March is the month when Chicago begins its transition from winter to spring in earnest,
with normal temperatures on a steady rise (from a high of 41 degrees on March 1 to 52 on
the 31st). March 2009's opening week will mirror this pattern, starting out cold and
blustery with periods of lake-effect snow Sunday, but quickly morphing into a mild, rainy
pattern with highs well into the 50s by next weekend. Before the warm-up, strong north-
northeast winds blowing cold air down the full length of Lake Michigan will set up a
potential for some accumulating lake-effect snow in lakeside counties.
TWISTERS HIT ALABAMA; MAJOR SNOW TARGETS SOUTH AND EAST
A developing storm system brought at least three twisters to east-central Alabama
Saturday. This same storm is expected to bring heavy snowfall to much of the South and East
Sunday and Monday blanketing areas from Alabama, Georgia and Tennessee to New England
including the major cities of the Northeast.
On Saturday, this storm produced more than 9 inches of snow at Salem, Mo., located
southwest of St. Louis. Snow and sleet also fell from Arkansas across western Tennessee and
northern Mississippi.
--By Steve Kahn, WGN Weather Center Meteorologist
EXPLAINER: February 2009 Archives
Record books in Chicago close Saturday night on the coldest December through February
meteorological winter of the past 23 years. The season has averaged 22.1 degrees -- colder
than last winter's 24.8 and well below the long-term average of 26.7. February has been
the least harsh of the three-month season, but Saturday's 30-degree high will fall
nearly 10 degrees below normal.
A modest lake-effect snow setup produces a few flurries Saturday morning as a
better-organized snow system sinks southeastward from Nebraska through Memphis -- with snow
possible all the way to Atlanta. Chicago's lake-snow potential rises Sunday. Winds coming into
the city from the north will travel four times the distance over water as compared to
Saturday and with a much sharper temperature drop as altitude increases -- signs that
lake-snow formation may be more vigorous.
2009'S 1ST 100-DEGREE READING IN U.S.
A sure sign of the upcoming warm season is the nation's first 100-degree-plus reading of
2009, recorded Friday at McAllen, Texas. It was the earliest-ever triple-digit high for
McAllen and beat the old record (set March 6, 1956) by a week.
--Tom Skilling, Chief Meteorologist, WGN-TV/Chicago Tribune
Standing water was everywhere late Thursday in the wake of blinding downpours delivered
by building-rattling thunderstorms. The city's official rain tally at O'Hare Airport had
reached 1.90 inches by 9 p.m. -- an amount well beyond the 110-year-old Feb. 26 record of
0.92 inches. The deluge closed area roads and prompted flood warnings. The rainfall was
more than typically falls in an entire February and becomes the second heaviest February
rain event in 138 years. Midway Airport's 1.60 inches was also a same-day record,
eclipsing the 0.87 inches in 1971.
Plunging overnight temperatures threatened to turn standing water to ice, and motorists
and pedestrians were being advised to approach Friday morning's commute with caution. The
one consolation for many weary of winter was that Thursday's precipitation was liquid
and not 20 inches of snow, which could have occurred at lower temperatures.
LATE SEASON ARCTIC CHILL IN PLACE
March will open on a wintry note Sunday as strong arctic high north of the Great Lakes
sends an icy blast of northeast winds into the Chicago area causing bands of lake-effect
snow showers to develop here by Sunday evening.
--Tom Skilling, Chief Meteorologist, WGN-TV/Chicago Tribune
The Chicago area's biggest precipitation- producer in nearly two months is on its way.
Rainfall commences toward midday and should build in short order into heavy downpours that
may grow thundery late in the day. At the same time, a snowstorm is to wallop an area to
Chicago's north, from the the Dakotas through the Twin Cities into northern Wisconsin
and Michigan.
The new winter storm producing the cocktail of precipitation was centered in Colorado
late Wednesday. It's the byproduct of a 100-degree north/south temperature spread.
Wednesday readings ranged from below zero on North Dakota's border with Canada to the 90s in
southwest Texas.
