Temperatures on Saturday reached 50 degrees or higher across most of the area. This was the warmest day in Chicago since November 21st, when the official high was 51 degrees. Modest cooling is expected Sunday and Monday as winds turn north to northeast off chilly Great lakes waters. Computer guidance has been very consistent in suggesting major weather changes during the upcoming work week. Intensifying low pressure is forecast to pass west and north of the region on Wednesday, drawing mild, rainy weather into the Midwest, on howling south winds. Polar air massing across western portions of Canada and the U.S. is then forecast to begin spreading east. By Friday, a large amplitude dip in the jet stream is expected to develop, allowing polar air to reach the Midwest. Temperatures next weekend are forecast to remain well below freezing.
Chicagoans haven’t been treated to 40+-degree highs since before last weekend. But that changes Saturday. Gusty southerly winds are to boost temps to their highest levels in 7 days with a 45-degree peak reading not out of the question.
Saturday’s mild spell is to be relatively short-lived—though 40s are to return for a time the middle of next week ahead of a vigorous, new outbreak of arctic air.
Winds are to shift northeasterly off Lake Michigan Sunday, a development expected to reduce temps to levels more typical of seasonal norms this time of the year. The flow off the lake may limit readings to the 30s Sunday and Monday in shoreline locations.
Despite the modest downturn Sunday, this weekend’s temps will far outpace last weekend’s. Saturday’s predicted 45-degree high is to be 19-degrees warmer than last weekend’s frigid 26 and Sunday’s predicted 39 will come in 12-degrees warmer than a week ago.
Black Friday’s 36-deg high—the warmest here in a week—follows single digit morning lows across far west sections of the greater Chicago metro area
Temps here surged to 36-degrees Friday, the warmest in a week. Despite that temp increase, readings Friday fell below seasonal norms an eighth consecutive day. Friday’s normal high was 41-degrees.
Season’s cold finale wipes out early temp surpluses; the autumn 2013 temp trend ends up a statistical “wash”
The books close on November 2013 as well as the three month meteorological autumn season at midnight Saturday night.
Chicago’s average temp for the period will end up a statistical “wash”, finishing with 0.1-degree of normal.
The warmer than normal temps logged in September (+2.7-deg) and October (+0.6-degrees) fall prey to November’s chilly deficit of nearly 3-degrees. The result is the season is to end up with a temperature equaling historic averages.
Fall 2013’s generous sunshine a by-product of the same weather regime which delivered sub-par precip
While fall temps were near normal, the season’s precipitation-production was far from it. A total of 7.78” of water equivalent precip fell during the three month period—an amount 1.73” below normal. That means Chicago’s Sept through Nov precip came in at just 82% normal.
Climate models generate cold December here; Alaska and east Russia warmth aloft a key factor
December 2013, which, along with meteorological winter, gets underway Sunday, will be a cold one if forecasts generated by two key computer models verify.
The European Center’s model is most aggressive with the chill, in terms of its intensity and scope. The model suggests a huge swath of the country as well as a large portion of Canada, is headed into a December likely to produce below normal temps. Montana, the Dakotas and Canada’s Prairie provinces and Rocky Mountain region are predicted to sit within the heart of the month’s frigid air.
The National Weather Service’s climate forecast model known as the “CFS” (for Climate Forecast System Model) is projecting a December chill as well.
Multiple runs of that model, which couples (or links) simulations of the atmosphere with predictions of the planet’s oceans, come to the same chilly conclusion.
The breath of the cold air predicted for December is less extensive than the European Center’s model. But, each machine-generated forecast places Chicago in chillier than normal air overall during the month.
Number of Chicago lows 20-degrees and colder running at more than twice the typical pace to date; only 16 of 143 years have seen more
Black Friday’s early morning O’Hare low of 15-degrees marked the 7th time a low temperature THAT cold has occurred to date this season. That’s twice the normal pace for readings as chilly as that and the greatest number of sub-20-degree lows in Chicago in 18 years. Only 16 of the past 143 years have produced as many cold readings this early in the season.
Potentially record-breaking arctic blast headed into the northern Rockies and Plains next week; Chicago temps to begin tumbling late next week
Cold temp records may fall in the arctic air predicted to hit next week from Montana into North Dakota. The chill is expected to spread eastward, reaching Chicago in weaker form beginning Thursday next week.
