until
Wednesday.
Record flooding along the Little Calumet River in South Holland and Munster, Ind., is
forecast to fall below flood stage Monday evening. Flooding is also occurring along the
Fox River at Dayton, the Illinois River at Morris and Thorn Creek in Thornton and at
many points along the Kankakee River.

AN EXTENDED DRYING-OUT PERIOD
High pressure builds into the Midwest and dominates Chicago weather the remainder of
the week. After today, mostly clear skies with occasional scattered cumulus and cirrus
clouds along with light southerly winds will hold into next weekend. Daytime highs will
be mostly in the 70s and nighttime lows in the 50s.
--By Paul Dailey, WGN Weather Center Meteorologist

Big rains sweep the area this weekend, and flood watches have been hoisted. The waves
of drenching rainfall could deposit 3- to 4-inch totals -- locally more -- which, if true,
would place the multiday rain event among the 11 heaviest in September over 138 years
of records here. This comes in the midst of a September already among the three
wettest on the books. Rain is to hit with two separate systems separated by a pause
Saturday night. The first features clusters of gusty t-storms in warm, humid air
Saturday. Wind-driven downpours follow as the remnants of Hurricane Ike roar by
Sunday.
Ike -- a huge storm more than 500 miles across -- lambasted the northwest Gulf
Coast on Friday. By late morning, 100 m.p.h.-plus wind gusts were being clocked on
offshore oil rigs. And the colossal storm's punishing onshore winds, gusting past 80
m.p.h. on Galveston Island outside Houston, had pushed a 9-foot dome of water across
parts of the coastline -- a storm surge which threatened to grow to 15 to 22 feet --
one of the highest on record in Texas.

SATURDAY'S WARM, MUGGY AIR BRINGS SEVERE THUNDERSTORM RISK
Thunderstorms may grow severe in parts of the area Saturday if any heating at all
materializes.
--Tom Skilling, Chief Meteorologist, WGN-TV/Chicago Tribune

Thunderstorms drenched Downstate Illinois on Thursday and provide a guide on just
how sporadic and thundery rains may sweep the Chicago area from time to time over
the coming days -- hitting hard and fast but limited at any given time to specific
sections of the metro area. The coming rains are likely to include possible downpours
over southern sections of the metro area as Hurricane Ike's remnants sweep across the
Midwest on Sunday into Sunday night. Computer estimates of Chicago's rainfall in the
next three days range from 2 to 4 inches -- but a few areas could get hit by heavier
rains. What's important to underscore as outdoor weekend planning takes place is that
the rains here will be separated by extended dry periods. Moisture content of the
atmosphere exceeds 2 inches Friday night into Saturday, suggesting any thunderstorms
that erupt could include local downpours. Petersburg, Ill., northwest of Springfield, was
hit by 3.02 inches of rain Thursday and nearby Greenview recorded 2.99 inches
underscoring the potential of any subsequent downpours in coming days.

GALVESTON COASTAL RESIDENTS TOLD TO LEAVE OR PERISH AS HURRICANE IKE
THREATENS MONSTER STORM SURGE.

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

With the arrival of noticeably muggier Gulf Coast level 70-degree dew points in the
next day, the atmospheric stage is being set for another rare big September rain. Only
12 times in the past 138 years -- just 9 percent of Septembers on record here since
1871 -- has the month produced three 1-inch-plus rain events. Computer models
boost the air's moisture content (precipitable water) to more than 2 inches Friday into
Saturday. Thunderstorms have the unique ability to sweep moisture from the
environment and concentrate it in especially heavy downpours. This makes projections
of local 2-inch totals from now through Monday in the hardest hit areas look
reasonable. Rain won't be continuous, arriving instead in clusters or waves -- the first
due late Thursday night and early Friday. Saturday's t-storm frequency appears the
greatest of the next three days.

IKE COULD BE REAL TROUBLE FOR HOUSTON/GALVESTON AREAS

A hurricane hasn't hit the Houston/Galveston area since Chantal came ashore in 1989.
The city's last Category 3 storm was Alicia in 1983 -- a devastating $2-billion
Category 3 storm. Ike could give the area and the Texas Coast quite a blow, piling Gulf
water onto the shoreline in powerhouse east winds.

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

Big changes lie ahead. Summerlike warmth and humidity return in coming days.
Readings are headed to 80 degrees Thursday for the first time in 10 days and are likely
to flirt with 80 degrees Friday and Saturday. A multiday 80-degree spell isn't unusual
this time of year. Weather records put odds of back to back 80s beyond this date at 97
percent.

The higher temperatures return with surging humidities -- a set-up which threatens a
new round of heavy rains Friday night into Saturday. More rain involving the remnants
of Hurricane Ike could hit late in the weekend.