A shallow layer of cold air has temporarily returned to Chicago and threatens some sleet
or freezing rain at the onset of precipitation Wednesday -- especially in the north and
west suburbs. But a northbound warm front could send 50s back into the city after dark
ahead of a late-night temperature plunge.
AREA TREATED TO WARMTH WEDNESDAY
O'Hare's 54-degree Wednesday high was the city's mildest reading in two weeks and the
warmest Feb. 25 in eight years. Gary reported a high of 59 and New Lenox hit 58.
--Tom Skilling, Chief Meteorologist, WGN-TV/Chicago Tribune
Chicago's temperatures take off in Wednesday's gusty southerly winds -- reaching the
highest levels in two weeks. The warm-up is being driven by the same air mass behind
Tuesday's temperature surge in the nation's mid-section, which saw readings in the 70s in
Nebraska and in the 90s in western Texas, where highs included 94 degrees at Ft. Stockton and
Pecos -- and a record-breaking 90 at Midland.
A major winter storm comes together Thursday and Thursday night in the Plains and
Midwest. Computer models predict 60+ m.p.h. southerly winds from the Gulf of Mexico north to
Illinois by late Thursday -- a flow expected to act as an atmospheric conveyor belt for
moisture. More than an inch of evaporated moisture is to reach the Chicago area.
THREAT OF MORE PRECIPITATION THAN IN A TYPICAL FEBRUARY
With abundant moisture and tremendous atmospheric lift there is a growing potential for
thunderstorms and heavy rainfall. A normal February produces 1.63 inches of liquid
precipitation here and totals from this storm could easily top that amount.
--Tom Skilling, Chief Meteorologist, WGN-TV/Chicago Tribune
It's been five days since Chicagoans have been treated to a temperature above 32
degrees. A subfreezing spell spanning five days occurs this late in the season an average of
once every five years. Coming as it has in the midst of an especially harsh winter, it's
little wonder predictions of 40- and 48-degree highs Tuesday and Wednesday are raising
Chicagoan's spirits. Despite a February weather pattern less extreme than December or January,
the latest stats on the 2008-09 meteorological winter season, which began Dec. 1, rank
it among the city's harshest 12 percent over 139 years of official weather observations.
Temperatures have averaged 21.4 degrees -- the coldest in 23 years -- and Chicago's
current tally of 48.5 inches of snow is the most in the three decades since the infamous Jane
Byrne/Michael Bilandic 1978-79 snow season that ended up producing 89.7 inches.
SOUTHWEST SIZZLES, TUCSON TOPS LIST
While Chicago was locked in a late-winter chill Monday, record warmth covered portions
of the West. Tucson's 91 degrees fell just one degree short of the all-time February high
there. Records also fell at Winslow, Ariz. (76), and Bozeman (61) and Helena (60), both
in Montana.
--Tom Skilling, Chief Meteorologist, WGN-TV/Chicago Tribune
As the jet stream pattern gradually shifts from a northwest to more westerly flow the
next couple days, a cold Canadian high pressure air mass will move east. As a result,
southerly winds will return to the Midwest beginning tonight, and temperatures will begin to
rise Tuesday.
By Wednesday, northeast Illinois will have experienced some 48 hours of south winds, and
much of the snow cover -- especially southern portions -- will have melted. The melt
will accelerate as the air mass becomes more moist and showers develop. Under the right
circumstances, highs on Wednesday could well exceed 50 degrees -- but cloudy skies, scattered
showers and energy spent on melting snow all will work to restrict warming.
COLD AND SNOW RETURN THURSDAY
As a cold front eases through the area Thursday, winds will shift northeast off Lake
Michigan, and a steady light rain will probably change over to snow Thursday night. The
center of coldest air will hold to the north, but Chicago will sit in the southern flank of
the cold high pressure still partially under the influence of low pressure passing to the
south. That low may bring snow here Friday night and Saturday.
