The subject of our natural environment -- its well being versus its degredation, the
sustainability of its resources versus their exhaustion, the changes wrought on the
environment by natural forces and by man's activities, the effects those changes are having on
us and on the millions of non-human creatures with whom we share this planet -- these and
myriad similar issues arrived in the public consciousness in 2008.
It's our prediction that environmental issues will become increasingly important.
Wangari Maathai, the recipient of the 2004 Nobel Peace Prize, once said, "One of the
disadvantages of environmental degradation is that it's a very, very slow process and that, quite
often, the generation that destroys the environment is not the one that pays the price."
It has also been said that we are the stewards of the Earth because, of all the Earth's
creatures, only we are truly aware of the environmental consequences of our actions, and
only we can alter our actions accordingly. If an intelligent being from another world
were to visit the Earth, could we say to him with pride: "This is our beautiful planet. Come
see what we have done with it."
--By Richard Koeneman, WGN Weather Center Meteorologist
EXPLAINER: December 2008 Archives
Computer models indicate the trend of Chicago temperatures over the next seven days is
downward, though viciously low readings are not anticipated, at least when judged by the
standards of late December and early January. The city's temperatures will struggle to
reach the lower 20s this afternoon. Chicago's high temperature on Tuesday -- 40 degrees --
was hardly a "mild" reading, but it's likely that area residents will not experience that
relative warmth again during the next two weeks.
STORM TRACK TO REMAIN NORTH
Chicago's weather through the weekend is to be dominated by a progression of rapidly
moving, moisture-starved and relatively weak weather disturbances. Three low-pressure
systems are anticipated, each pushing from the northern Rockies toward Lake Superior and
eastward to New England -- and each accompanied by a surge of light snow along that path.
Chicago, well to the south of the primary track, will see only light snow.
PATTERN CHANGES NEXT WEEK
The possibility of a major snowstorm looms for Chicago on Tuesday and Jan. 6.
--By Richard Koeneman, WGN Weather Center Meteorologist
After tickling the 40-degree mark in the afternoon (a reading 10 degrees above the day's
normal high), area temperatures head downward with the arrival of arctic air, gusty
northwest winds and snow flurries Tuesday night. It won't be horribly cold by late-December
standards -- over- night lows are pegged only into the single digits in the outlying areas
-- but subzero windchills will be the rule.
Looking ahead, computer models suggest a moderately cold weather regime for several
days. Moisture-starved disturbances, each with a bit of snow, zip west-to-east across the
region at 48-hour intervals.
RECORD SNOWS BLANKET
PACIFIC NORTHWEST
While Chicagoans and Midwesterners have been coping with their own winter weather
problems, residents of Oregon and Washington have had it a great deal worse.
Snowfall has reached record or near-record levels in 30 of Washington's 39 counties. As
of Monday, Spokane, Wash., has logged 59.7 inches of snow since Dec. 1, a December record.
Pendleton, Ore., has had 32.5 inches versus a normal of 4.8 inches.
--By Richard Koeneman, WGN Weather Center Meteorologist
Chicagoans reeling from a series of disruptive December storms will welcome this week's
transition to a progression of less intense and less extreme -- though equally fast-paced
-- weather systems.
Swollen area rivers will have a chance to drain, though substantially subfreezing
temperatures by midweek may retard the process.
The forecast indicates that three of the upcoming seven days are to be absolutely
precipitation-free. Contrast that with a total of only four dry days in the preceding four
weeks of December in Chicago.
MILD THROUGH TUESDAY, THEN COLDER
Temperatures Monday bounce into the 40s under a mainly sunny sky, but many will find it
unpleasantly windy. Southwest winds gusting well above 30 m.p.h. will create an afternoon
"feels like" temperature of 30 degrees despite an actual reading about 15 degrees above
the daily normal high of 31.
Relatively mild readings carry into Tuesday, but sharply lower temperatures and a little
light snow arrive late Tuesday. That sets the stage for subnormal temperatures that
persist through year's end.