RECENT NIGHTS AMONG COOLEST IN EARLY SEPTEMBER SINCE 1997

Warmth has been a no-show of late. Until the recent chill, it's been 11 years since two
consecutive early September Chicago mornings have recorded low temps in the 40s.
Daybreak lows dipped as low as 43 degrees early Tuesday just west of Aurora and in
Rockford. But it was Ogle County's Rochelle -- west of De Kalb -- which logged the
area's chilliest reading of 37 degrees. Weather history suggests the first freezing
temperatures at O'Hare, if this proves a typical meteorological autumn, are still more
than month away.

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

Rains drenched Chicago a second time in just four days Monday, dumping 1.01 inches
at Midway Airport and 1.22 inches at O'Hare International Airport. Monday's dousing
pushed the official O'Hare monthly tally to 4.15 inches, the second wettest in 138 years
and wettest since 1894. Temperatures, which had struggled to reach 67 degrees late
morning, tumbled to the mid-50s as the rain arrived -- levels more typical of
November.

ASTRONOMERS MARVELING AT QUIET STATE OF THE SUN

Only four years ago, sunspots -- the product of intense storms on the surface of our
nearest star -- were at a 1,000 year high. It's been 14 months since the last significant
solar eruption, reports astronomer Dan Joyce. Some in the astronomy community report
the past month has been the first to be free of sunspots in 95 years. Energy from the
sun declines slightly in such periods. The Maunder Minimum, an extended period void
of sunspots in the late 17th Century, may have played a role in a global temperature
decline that caused the Thames River in London to freeze and European harvests to fail.
There is no consensus on how long the current solar lull may last, but some scientists
believe it may end in the next half year.

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

It's going to be a lot more fall-like in Chicago early this week as the city braces for
another round of rain Monday afternoon and night followed by the coolest weather here
since late May.
High temperatures Monday and Tuesday are expected to hold below 70 degrees, and as
chilly north winds arrive in the wake of the rain, overnight lows are likely to drop below
the 50-degree mark for the first time in more than three months.
Heaviest rainfall could approach an inch by Monday night as a strong disturbance
moves through the region.

HANNA DEPARTS AFTER SOAKING THE NORTHEAST; IKE TAKES CENTER STAGE
Tropical Storm Hanna brought a wet and blustery weekend to the Northeast, causing
some flash flooding as up to 6 inches of rain fell in areas around New York City. Gusty
winds downed trees and power lines, but overall damage was minor. Hanna may have
spawned a tornado in Allentown, Pa., Saturday. A funnel was sighted shortly before high
winds partially ripped off roofs and damaged homes in the area.
Hurricane Ike weakened a bit Sunday as it approached Cuba, but it was still packing
120 m.p.h. top winds Sunday evening. Ike is expected to make landfall somewhere on
the Gulf Coast by the end of the week.
--By Steve Kahn, WGN Weather Center Meteorologist

Just days after a thorough soaking by the remnants of Gustav, more rain is headed for
Chicago. Some light showers may develop Sunday, but the city is in line for another
round of significant shower and thunderstorm activity Monday and Monday night as a
cold front pushes through the area. Chilly weather will follow, and low temperatures
may dip below 50 degrees both Tuesday and Wednesday mornings for the first time
since May 29, when the mercury dipped to 42 degrees.

A brief warm-up will boost readings back to around 80 by Thursday, but another cold
front will drop temperatures back to around 70 by next weekend.

HANNA EUROPE-BOUND AS DANGEROUS HURRICANE IKE MARCHES TOWARD FLORIDA AND THE GULF

Tropical Storm Hanna brushed the Eastern Seaboard with gusty winds and heavy rainfall
Saturday. After speeding through the Canadian Maritimes Sunday, it will make a beeline
for the British Isles. Meanwhile, Ike, now a Category 4 hurricane packing top winds of
135 m.p.h., appears headed on a path that will threaten Cuba and southern Florida
before entering the Gulf of Mexico by midweek.

--By Steve Kahn, WGN Weather Center Meteorologist

The cool air mass responsible for Chicago's first back-to-back 60s -- on Thursday and
Friday at Midway Airport -- in nearly 11 years during September's opening five days
dominates this weekend. While both Saturday and Sunday a week ago produced highs
of 90 degrees, peak readings Saturday and Sunday will average 20 degrees cooler.
Those are levels modestly below normal by early September standards. Weak
disturbances embedded in the jet stream will produce several periods in which showers
may flare.
Final rain tallies from Gustav's blustery remnants Thursday approached 3 inches. The
National Weather Service confirms damage in Wheatfield in northwest Indiana was
produced by winds that were part of an EF1 twister that hit the community around 5:30
p.m.