--By Paul Dailey, WGN Weather Center Meteorologist
Chicagoans will experience single-digit windchills today as gusty northwest winds usher in a cold Canadian-source high pressure air mass. The sun's impact will be diminished as it reflects off the fresh 2-to-5-inch snow cover in place after Saturday's storm. Winds will diminish Monday as the eastward-moving center of high pressure passes overhead.
By Tuesday, strengthening southerly flow will allow the return of milder air, but clouds will be increasing as low pressure develops in the central Plains and moves this way. Despite clouds and showers, Wednesday could well be the mildest day of the week as southerly winds continue.
SNOW MELTS OFF, THEN RETURNS
Winds shift to the northeast Thursday, but rain should continue, making it a cool damp day and removing any trace of snow cover. However colder air returns later Thursday night with rain changing to snow. Snow ends Friday with cold high pressure holding into the weekend.
The manner in which winter storms produce their snow is often more complex than it
appears to a casual observer. Take the storm in progress as Saturday dawns. The snowfall it
has generated overnight has been warm air advection snow. That's the snow which develops
as the storm's southerly winds force mild, moist air into cold air. Next comes the
storm's dynamically produced snow. That's the snow generated as upper winds exiting a powerful
jet stream wind pocket slow -- a process which also encourages snow formation. To anyone
watching from below, the snowflakes which result look exactly the same. Yet the storm
is producing its snow in very different ways. The third phase of many winter storms --
this one included -- is the lake-enhanced phase. This occurs in the final hours of a winter
storm as lake moisture is swept into its cold backside. Here, especially large flakes
form and, because of their enhanced size, are noticeably different than earlier snowflakes.
Snowfall may decrease or even ebb temporarily Saturday morning as a slot of dry air
common in winter storms shifts across the area. Snowfall resumes toward midday and through
the afternoon amid strengthening winds.
--Tom Skilling, Chief Meteorologist, WGN-TV/Chicago Tribune
Chicago's February snow drought is about to end. Indications remain compelling that a
swath of the Chicago area may be on the way to getting 6 inches or more of snow. Amounts
farther south -- from Morris to Kankakee and Rensselaer -- may be limited to several inches
because of an anticipated lull in snowfall for a time Saturday morning. The storm system
responsible isn't Chicago's conventional 6-inches + snow producer. Racing southeastward
from Canada, the system originates in a region of limited atmospheric moisture. But
computer models and an array of snowfall forecast techniques suggest it will compensate by
taking advantage of strong jet stream dynamics that will lift and cool available moisture to
produce clouds and snow. A modest injection of lake moisture appears a good bet
Saturday. The storm's snow accumulation is to be made up of 6-7 inches of "system snow" which
falls fairly steadily over 12 to 14 hours -- and a possible 2-3 inches of added lake
moisture which could boost totals in lakeside counties. Snow showers could linger into Saturday
night.
February is historically Chicago's third snowiest month, but has logged 0.8 inches. A
year ago, 14.8 inches had fallen to date.
--Tom Skilling, Chief Meteorologist, WGN-TV/Chicago Tribune
Travel was a nightmare Wednesday over sections of the area as snow combined with
plummeting temperatures to coat many thoroughfares from Rockford into Chicago's
west and northwest suburbs with ice. Conditions became so treacherous that a section
of Illinois Highway 25 in Carpen- tersville and a stretch of Randall Road in Geneva and
St. Charles had to be closed after a rash of accidents and spinouts. Snowfall reached
0.6 inches late Wednesday at O’Hare and Midway—the month's heaviest single-day
tally and the most significant snow since 1.9 inches on Jan. 28.
Until Wednesday, only 9 other Februaries over the past 124 years had produced so little
snow through mid-month. The snow drought didn’t last. Seven of those 9 Februaries
were followed by significant snowfalls (4 inches or more) before the snow season
ended. Typically a quarter (27%) of Chicago's seasonal snow falls after Feb. 19—and a
significant accumulation appears headed this way Friday night into Saturday.
SINGLE-DIGIT WINDCHILL THURSDAY
Thermometer readings struggle to escape the teens as gusty winds limit windchills to 4
degrees below zero to 6 degrees while delivering lake snow showers to portions of the
Indiana/Michigan snowbelt.