The European Center’s global model is putting temps approaching 30-below into sections of Montana and North Dakota by Friday of the coming week.
Weak low pressure is forecast to zip across lake Superior on Saturday. This system will have little impact in the Chicago area, as most of its clouds and precipitation will stay well to our north. Winds are expected to increase from the south and southwest during the morning. This will usher the mildest air into the region since November 21st, when the city posted a high temp of 51 degrees. Late-day temps on Saturday are forecast to range from the low 40s far north suburbs, to near 50 degrees far south. Somewhat cooler air is due to arrive Sunday and Monday, with temperatures averaging near normal for the beginning of December. An influx of mild air is expected midweek, while frigid, polar air masses over the Rocky mountains and High plains. Arctic air is expected to begin moving into the Chicago area late next week.
The chill which has gripped the Chicago area to date has been formidable and unusual. It’s produced the coldest November temps here in 13 years and a string of early season daytime highs the past 6 days which hasn’t been equaled in 63 years.
Temperatures have reached—but not exceeded—34-degrees over that stretch of time, a period in which normal highs are in the 40s.
The last time six days produced highs of 34-degrees or lower this early in a new cold season was 1950.
Strengthening southerly winds Saturday to bring Chicago the first 40s in a week; more 40s due on frontside of a wet storm later next week
Black Friday shoppers will have to bundle up. An 8th consecutive day of below normal temperatures is predicted.
But gusty southerly winds predicted Saturday are expected to boost temperatures into the low 40s for the first time in 7 days. The departure of the strong southerly flow and development of northeast winds off Lake Michigan Sunday is likely to shave several degrees off Chicago’s high temperatures late in the holiday weekend.
Major arctic outbreak indicated later next week; sub-zero cold headed for the northern Rockies and the Dakotas
Far more significant weather changes loom. The season’s most impressive arctic outbreak to date—one likely to send sub-zero temps diving on powerful northerly winds into the northern Rockies and northern Plains next week—is to fan out across a huge swath of the North American continent late next week into the week which follows.
A significant winter storm is to spin-up to Chicago’s west in the process next week—a development likely to send a strong, mild and increasingly moisture-laden southerly wind flow into the metro area, boosting temps Wednesday and Thursday. At the same time, plummeting temps and howling winds on the storm’s backside are to bring a frigid, sub-zero air mass into the country the middle and end of next week.
Southeast then southerly winds develop into the area along with growing rain prospects the middle and end of next week. But the tenacious cold air mass won’t be content to sit to Chicago’s west. Current indications point to a vigorous cold front sweeping across the city and beginning a temp crash Friday and Friday night next week likely to wind up with the area’s lowest readings of the season yet.
Some of the most aggressive computer model temperature projections have temps next week in southwest Canada diving to levels under 30-below in sections of Alberta and Saskatchewan provinces and to well under 20-below in the coldest sections of Montana and North Dakota.
Abnormal arctic warmth aloft in Alaska and Eastern Russia behind the northward buckling jet stream which is setting the stage for the expansive cold surge
The irony of the predicted arctic outbreak is that the cold air’s severity is to be a by-product of a buckling jet stream over Alaska brought on by abnormal arctic latitude warmth. This development leads to a diversion in upper steering winds around the perimeter of the dome of warmth. This northward-buckling in the flow pattern over our 49th state is to sweep unseasonable “warmth” off the much warmer than normal Gulf of Alaska and Pacific ocean, where water temps are running as much as 5 to 6-degrees above normal. The same pattern is to send bitterly cold air diving from interior Alaska into British Columbia, Alberta, Saskatchewan and the northern Rockies.
The cold air is predicted to fan out across much of the Lower 48 later next week, next weekend and the week which follows.
Thanksgiving holiday travelers faced challenging road conditions which slowed traffic to a crawl or a full stop at times Wednesday across the lake from Chicago.
Repetitive waves of snow slashed visibilities to fractions of a mile as they swept off Lake Michigan into the western Michigan and north central Indiana snow belt.