--By Richard Koeneman, WGN Weather Center Meteorologist
Chicago weather records fell like dominoes Saturday as one of the most bizarre three-day
periods of weather in the city's history came to an end. Since Christmas morning, the
city has weathered severe cold, an ice storm, dense fog, heavy rain, rapid snowmelt, urban
and river flooding, high winds, severe thunderstorms and record warmth. Saturday's high
of 61 degrees at O'Hare tied a 1982 record and the 1.73 inches of rain broke the 1.57-inch
benchmark set in 1942. The heavy rainfall, coupled with the 2 inches of water released
from the rapid snowmelt, not only sent area rivers and streams into flood but caused
flooding of roads and basements throughout the area. The heavy weekend rainfall pushed
Chicago's annual precipitation total above the 50 inch mark for the first time in history.
The city's current (1971-2000) normal annual precipitation total is 36.27 inches.
CALMER WEATHER AHEAD
Temperatures were plunging by late Saturday evening as colder air returned, courtesy of
strong west winds. The year's final days promise to be uneventful with temperatures near
or above normal. The city's next encounter with significant snow should hold off until
New year's night when a "clipper" system could bring some accumulating snow.
--By Steve Kahn, WGN Weather Center Meteorologist
Winter weather systems typically show both warm and cold faces, and the powerful storm
system sweeping across the Midwest today is no different.
This time around, though, Chicago finds itself on the warm side of the storm. That means
rain, and plenty of it today -- perhaps as much as 2 inches. Melting snow will
contribute the equivalent of an additional rainstorm. Widespread flooding will be the result of
all that water.
"ZERO-ZERO" FOG
The perfect recipe for pea-soup fog: mild, moist air and snow cover. Those ingredients
came together across northern Illinois Friday night and are persisting Saturday morning.
The result: Fog so dense that both vertical and horizontal visibilities in the area were
reduced occasionally to less than 100 feet. It is a "zero-zero" situation.
--By Richard Koeneman, WGN Weather Center Meteorologist
The factors that contribute to wintertime river flooding in the Chicago area -- heavy
rainfall, surging temperatures, rapidly melting snow cover and ice-choked rivers -- are
falling into place.
The Chicago National Weather Service has issued a flash flood watch for metropolitan
Chicago from late Friday night through Saturday night, and advises that "major to record
flooding [is] expected this weekend." Computer models suggest that 1 to 3 inches of rain
will fall across the area by Sunday morning -- 1-inch totals most likely toward Rockford and
3-inch totals across southern sections and northwest Indiana.
A period of freezing rain, sleet and hazardously icy conditions is likely early Friday
before temperatures climb above freezing. Warming that continues into Saturday carries
temperatures into the 50s.
ACTIVE THUNDERSTORMS A POSSIBILITY
The interaction between 80-m.p.h. winds aloft and mild, moisture-laden, unstable air
drawn north from the Gulf of Mexico provides a favorable environment for thunderstorms.
--By Richard Koeneman, WGN Weather Center Meteorologist
Chicagoans, made weary by the frequent bouts of harsh weather that have characterized
this young winter season, are about to experience yet another vigorous atmospheric event.
This time around, though, it's to be a surprise on the mild side. Thursday's frigid
readings, biting winds and subzero windchill temperatures yield quickly to comparatively mild
air, clouds, fog and rain that arrives Friday and continues into Saturday. A period of
early ice may precede Friday's rain.
WEEKEND FLOOD THREAT
Temperatures in the 40s, rapid snow melt and potentially heavy rain, even a few
thunderstorms, suggests the threat of flooding on area rivers this weekend.
TSUNAMI REMEMBRANCE
And lest we forget, Christmastime marks the fourth anniversary of a staggering natural
catastrophe: The Indian Ocean earthquake and resultant tsunami that claimed 230,000 lives
in coastal areas around the ocean basin. Residents in affected areas there are still
struggling to put their lives back together.
--By Richard Koeneman, WGN Weather Center Meteorologist
A treacherous mix of snow, sleet and freezing rain that has Chicagoans slipping and
sliding changes over to a final round of snow Wednesday, and several inches may accumulate by
the evening. Temperatures plunge toward zero degrees overnight as a surge of arctic air
sweeps into the city, but the new chill will be brief. Another vigorous storm system
arrives Friday, accompanied by thawing temperatures, fog, copious moisture and heavy rain.