--Tom Skilling, Chief Meteorologist, WGN-TV/Chicago Tribune
Wednesday opens with south winds blowing and Chicago in the "warm sector" of a
storm that swept 70s into Kansas and Oklahoma on Tuesday. That mild air in
combination with an influx of Gulf moisture and a fairly steep decline of temperatures
early Wednesday threatens to set the atmospheric stage for some thunderstorms. But
the warmth won't last long. Arctic air is on the move. A late season cold blast sends
temperatures diving Wednesday evening in what is to become the Chicago area's
coldest outbreak in two weeks—since 17 and zero-degree temperature extremes Feb. 4.
While longer days and more direct sunlight takes a bit of the edge off late winter cold
spells, Thursday’s chill is to be impressive. Daytime temperatures will be 15 degrees
below normal with single-digit wind chills.
ONLY 9 FEBRUARYS IN PAST 124 YEARS WITH SO LITTLE SNOW
Only modest snows are predicted as the cold air arrives Wednesday night. Some 1- to
2-inch totals aren't out of the question over portions of the area. More impressive
snow may occur Friday night into Saturday. Until then, February 2009 continues as one
of the nine least snowy to date in 124 years. Only 0.2 inches is on the books.
--Tom Skilling, Chief Meteorologist, WGN-TV/Chicago Tribune
In a winter that more often than not has kept arctic outbreaks and snow coming,
February's weather has offered a bit of a reprieve. Not only has the month averaged temperatures
4 degrees above normal, it's running 4.5 degrees milder than the same period a year ago.
February snowfall has been a fraction of December's ( 21.9 inches) and January's (21.5
inches), totaling just 0.2 inches at O'Hare Airport. A normal February sees 8.3 inches of
snow -- more than 40 times this month's tally to date. But as any longtime Chicagoan will
tell you, winter snows are fickle. Nearly a third of Chicago's seasonal snow has fallen
beyond this date and forecasters are monitoring two systems for possible accumulations.
The storm responsible for 3-inch rains in California on Monday (a storm which prompted a
special marine warning in San Francisco Bay and brought 2 feet or more of snow to the
mountains surrounding Los Angeles) is the first under scrutiny. Forecasters are anxious to
see how computer projections of the system evolve once it moves into the land-based U.S.
weather balloon network. The system appears to have the potential to produce sticking
snow in Chicago later Wednesday. A second lake-enhanced snow could reach Chicago Friday
night into Saturday.
--Tom Skilling, Chief Meteorologist, WGN-TV/Chicago Tribune
High pressure holds over Chicago today; but as it moves east Tuesday, winds strengthen
from the south and clouds increase rapidly from the west. Meanwhile, low pressure will
produce heavy snow in the southern Rockies then move into the central Plains on Tuesday.
That system is projected to intensify as the center of lowest pressure tracks through
northern Illinois on Wednesday. As a result, Chicago's temperatures will rise, probably warming
into the 40s despite the thickening and lowering cloud cover. Rain could begin Tuesday
afternoon, possibly becoming heavy at times as showers -- maybe thunder -- develop Tuesday
night and Wednesday morning. Wednesday looks to be very stormy from the Great Lakes to
the Gulf of Mexico, with heavy snow in Wisconsin and severe storms south of the Ohio
River. Chicago will experience falling afternoon temperatures as rain changes to wet, sticking
snow.
MUCH COLDER AFTER WEDNESDAY
Chicago temperatures will stay below freezing Thursday to Sunday as cold Canadian-source
high pressure is reinforced after a second snow-producing low pressure Friday.
--By Paul Dailey, WGN Weather Center Meteorologist
The week ahead in Chicago will start and end on a cold note -- a sign that winter is not
yet ready to relinquish its icy grip on the city.
After a week of bare ground, a light snow covered the area Saturday. The ground should
remain at least partially snow-covered into Tuesday before temperatures surge into the
40s, triggering a rapid departure of any remaining snow.