Nowhere did more snow fall than in Berrien County—at the epicenter of Wednesday’s most intense snowfall. It was an area which had been hit hard by lake snow only 2 weeks earlier.
But Berrien County was hardly alone. A multi-county swath, extending from Benton Harbor and South Haven southeast to the South Bend/Mishawaka areas, registered accumulations ranging from 5 to as much as 16”.
Among the heavier snow totals reported were 16.0” in Coloma, MI; 15.0” Spikes Corners, MI; 12.5” Georgetown, IN; 12” at Berrien Center and South Haven, MI; 9.3” Dowagiac and 8” at Mishawaka.
Gusty winds and unseasonably cold, winter-level temps only added to the weather challenges faced by the region.
As all this was happening, Chicago skies Wednesday were sun-filled. But the generous sunshine did little to warm the air.
Not only was Wednesday’s 29-degree high here 13-degrees below normal and the 6th consecutive day to produce a peak reading far below normal, it followed a night of frigid temps—-many in single-digits—across much of the Chicago area west of the city.
Temperatures across the metropolitan area have averaged 11.2-degrees below normal the past six days.
Thanksgiving 2013 could rank coldest in 24 years if daytime highs remain below 32-degrees
If Thursday’s afternoon temps fail to break above freezing, Thanksgiving 2013 may rank the city’s coldest in the 24 years since a 27-degree holiday high in 1989.
It’s Day 6 in the Deep Freeze: Longest string of daytime temps this chilly so early in 76 years (since 1937)
The intensity and the persistence of the recent cold air at such an early stage of the season, is proving unusual.
Thursday will mark the 6th day of high temperatures 34-degrees or colder. That last happened 76 years ago in 1937.
To date, this month’s average temperature of 38.2-degrees—a reading 3.0 below normal— is the coldest recorded in a November here over the past 13 years.
Lake Michigan’s cooled 40-degrees since an Aug 22 high of 77-degrees
The water temperature off the Chicago shoreline reached a seasonal low of 37-degrees Wednesday. That’s a 40-degree reduction from the 77-degree peak water temperature recorded over 3 months ago on August 22.
The Lower 48’s snow cover is the highest for so early in a season since at least 2003
The chill’s not been limited to Chicago. Cold air has permitted the cover of snow across the Lower 48 to rapidly expand. It’s the most extensive snowpack noted this early in the season in the 11 years since detailed analyses of snow coverage began.
On Wednesday, NOAA reported 35.8% of the 48 contiguous U.S. states sat beneath a blanket of snow—more than 5 times the 7% coverage which had been reported just over a week ago.
Models advertising a mammoth cold air outbreak beginning late next week; colder than normal temps to cover much of North America in December’s second week
While temperatures move to a more seasonable level this weekend into next week, computer models suggest an eye-catching pool of colder than normal air may expand to cover the vast majority of North America beginning the end of next week and in the week which follows.
Early indications are temps in the northern Rockies and Plains may plunge to levels nearly 30-degrees below normal with the cold air fanning out to cover a wide area of the country in December’s second week. And, the orientation of the vast cold air pool hints an active storm track may dominate the country.
The predicted cold air outbreak appears linked to a huge, abnormally warm pool of air aloft predicted from Alaska west into Russia. That warm pool is to produce the wavy (amplified) jet stream pattern likely to drive the expansive cold air outbreak.
They’re selective and limited in scope, as lake snows always are. But in the areas affected Wednesday and Wednesday night by the latest and most potent round of early season lake-effect snow this year to date, the accumulations they produce, may range from 6 to as much as 14 inches. They’re to produce trying holiday travel conditions around the southeast end of Lake Michigan—even as sunshine pours down on Chicago and the western shoreline of the lake.
All indicators, including a suite of high-resolution computer model snowfall predictions, place the epicenter of this latest snow event’s heaviest accumulations over Indiana’s LaPorte county and Michigan’s Berrien county. A few of the hardest-hit locations there may see accumulations which top one foot.
The added volume or “fluff” which results from the snow crystal formation process at cold temps like the ones in place Wednesday, mean the day’s strong northwest winds are likely to send some of this snow airborne, producing periods in which there are serious visibility restrictions in the snowbelt.