DANGEROUS IKE MAY THREATEN FLORIDA AND ENTER THE GULF OF MEXICO
While Tropical Storm Hanna rapidly spins up the Eastern Seaboard, all eyes are turning
to Hurricane Ike, currently heading toward the Bahamas.
Ike, a Category 3 hurricane packing top winds of 115 m.p.h. Friday night, is expected to
grow even stronger as it steadily churns westward toward Florida and the Gulf of
Mexico.
--Tom Skilling, Chief Meteorologist, WGN-TV/Chicago Tribune

Gustav's blustery remnants lived up to the advance billing Thursday, dousing the
Chicago area with its heaviest official rain in more than five years. By evening,
preliminary totals at the Whitney Young High School Weather Bug sensor had reached
4.12 inches with rain still falling. Other reports included 4.06 inches at Justice, 3.76
inches at Palatine, 3.67 inches at Wilmette, 3.62 inches at Orland Park and 3.51 inches
at Lake Zurich. A rainfall of 4.50 inches hit Downstate at London Mills -- located
between Peoria and the Mississippi River. It marked the first time in three years that the
remnants of a landfalling Gulf Coast hurricane reached Chicago. Hurricane's Rita's
remnants were the last to occur here in 2005.

POWERHOUSE HURRICANE IKE CHURNS TOWARD BAHAMAS; FLORIDIANS
UNEASY

Ragged Tropical Storm Hanna is headed for the Carolinas -- but more ominously,
powerhouse Category 4-intensity (135 m.p.h. peak winds) Hurricane Ike appears
headed for the Bahamas. Some computer models indicate Florida may later be a target
which has residents there on edge. The storm is still five days aways and much can
change. But it's a situation that warrants close observation.

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

Chicago braces for an encounter with Hurricane Gustav's rainy, blustery remnants
Thursday. The storm's impact across the central U.S. has been ongoing since landfall
early Tuesday. Rains in Arkansas on Wednesday alone approached 7 inches at Bee
Branch and 5.89 inches at Jacksonville. The system is responsible for 49 twisters from
Lousiana to Arkansas since coming ashore -- and severe storms are a possibility as far
north as central Illinois and Indiana on Thursday.

For Chicago, Gustav means rain and possibly a good deal of it. Of 26 computer
projections of rainfall here through Friday night, 23 indicated amounts exceeding 2
inches. The average of all estimates topped 3 inches with several in the 4- to 5-inch
range. A tally of 3 inches or more would make this the heaviest official rain event in the
city since 3.20 inches fell on April 30-May 1, 2003.

Since 1900, the remnants of 15 landfalling tropical storms and hurricanes have passed
within 100 miles of Chicago.

2008'S HEAT NOT DONE JUST YET DESPITE COOLER SHORT-TERM
PATTERN

Hot weather -- days with high temps of at leats 90 degrees -- may not be finished yet.
Since 1928, 49 years have produced a 90∞ or higher temp beyond Sept. 4 in Chicago.

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

A million dollar rain is headed for the brown lawns and thirsty crops of the Chicago
area Thursday as a month's worth of rain -- 3.27 inches falls in a "normal" September
here -- rides gusty northeast winds into the area much of Thursday and Thursday
night. The remnants of tropical cyclones -- i.e. tropical storms and hurricanes -- are
finicky and have been known to go overboard in their rain production. Some
Downstate areas could approach or exceed the flood threshold of 5 to 6 inches of
rain in 24 hours. But for the Chicago area, the predicted 2- to 4-inch deluge couldn't
come at a better time. The region has just recorded one of its three driest late
summer spells of the past 138 years. Several storms southwest of the city late
Tuesday unleashed 1.90 inches in Kendall County near Oswego in just 90 minutes.

Subsiding air vented out Gustav's top strengthened warming here Tuesday. The
thermometer at O'Hare hit 94 degrees and Midway topped out at 95 degrees -- the
first such high there in 761 days.

2008 SEASON IN OVERDRIVE; 3 TROPICAL STORMS
WITH HURRICANE POTENTIAL CHURNING THE ATLANTIC!

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

It's been dry in Chicago and in many parts of the Midwest the last several weeks with
much of the Chicago area receiving less than half an inch of rain, making this the driest
Aug. 5-Sept. 2 period since 1933 during the "Dust Bowl."
All that may be about to change: There are growing indications that moisture from the
remnants of Gustav may interact with an approaching cold front to bring an extended
period of rainfall to the area.
Before the rain arrives later in the week, Chicago is in store for another sunny and very
warm day Tuesday. Monday marked the city's fifth official 90-degree high in a
heat-starved summer. It was the warmest Labor Day here since the thermometer hit 95
degrees on Sept. 5, 1983.

STORM BRINGS 117 M.P.H. GUSTS AND 14-INCH RAINS TO LOUISIANA
Gustav spared New Orleans a direct hit, but battered portions of southern Louisiana
with wind gusts as high as 117 m.p.h. and torrential rains that approached 15 inches at
Grand Isle. More than 1 million people were without power Monday evening with the
landscape littered with fallen trees. Gustav spawned at least 17 twisters from the
Florida Panhandle to Louisiana as it made a Labor Day landfall.
--By Steve Kahn, WGN Weather Center Meteorologist