MIDWEEK STORM SYSTEM TO START RAINY BUT END SNOWY
That warmth will arrive ahead of a vigorous storm system slated to pass south of the
city through central Illinois. The storm will start out as a rain producer Tuesday night,
but as colder air feeds back into the city on gusty northeast winds on the system's western
flank, the precipitation should quickly change to snow on Wednesday. Several inches of
snow could accumulate before diminishing to flurries late in the day.
The rest of the week will take on a wintry feel with highs in the 20s and 30s. Some snow
is possible as a weather disturbance moves through the area Friday night and Saturday
and more lake-effect snow will occur in the Michigan and Indiana snowbelts.
--By Steve Kahn, WGN Weather Center Meteorologist
The ground is covered with snow for first time in a week. Only a week ago, readings were
headed to near 60 degrees here -- a development which brought an unceremonious end to
the longest-lasting winter snow cover in eight years. For 32 consecutive days, an inch or
more of snow covered the ground. The storm system responsible for Chicago's overnight
snows walloped sections of Nebraska and Iowa on Friday. Nebraska totals included 10 inches
at North Platte and Calloway and 8 inches at Omaha, while 7.1 inches fell at Des Moines.
Though the system was weakening as it swept toward Chicago, it generated 3 inches of snow
near Freeport and 2 inches in Rockford by late Friday evening, producing numerous
accidents.
Until Friday, this month's lack of measurable snow during its opening 12 days in Chicago
was in stark contrast to the 14.5 inches that fell during a comparable February period a
year ago.
Cold north winds travel down Lake Michigan late Saturday night into early Monday and
threaten to provoke lake-effect snow showers in the Indiana snowbelt. A few flurries may
even swipe the northeast Illinois shoreline. A stronger storm is being monitored Tuesday
night into Wednesday.
--Tom Skilling, Chief Meteorologist, WGN-TV/Chicago Tribune
Chicago's first measurable snow in more than two weeks may whiten the ground in time for
Valentine's Day (Saturday). It's true that Indiana's snowbelt was lambasted by one of
the biggest lake snows in decades in February's opening days, but that snow bypassed
Chicago. Not since Jan. 28, when 1.9 inches fell at O'Hare International Airport, has a
measurable snow (0.1 inch or more) occurred in the city. It's been 11 years since a February has
reached its 13th day with so little monthly snow on the books.
The incoming snow is being handled inconsistently by computer models -- not unusual in
developing weather situations. But, an average of all model predictions of this system in
recent days suggests as much as 2 to 4 inches of snow may fall here over a 6- to 10-hour
period beginning late Friday. Several lake effect flurries may precede that snow as early
as Friday afternoon. Winds may become favorable for additional lake-effect snow Sunday
into Monday.
WINTER'S 'COLD RANKING' SLIPS
Recent mild temperatures have slashed Chicago's winter temperature ranking from 10th to
20th coldest. Readings since Dec. 1 have averaged 20.9 degrees -- 5.3 degrees below
average and 4.9 degrees colder than a year ago.
--Tom Skilling, Chief Meteorologist, WGN-TV/Chicago Tribune
Downpours Wednesday, the heaviest here since thunderstorms swamped the area with nearly
2 inches of rain Dec. 27, set a record at O'Hare. The 0.83 inches there blew past the
previous Feb. 11 record of 0.70 inches recorded 129 years ago. Other area totals included
1.23 inches at Valparaiso, Ind., 1.08 inches at Romeoville, 0.85 inches at St. Charles and
0.78 inches at Oak Brook. Downstate Illinois bore the brunt of Wednesday's storm. There,
t-storms erupted near Homer in Champaign County producing 60 m.p.h. wind gusts. Rains in
the region were heavy and included 4.11 inches at Hidalgo, 4.00 inches at Effingham and
3.10 inches at Vandalia.