Rapid snowmelt and rain raise the possibility of flooding by Saturday. Christmas Eve in
1983: high minus 11 degrees, low minus 25.
2008: CHICAGO'S WETTEST YEAR EVER?
Following excessive rain and record flooding across the metropolitan area during the
summer and autumn, 2008 year-to-date precipitation as of 7 p.m. Tuesday stood only 0.66
inches short of an annual record. Heavy rain expected Friday and Saturday virtually assures
a new record.
--By Richard Koeneman, WGN Weather Center Meteorologist
It's not often that Chicagoans shiver through a December afternoon with temperatures in
the single digits, but that's what happened Monday. The afternoon temperature struggled
to reach 4 degrees on the city's official thermometer at O'Hare International Airport.
That was the coldest December day since 1989, when the high was just 3 degrees on Dec. 22.
Since records began here in 1870, only 19 December days out of a possible 4,300 have
logged afternoon readings of 4 degrees or lower. Monday was the 20th. The chill eases today,
but the price to be paid is yet more snow in a snowy December that has already seen
three times the normal month-to-date snowfall of 5.7 inches.
CHICAGOANS SHIVER IN THE ICE BOX FOR 29 CONSECUTIVE HOURS
Beginning at 5 a.m. Sunday, and continuing through 10 a.m. Monday morning, the city
was in the grip of a brutal stretch of sub-zero temps. Windchills bottomed out at 33
degrees below zero at 10 a.m. Sunday.
CLOSING IN ON THE WETTEST YEAR
As of Monday, 2008's year-to-date precipitation of 48.56 inches is just 0.79 inches shy
of the 49.35-inch record set in 1983.
--By Richard Koeneman, WGN Weather Center Meteorologist
Northeast Illinois was hit with bone-chilling cold and blizzard conditions Sunday.
Howling west winds gusting more than 40 m.p.h. and subzero temperatures gave life-threatening
windchills of 20 to 40 degrees below zero. In open or rural areas, the winds picked up
and blew the 1 to 2 inches of Saturday's snow, cutting visibilities to near zero and icing
over portions of many north-south roadways. Windchills around 20 degrees below zero
Monday morning will gradually "moderate" to near zero in the afternoon as readings slowly rise
and winds decrease.
NEXT WINTER STORM ON THE WAY
Developing in the Texas Panhandle, low pressure is forecast to move northeast with
leading-edge snows possibly reaching this area Monday night. As the storm approaches, several
inches of heavy accumulating snow are possible over northern Illinois Tuesday.
WHITE CHRISTMAS LIKELY FOR THE AREA
The snow-bearing system should move east Wednesday with a fresh snow cover in place over
Chicago. While Christmas Day will be partly sunny here, a new rain/snow system may
arrive later Thursday night.
--By Paul Dailey, WGN Weather Center Meteorologist
The Winter Solstice occurs at 6:04 a.m., making this the shortest day of the year in Chicago, and it will be by far the coldest this winter. With temps in the single digits and winds gusting at times in excess of 40 m.p.h., dangerous wind chills -20 to -25 degrees will hold over the area today and tonight. Frostbite and hypothermia are a very real threat unless proper precautions are taken. The frigid high pressure air mass will begin to weaken Monday night.
TEMPERATURES MODERATE MIDWEEK
By Wednesday, temperatures are to reach more seasonable levels (Normal high: 33°). Even so, there is a good chance Chicago's snow cover will persist through Christmas.
Winter-weary Chicago-area residents, witnesses to two winter storms in the past week and
to the 13th snowiest open to a cold season since 1884, are headed for another wintry
meteorological blow in the coming 24 hours.
Brutally cold air is on the move and is to pour into the area Sunday and Monday. After
lake-enhanced flurries from extensive clouds Saturday, a period of light snow with
possible 1-2 inch accumulations Saturday night is to be followed by the onset of howling
west/northwest winds expected to gust to 30-40 m.p.h.