Sunshine's return Thursday and Friday belies the development of a stormier, more wintry
pattern which may dominate the U.S. much of the remainder of February. A series of storms
embedded within a powerful jet stream roaring off the Pacific are likely to traverse the
U.S. at 3- to 4-day intervals. Among them is a system expected to affect Chicago with
potentially accumulating snow Friday night into Saturday. An average of 38 computer
forecasts suggests as much as 6 inches of snow could render bare ground history here by the
weekend. Lake snow showers may linger into Sunday.
--Tom Skilling, Chief Meteorologist, WGN-TV/Chicago Tribune
It was great while it lasted, but Tuesday's wind-blown 60 degree warmth has vanished as
the city braces for today's heavy rain episode followed by cold and snow in time for
Valentine's Day. Tuesday's balmy highs broke the 60 mark for the first time in 2009. Midway
Airport's 62 degree maximum was the warmest ever there on a Feb. 10, eclipsing the pair of
61 degrees highs reached in 1976 and again in 1999, while the city's official
thermometer at O'Hare International Airport peaked at 61 -- just shy of the record 63 degree high
set in 1876.
Severe weather struck Oklahoma on Tuesday afternoon, producing three damaging twisters
along with highs winds and large hail. One twister did considerable damage in Edmond,
just northwest of Oklahoma City. This same storm system is going to bring heavy rain and
possible flooding to the Chicago area Wednesday as up to 2 inches of rain falls on rivers
swollen by the recent snow and ice melt.
A second storm is expected to bring accumulating snow to the city by late Friday. Early
trends indicate that 3-5 inches could be on the ground here by Valentine's Day.
--By Steve Kahn, WGN Weather Center Meteorologist
A day of record-breaking warmth -- potentially 2009's mildest to date -- sweeps into
the area Tuesday, the product of powerful winds and generous sunshine. Wind trajectories,
which allow the tracking of air mass movement produced by winds, indicate the May-level
60s predicted here had origins not more than 24 hour ago in Louisiana, Arkansas and
Missouri. Record highs Monday -- including 66 degrees Downstate in Springfield, 72 at Paducah
and 70 at Louisville -- occurred within this air mass. Not since a 71-degree high here
three months ago, on Nov. 5, has the Chicago area been treated to warmer temperatures.
There had been two days of 60s by Feb. 10 a year ago, but temperatures of 60 degrees or
warmer this early in the season have occurred in only one of four years since local
weather records began in 1871.
The same storm producing Tuesday's warm winds has coated the Upper Midwest and Plains
with ice and snow. A second storm, responsible for a rare tornado near near Atwater,
Calif., on Monday and for big snows in the mountains of the West -- including 20 inches at
Alpine Meadow Ski resort in California -- next targets the Mid- west late Tuesday night and
Wednesday.
--Tom Skilling, Chief Meteorologist, WGN-TV/Chicago Tribune
Low pressure approaching from the west is expected to spread a brief period of showers
over northeast Illinois this afternoon and tonight. As this band of rain moves to the
east, southwesterly winds will pick up, pulling unseasonably warm air into the area Tuesday.
Chicago's 63-degree record high for Feb. 10 that has stood for 133 years will be tested.
The mild air will also threaten the record high minimum temperature of 43 set in 1886.
Because warm air holds more moisture, showers and thunderstorms could dump heavy rain
before low pressure and the associated cold front Wednesday. Computer models indicate that
as much as 2 inches of rain could fall with these storms, resulting in heavy runoff over
frozen soil and subsequent flooding of already swollen rivers and streams.
TURNING COLDER THURSDAY
For the rest of the week, colder Canadian high pressure will hold over the northern half
of the country, including northern Illinois. This will force low-pressure systems to
track east through the southern portions of the United States and keep Chicago mostly
precipitation-free.
--By Paul Dailey, WGN Weather Center Meteorologist
The city's snowpack, which has covered the ground for more than a month, all but vanished Saturday as the mercury soared into the 50s, bringing the warmest weather here since late December. O’Hare reached 56 degrees and Midway 59, but strong southwest winds sent the mercury to 61 degrees along the lakefront at Northerly Island.The city's official thermometer at O'Hare reached 56 degrees falling short of the day's official record high of 59 set back in 1925, but Midway observer Frank Wachowski tells us that Midway Airport peaked at a balmy 59 degrees establishing a new record high for that site, eclipsing the old record of 53 set in 1965 and tied in 1987. Records tumbled elsewhere around the state including Peoria (65), Springfield (67), Rockford (52) and St. Louis (70).