Temperatures dive into the single digits before daybreak Sunday and are unlikely to
recover as Canadian high pressure keeps the chill coming. Windchills are to be dangerous --
even before the sun rises Sunday and then well into Sunday night and Monday morning --
dipping into the minus-15-to-minus-25-degree range.
CHICAGO'S HAD ONLY THREE EARLIER SUBZERO LOWS OVER PAST 20 YEARS
The predicted low Monday morning of 7 degrees below zero arrives nearly two weeks early.
What's more, only three of the past 20 years recorded the season's first subzero reading
any earlier.
--Tom Skilling, Chief Meteorologist, WGN-TV/Chicago Tribune
The storm pounding the Chicago area as Friday dawns arrives with quite a history. Its
uncharacteristically heavy early-season snows in the mountains near Los Angeles, San Diego
and Phoenix, and its production of the biggest snow in Las Vegas in nearly three decades
were early warnings the system was packing quite a punch.
A potent collection of meteorological ingredients is in place -- including the arrival
of a rare pocket of 180 m.p.h. jet stream winds that is vigorously lifting the air. The
feature has contributed to overnight thunderstorms that may continue into Friday evening,
producing especially heavy snowfall over the northern half of the Chicago area. It's the
second time this week a critical commuting period has been seriously impacted by the
weather. Accumulations are to vary widely -- 1 to 6 inches from Interstate Highway 80 north to
I-88 and 6 to 14 inches to the north, with the heaviest amounts in the counties along
With 13.9 inches of snow already down, this season ranks among the top 13 percent of the
snowiest cold-season opens -- before the expected 6-plus inches of snow from the
current storm is factored in.
--Tom Skilling, Chief Meteorologist, WGN-TV/Chicago Tribune
Chicago's 7th snowiest December in 124 years is about to get even snowier. The second
major winter storm in a week -- this one wetter and stronger -- hits with thunder Thursday
night and Friday morning. Its track will dictate how the cocktail of precipitation it
produces is distributed across the area. Current indications point toward major snow and
sleet accumulations roughly north of Interstate Highway 80 with serious icing -- capable of
snapping power lines and downing branches -- being a problem late Thursday night in the
south. Computer models and various snowfall forecast techniques suggest the storm's 12 to
14 hours of steady precipitation will reach the city between 8 p.m. and midnight.
Estimates of the storm's water equivalent precipitation range from 0.86 inches to 1.75 inches
-- three to six times the moisture generated by Tuesday's system. That could translate to
6 to 14 inches of snow over parts of the metro area -- especially north -- into
Wisconsin. The presence of t-storms may lead to bursts of heavy precipitation.
RARE SNOW SOCKS LAS VEGAS
Two to 6 inches of snow hit Las Vegas Wednesday. The last time that much snow fell there
was in 1979 when 7.9 inches fell.
--Tom Skilling, Chief Meteorologist, WGN-TV/Chicago Tribune
Snow fell steadily for nearly 10 hours Tuesday, producing the season's heaviest official
snowfall tally to date. By late evening, totals were approaching 5 inches at O'Hare,
solidifying the 2008-09 season as one of the 13 snowiest at this early point in 124 years of
weather records. The ill-timed snow crippled Tuesday evening's rush hour, producing
inflated travel times reminiscent of the infamous 1990 Valentine's Day rush-hour storm. Its
9.7-inch tally was nearly twice Tuesday's snowfall, yet each induced gridlock on area
thoroughfares, hampering snow removal.
The cold temperatures Tuesday turned the 0.30 of an inch of precipitation (water
equivalent) into a volume of snow nearly twice that which might have been expected in a warmer
environment. Snow formation is especially efficient at low temperatures which leads to
bigger flakes.
CONCERN GROWS OVER NEXT SYSTEM
An even more potent storm appears to be taking aim at the Midwest Thursday night into
Friday. The Chicago area is to be positioned precariously close to the boundary between ice
and snow in a storm predicted to produce as much four times the precipitation of
Tuesday's disturbance.
--Tom Skilling, Chief Meteorologist, WGN-TV/Chicago Tribune
The brutally cold January-level arctic blast that roared into the area on 40 m.p.h. gusts,
accompanying a 12-hour 45-degree temperature plunge Sunday night, loosens its grip on
the area Tuesday -- but snow is the trade-off. Snow, likely to fall steadily over 10-12
hours and begin between 2 and 5 p.m. Tuesday, is to produce the first 3-inch-plus
accumulations of the season in Chicago and across the southern suburbs. Totals of 3 to 6
inches are expected over most of the area by the time precipitation winds down in
Wednesday's predawn hours.
It's the latest wintry assault on an area experiencing its fourth-coldest December open in
the past quarter century (since 1983).
The wintry weather isn't limited to Chicago. Thirty-six of the lower 48 states were under
winter weather advisories late Monday. Significant snows were falling in mountainous
areas outside Los Angeles, Las Vegas and Phoenix.
Temperatures remained below zero Monday over Montana, all of the Dakotas and most of
the upper Midwest. Monday afternoon's high at Dickinson, N.D., reached only 13 degrees
below zero, setting a new record low maximum for the date.
--Tom Skilling, Chief Meteorologist, WGN-TV/Chicago Tribune
Even though temperatures peaked in the lower 50s across much of the Chicago area
Sunday, clouds and dampness coupled with strong south winds made it feel a lot
colder. The thaw removed much of the area's lingering ice and snow, but that was
quickly replaced by a burst of freezing rain and snow that swept northern Illinois on
Sunday night as a powerful arctic blast sent temperatures crashing more than 35
degrees in just a few hours.
Burlington, Iowa, reached a balmy 62 degrees at 3 p.m. Sunday, but by evening was
glazed by freezing rain with temperatures in the upper 20s.
Monday's daytime readings here should get no higher than the teens. Windchills will be
below zero as west-northwest winds gust in excess of 30 m.p.h.
MORE SNOW AND COLD ON THE WAY
With cold air firmly in place across the area, Chicago is facing at least three episodes of
wintry precipitation this week.
Several inches of snow are expected to fall here Tuesday night, followed by a wintry
mix by late Thursday and another round of snow late Saturday. By Sunday, a strong
arctic surge threatens the city's first subzero weather of the season.
--By Steve Kahn, WGN Weather Center Meteorologist
Readings are expected to surge into the lower 50s by late Sunday, the warmest readings
here since a 52-degree high on Nov. 14. The long-absent warmth will be propelled into
the area on southerly gales that will gust as high as 45 m.p.h.
Some light showers or drizzle will dampen the scene through the day Sunday, followed
by a period of steadier rain at night as a potent cold front approaches.
As temperatures plunge below freezing after the cold front passes late Sunday night,
the rain is expected to quickly change to snow that could accumulate up to an inch by
early Monday, a day that will feature strong west-northwest winds and falling
temperatures. The rapid freeze-up could create icy conditions for the Monday morning
commute.
SERIES OF IMPULSES TO BRING SEVERAL BOUTS OF SNOW TO THE CHICAGO AREA
With cold air back in place, the city faces several more chances for snow. Rapidly
moving impulses threaten repeat bouts of snow late Tuesday into Wednesday, Thursday
night and late Saturday. Several inches are possible with the Tuesday night-Wednesday
system with the threat of more sticking snow later in the week.
--By Steve Kahn, WGN Weather Center Meteorologist
The surging temperatures predicted to sweep into Chicago on powerhouse southerly
winds this weekend are the product of a mammoth winter storm churning across the
Rockies. The system has prompted warnings for snow and blizzard conditions across
sections of 21 states on its cold side. However, its howling frontside winds -- likely to
blow at more than 70 m.p.h. not more than 3,000 feet above the ground later Saturday
into Sunday while gusting above 40 m.p.h. at the surface here -- are to boost
temperatures by Sunday afternoon more than 40 degrees above Friday's single-digit
lows. Sunday highs are to surge into the low 50s.
Fifty-degree temperatures are not unusual here in December. All but 24 of the past 138
years have produced a 50-degree high, and there have been 439 such readings in
December over the term of Chicago weather records since 1871.
NORTHEAST REELING AFTER
DEVASTATING ICE STORM
More than 1 million households across six states from New Jersey to Maine were
without electricity Friday in the wake of a huge ice storm. Officials fear restoration of
power may not come until late next week.