Cooler weather will return Monday with readings only reaching the lower 40s, but temps rebound sharply on Tuesday as gusty southwest winds should have the city flirting with 60 degrees. The warmth will be followed by some heavy rainfall and even some thunderstorms Wednesday, which combined with added moisture from the melting snow and ice could result in flooding on area streams and rivers.
WINTER RETURNS BY WEEK'S END
Colder air will flood into the region in the wake of the storm, setting the stage for more snow as a series of storm systems parade through the southern states. The first of these could arrive Saturday, making for a snowy Valentine's Day.
--By Steve Kahn, WGN Weather Center Meteorologist
Friday's 41 degrees marked the first time in 2009 that winter-weary Chicagoans have
been treated to an official reading above 40. After the battering Chicagoans have endured
through a parade of arctic air masses responsible for the 9th coldest and 6th snowiest
winter to date of the past 138 years, a day above freezing has become a cause for
celebration. Temperatures have risen slowly overnight and soar 11 degrees higher than Friday this
afternoon, reaching 52 degrees. The reading comes almost six weeks since city was last
treated to a 50-plus-degree high. Melting on Friday reduced Chicago's snowpack 1 inch, to a
depth of just 4 inches, and will end up completely obliterating the 33-day-old snowpack
in coming days. The incoming warmth has origins in the Plains where record-breaking
June-level 80s occurred in Kansas. Garden City's 81 degrees not only set a record, it blasted
past the previous record of 66 set in 1984 by 15 degrees.
WINTRY PATTERN TO RETURN
An often stormy, colder than normal weather regime takes hold after Wednesday and
dominates the remainder of the next two weeks. Typically, 38 percent of Chicago's snow falls
beyond this date.
--Tom Skilling, Chief Meteorologist, WGN-TV/Chicago Tribune
Friday marks the 32nd consecutive day Chicago-area residents have looked at snow covered
ground. It's the longest stretch of snow cover here in 8 years -- and one which is about
to end. Dramatic warming, which sent Plains temperatures as far north as Nebraska
soaring into the 60s on Thursday, is making its move on Chicago. Modest warming sent highs here
to 25 degrees Thursday -- up from 17 the day before. Readings jump another 15 degrees
Friday to 40. But, it's Friday night and Saturday that the most substantial warming is to
get under way. South winds from the Gulf of Mexico increase by Saturday morning to 80
m.p.h at 3,000 feet above the ground here. The set-up is to generate 30+ m.p.h. surface gusts
by late Friday night. As moist air reaches the metro area late Friday the lower
atmosphere will become saturated. Clouds, fog and drizzle will develop quickly. With dew points
-- the temperature at which the humidity is 100 percent -- predicted to rise into the low
40s over the cold, snow-covered surface during the night, the potential for thick fog is
real.
The rapid warming threatens ice jams on area rivers as the run-off from melting snow
hits. It's a formula for river flooding.
--Tom Skilling, Chief Meteorologist, WGN-TV/Chicago Tribune
The final flurries of this week's crippling 30-hour Indiana lake-snow storm fluttered
to earth late Wednesday after burying sections of Porter and La Porte Counties under as
much as 2 1/2 feet of snow. By sunset Wednesday, Burdick -- 5 miles east of Chesterton --
had taken on the dubious distinction as the storm's hardest hit community, reporting an
accumulation of 29 inches. That's nearly 80 percent of Chicago's average full-season snow
tally. Dr. Craig Clark, meteorology professor at Valparaiso University and widely regarded
as the department's winter weather and lake-snow expert, minces no words. He reported
the storm's nearly 2 feet of snow in Valparaiso made it that community's heaviest
lake-effect snow since December 1981.