--Tom Skilling, Chief Meteorologist, WGN-TV/Chicago Tribune
The Midwest is in for a wild weather ride over the next three days. The weather of two seasons is to visit the region before the weekend closes. Friday's descent back into frigid arctic air is to be a brief one. The arrival of south winds Friday night initiates a period of rising temperatures. Saturday's strengthening south winds are to propel high temperatures nearly 20 degrees higher than Friday -- levels well above freezing. But the most eye-catching weather changes arrive Sunday. That's when a powerhouse winter storm takes control of the area's weather, promising a real meteorological roller-coaster ride between Sunday and Monday. Chicago, which is to find itself on the the "warm" side of the system at the start, will see 40+ m.p.h. south winds that push temperatures into the low 50s Sunday -- the highest levels in a month! Thunderstorms can't be ruled out Sunday night ahead of a precipitous temperatures crash Monday.
BLIZZARD, WINTER STORM WATCHES HOISTED FROM ROCKIES TO PLAINS AS WINTRY BLAST CRASHES OUT OF CANADA
Nine states are under winter-storm watch conditions through Saturday. Blizzard conditions are expected in Montana.
--Tom Skilling, Chief Meteorologist, WGN-TV/Chicago Tribune
Cold air has thoroughly dominated the past month with 23 of the past 26 days posting below normal temperatures. It's little wonder more snow has fallen in December's opening 11 days than normally falls the entire month at O'Hare International Airport. South suburban areas have been spared a good deal of the heaviest snowfall. But from Chicago to the north and west, snowfall this season is running at nearly twice the normal pace: 9 inches to date at O'Hare versus 5.2 inches. Just 7 inches had fallen at the site by the same time last season. A review of the 19 snow seasons with comparably heavy seasonal snow tallies by now indicates full season snow tallies finished an average of 34 percent heavier than the long-term average -- 48.9 inches versus the 36.6 inches.
HOUSTON RESIDENTS MARVEL AT A RARE SNOW -- THE FIRST IN 4 YEARS
On Wednesday afternoon and evening, Houston was seeing snow -- an infrequent visitor even in winter. It's the first time snow has fallen there in 4 years. Residents had to be surprised at the issuance of a winter weather advisory as temperatures dropped to freezing, causing icy patches on area bridges and overpasses.
--Tom Skilling, Chief Meteorologist, WGN-TV/Chicago Tribune
Chicago recorded its third 2-inch-plus December snowfall Tuesday propelling the city's seasonal snow tally to 8.5 inches -- the third heaviest early season total here since 1980. Rain preceeded the snow -- lots of it. The day's 1.45-inch water equivalent precipitation tally set a new record for the day becoming the heaviest ever on Dec. 9. Had cold arrived earlier, snows that moisture could have generated -- 10 to 15 inches of it -- would have parallelled those recorded in a corridor of Wisconsin and Lower Michigan from north of Madison to Lake Huron. Snow falls there exceeded 12 to 16 inches.
Plummetting temps and 30+ m.p.h.gusts turned untreated roads into skating rinks late Tuesday. Snowfalls ranged from 2 to 4 inches north and west of the city and less than one inch in the south suburbs where rain persisted into the evening.
PATTERN CHANGE TO DELIVER MILDEST WEATHER IN TWO WEEKS THIS WEEKEND
Temperatures may be rising as early as Friday night as part of a new pattern which will see bitterly cold arctic air masses entering the country by way of the Rockies and Plains-much farther west than over the past month. Chicago highs are headed for the 40s this weekend.
--Tom Skilling, Chief Meteorologist, WGN-TV/Chicago Tribune
It's rain -- not snow -- that greets Tuesday morning commuters as the latest winter storm sweeps the area. Despite the fact the metro area's been mired in uninterrupted cold air for a month -- responsible for the 9th coldest December opening in 139 years -- south winds have tapped mild air and temperatures have been rising during the night. The current "warmth" won't last. Cold air returns as winds shift north/northeast Tuesday afternoon changing rain to sleet and snow for several hours late Tuesday and Tuesday evening before ending. Only an inch or two of snow is to accumulate in the immediate Chicago area -- less south -- but as much as 3 inches near the Illinois-Wisconsin line. These totals pale in comparison to the 8 to 13 inches predicted through central Wisconsin and Lower Michigan.
This December's opening week average of 21.8 degrees -- more than 10 degrees below normal -- joins two others since 2005 in being unusually cold -- 2005 (16.5 degrees) and 2006 (18.3 degrees).
The collapse of a ridge aloft over the Atlantic has set the stage for a westward shift in the coldest air in the U.S. It's a pattern expected to bring 40s here Sunday while introducing much larger temps swings in coming weeks.
--Tom Skilling, Chief Meteorologist, WGN-TV/Chicago Tribune
A winter storm watch is in effect for much of Iowa and Wisconsin and areas just to the
north and northwest of Chicago. The first effects of low pressure developing in the
Texas Panhandle will be felt Monday morning over much of the Midwest.
A thin layer of ice may form on sidewalks and roads. As strong southerly winds aloft
pull warm, moist air over the top of subfreezing air close to the ground, light rain or
drizzle forming in the warmer air is expected to fall into the colder air below and freeze
on contact. Scattered sleet showers are also possible. Temperatures rising into the
lower 30s should minimize the ice threat Monday afternoon in most areas.
BRUNT OF STORM FELT TUESDAY
The low is projected to track northeast through southern Illinois and central Indiana
into northwestern Ohio. As the low approaches in the morning, rain should spread
north into Chicago. As the system moves away, rain will change to snow as winds shift
northeast, pulling colder air into northern Illinois while entraining moisture off of Lake
Michigan. A heavy, wet snow could accumulate to several inches over the Chicago area
Tuesday night and early Wednesday.
--By Paul Dailey, WGN Weather Center Meteorologist
Any warming Sunday will be limited by increasing and thickening clouds ahead of an
approaching low pressure system. Snow should spread over northeast Illinois from the
west later in the afternoon and continue overnight. Another inch or so accumulation is
expected on top of Chicago’s snow cover .
SIGNIFICANT SNOW POSSIBLE
Wet accumulating snow could begin later in the day Tuesday afternoon and continue
overnight. Over the Texas Panhandle Monday night, an intensifying jet stream flowing
from the Pacific Northwest is expected to merge with a strong Southern Pacific-origin,
upper-level, low pressure disturbance moving inland off the southern California coast.
A resulting strong storm is forecast to spread rain into the Ohio Valley and a mix of
rain and snow farther north that could change to all snow over Chicago later Tuesday.
Fresh snow and modestly milder temperatures greet residents as Saturday gets under
way. Gusty winds generate windchills cold enough to cancel out a good part of that
temperature increase. Wind- driven overnight snows, the latest meteorological assault
on area residents, are predicted to produce 1- to 3-inch accumulations before tapering
to flurries several hours into Saturday morning. Sporadic flurries follow, though better
organized snow showers may return ahead of a fresh surge of arctic air and powerful
jet-stream winds later Saturday. Arctic air sends readings into single digits over much
of the area before the sun rises Sunday.
Friday's daytime thermometer readings peaked at 18 degrees -- a level more typical of
January than early December. Though cold air is no stranger here this time of year, only
25 years of the past 139 have seen readings as cold as in recent days so early in the
season.
STICKING SNOW SUNDAY NIGHT AND MONDAY; TUESDAY STORM POTENTIAL
More accumulating snow hits Sunday night into Monday morning, and a complex storm
with snow or a mix of precipitation will have to be monitored for Tuesday.
--Tom Skilling, Chief Meteorologist, WGN-TV/Chicago Tribune
The coldest air to grip the Chicago area in more 9 months moves into a second day Friday. The average date on which Chicago's first official single-digit temperature has occurred over the past 138 years has been Dec. 14. Yet many suburban residents will step out into single-digit temps a second consecutive morning Friday, having experienced lows of 4 degrees in De Kalb, 5 degrees in Aurora and 6 degrees in South Elgin on Thursday. Despite sunshine, snow cover -- heaviest to the west -- will restrict warming Friday. Highs will be close to Thursday's peak reading of 22 degrees -- a January-level temperature which was 16 degrees below normal and the coldest daytime reading here since Feb. 20.