Thursday is the season's 12th morning of zero or lower temperatures at O'Hare, which
makes this cold season the most prolific zero-degree producer in 25 years. This comes as the
metro area enters its 31st consecutive day under an inch or more of snow. Warming in
coming days -- a slow process at first -- leads to a 50-degree temperature increase by
Saturday afternoon. The day may produce the first 50-degree high here since late December.
--Tom Skilling, Chief Meteorologist, WGN-TV/Chicago Tribune
It was a nightmare scenario for Indiana snowbelt residents Tuesday afternoon and
evening. Lake-effect snow, fluffy by its nature, began falling late Tuesday morning and was
soon airborne in the day's powerful 30-plus m.p.h. gusts. Snowfall became heavy so quickly
that visibilities in Valparaiso -- 50 miles southeast of Chicago's Loop -- had plunged to
less than a quarter mile within an hour of its onset and remained there the rest of the
afternoon. Many areas of Lake, Porter, western La Porte and Starke Counties in northwest
Indiana reported travel-crippling whiteout conditions. Snowfall rates of 3.5 to 4 inches
per hour rivaled the heaviest snows that have fallen in Chicago. By late evening, 12.5
inches had accumulated in San Pierre in Starke County. Other early storm totals included 9
inches at Valparaiso, 7 inches at Michigan City and 6.5 inches north of La Porte -- and
snow was still coming down and expected to accumulate further into Wednesday. Final snow
accumulations could reach or exceed 20 inches in the hardest-hit areas of northwest
Indiana, and widespread totals of 6 to 12 inches were predicted by the time the snow finally
ends late Wednesday.
--Tom Skilling, Chief Meteorologist, WGN-TV/Chicago Tribune
The meteorologically explosive combination of bitterly cold arctic air interacting with
"warmer" lake waters sets the stage for significant lake snow in portions of the Chicago
area Tuesday and Tuesday night. Moisture-laden air hugging Lake Michigan becomes buoyant
in this environment, fostering snow cloud development. The situation threatens to become
a prolific snow producer as north/northeast winds set up the length of the lake and
channel concentrated snowfall ashore. Snowfall will come and go with increasing frequency as
that band oscillates back and forth across eastern Lake, Cook and Will Counties in
Illinois and Indiana's Lake and Porter Counties. Snowfall is likely to be minimal in the western
suburbs that are out of reach of the lake snow. The potential exists for 2 to 4 inches
of snow, with 6 inches in spots, accumulating Tuesday and Tuesday night near the lake.
The heaviest snows shift into Indiana and continue into Wednesday; the extended duration
could produce 6- to 12-inch totals.
The last time the city saw bare ground was Jan. 5 -- 29 days ago. It's the longest
streak since the 63 days that 1 inch or more covered the ground from Dec. 6, 2000, through
Feb. 6, 2001.
--Tom Skilling, Chief Meteorologist, WGN-TV/Chicago Tribune
The Chicago area, locked in a non-stop wintry pattern that brought its 10th coldest
January on record, is finally going to get a break from the cold and snow later this week.
Milder weather will sweep into the area by the weekend, putting a dent in the area's
persistent deep snowpack.
However, before that occurs, the city is facing yet another blitz of snow and cold.
Colder air and some snow will flow into the Midwest late Monday courtesy of strong northerly
winds as low pressure moves into lower Michigan. The trajectory will take arctic air down
the length of Lake Michigan, enhancing the precipitation with lake-effect snow, first in
northeast Illinois and then to northwest Indiana as winds back northwest, bringing
several inches of accumulation. When skies finally clear late Tuesday, readings will plunge --
bringing another night of zero weather to inland areas.
QUICK REBOUND IN TEMPS TO BRING 40s
By Thursday, southwest winds will bring milder air, sending readings Friday to 40
degrees for the first time in 2009. In addition, a weekend rain will help wash away much of the
ice and snow. More rain could arrive early next week.
--By Steve Kahn, WGN Weather Center Meteorologist