The chill comes at the end of a Nov. 8 through Dec. 4 period which has averaged 33.0 degrees -- this area's coldest in 12 years and a reading 4.8 degrees below the 138-year average.
ONLY FIVE SNOWIER STARTS IN PAST 25 YEARS IN CHICAGO
The 4.3 inches of snow on the books as Chicago's official seasonal tally has been topped only five times in the past 25 years. Weather history tells us 90 percent of the city's seasonal snow has yet to fall.
--Tom Skilling, Chief Meteorologist, WGN-TV/Chicago Tribune
The arctic spigot is wide open Thursday. Chicago-area residents are in for a rendezvous with the area's coldest air since a 19-degree high Feb. 20 -- more than nine months ago. Thermometer readings Thursday are likely to rise no higher than the low 20s which, in combination with an 8 to 18 m.p.h. west/northwest wind, threatens to keep wind chills in single digits much of the day.
Near 40-degree temperatures were in place as the precipitation began Wednesday, bringing rain then sleet. That moisture has frozen overnight and area residents will have to be careful on untreated roads and sidewalks Thursday.
The chilly weather extends the colder-than-normal pattern which has dominated for nearly a month. Temperatures since Nov. 8 have averaged 4.5-degrees below the long-term average -- the chilliest such period in eight years (since 2000). It ranks 21st coldest of the past 139 years placing it among the chilliest 15 percent on record.
HEFTIER SNOW WEST AND NORTH INTO WISCONSIN
Snowfall decreased as it moved into Chicago on Thursday producing 1- to 2-inch tallies. Totals in the 3- to 4-inch range were common across northwest Illinois.
--Tom Skilling, Chief Meteorologist, WGN-TV/Chicago Tribune
Winter is off and running! The pattern of regular cold surges -- punctuated by brief temperature rebounds such as the one in progress as Wednesday dawns -- is to continue beyond mid-month. As if on cue, December's arrival initiated a parade of wintry weather systems across the Chicago area. The second such weather system -- armed with 6 to 8 hours of mixed precipitation and likely to reach the city shortly after midday -- threatens to have some impact on the afternoon and evening rush hour. This is not the huge, moisture-endowed system that hammered the area Sunday and Monday. Computer models late Tuesday were even beginning to suggest its heaviest precipitation is to target Wisconsin more directly than the Chicago area. But the disturbance buried Glacier County, Montana, with up to 9.3 inches of snow Tuesday. Precipitation totals are to be far less dramatic here. In fact, precipitation is likely to begin in an above-freezing environment and is to start as rain or a rain/sleet mix. The air should cool expeditiously with the onset of precipitation, switching to sleet and snow. A final period of snow is to occur as the disturbance exits the area early Wednesday. The best estimate is that 1 to 2 inches of snow may accumulate.
--Tom Skilling, Chief Meteorologist, WGN-TV/Chicago Tribune
Southwest winds that take hold this afternoon are to boost thermometer readings. The problem is winds effectively cancel temperature increases by lowering wind chills. The breezes -- 30 m.p.h. at times by late Tuesday -- are likely to all but eliminate the normal overnight decline of temperatures. But, the cold air these winds attempt to displace is denser than the mild air they carry. This forces much of the warmer air up and over the cool air mass. Initially only mid- and high-level clouds are to result from this process. But as Gulf and Pacific moisture reaches the area Wednesday, clouds thicken and ice pellets (sleet) or a sleet-rain mixture will develop, possibly transitioning to snow late Wednesday. There's enough moisture to suggest slippery travel conditions may develop.
A succession of precipitation-producing systems the next 2 weeks, each followed by cold air, is producing generous computer snowfall estimates ranging from 9 inches to as much as 21 inches over the period.
STORM COULD HAVE BEEN WORSE HERE
Had more of Sunday's copious liquid precipitation fallen as snow, Chicago could have been buried by 7 to 11 inches of snow.
--Tom Skilling, Chief Meteorologist, WGN-TV/Chicago Tribune