Powerful East Cast storm driving the strong, cold north winds here
Behind Wednesday’s frigid lake-inducing north to northwest flow into the Midwest is a powerful, north-bound storm sweeping up the Eastern Seaboard.
While frigid northerly winds are blowing here in Chicago and producing local sub-zero and single-digit wind chills as Wednesday gets underway, heavy rains and high winds are pounding coastal cities like New York and Boston. There, temps are mild—but are predicted to take quite a plunge as the storm’s cold backside circulation reaches those areas.
Thanksgiving here in Chicago may be one of—if not THE chilliest—in nearly a quarter century if high temps fail to reach or exceed 32-degrees Thursday, which seems a very real possibility.
Our predicted high temp Thursday is 31-degrees, which would make it the coldest Thanksgiving since a 27-degree high was logged on the holiday in 1989.
Past 4 days have produced the chilliest early-season daytime temperatures in 17 years
Chicago’s high temps over the 4 days since Saturday constitute the city’s coldest early-season chill in 17 years.
While normal highs during the period were in the low and mid 40s, the observed highs at O’Hare have been 26 Saturday (18-deg below normal); 27 Sunday (17-deg below normal); 31 (12-deg below normal) and 34 Tuesday (9-deg below normal)!
With just days left, this month currently ranks as the chilliest November since 2000
November and meteorological autumn are fast approaching their closes. This month is running at the coolest level of any November since 2000—-13 years ago.
The month’s temp this year has been averaging 38.9-deg—a reading 2.5-deg below the long term average. To date, November 2013 ranks 37th coolest of the 143 such periods on record in the city dating back to 1871.
Local 6 to 14” snowfalls aren’t out of the question by late Wednesday night in the hardest-hit sections of the Indiana and southwest Michigan lake snow-belt. The 30-hour lake snow event is predicted to begin in that area late Tuesday with the arrival of strengthening northwest winds with cold arctic air in tow.
Lake snow is light and fluffy. This means the gusty NNW winds predicted to sweep the area late Tuesday, Tuesday night and Wednesday, may well lead to some blowing and drifting of snow.
Storm heading up East Coast to bring balmy rains and t-storms to the big eastern cities before arctic air hits; big snows are targeting areas of New York and Pennsylvania
The powerhouse storm lifting off the Gulf of Mexico and headed northeast up the Eastern Seaboard is the same one which has be-deviled residents of the Southwest and southern Plains in recent days, where it has produced as much as 40” of snow in some of the Utah and Colorado mountains. Arizona and California’s deserts were hit with big rains
The storm is predicted to ride northeastward into Canada, intensifying as it does, turning into a giant wind-maker. It’s backside winds are to force cold, early-season arctic air back into the Chicago area and much of the nation’s mid-section.
In stark contrast, near 60-degree temperatures and heavy rains—some of them possibly thundery— are predicted on the East Coast. There’s even a threat of severe weather in sections of Florida, Georgia and eastern North Carolina.
Chicago records its 6th day with snow Monday; last time that happened was 5 years ago—but it’s not as rare as you might think
A trace or more of snow has fallen in Chicago 6 times to date this season. That’s not as rare as you might think.
It last happened 5 years ago and comparable early season snow trends have been observed through Nov. 26 in 72 of the past 129 years—or 56% of them!
November 2013′s O’Hare snow tally more than the past 5 Novembers put together
O’Hare picked up 0.5” of snow Monday bringing its 2013-14 seasonal tally to 0.9”. It makes this November 2013′s tally larger than ALL of the November snowfalls of the past 5 years combined.
With a frigid Arctic high pressure air mass overhead, this past Chicago weekend saw Saturday-Sunday temperatures 16 and 17-degrees below average respectively – so cold that it was 4 to 5-degrees below average even for our climatologically coldest day in mid-January. A reinforcing cold front will pass through from the northwest later Monday preceded by a band of snow that could end up covering the ground and creating numerous slick spots over much of the metro area.
The leading edge of another Artic high pressure will follow Monday night as winds turn northerly and temperatures will again begin to fall. Northerly flow of very cold air the length of Lake Michigan will establish a lake-effect snow event across northwest Indiana into southwest Lower Michigan – in fact the Illinois shoreline of Lake Michigan could also be impacted, if the wind direction varies ever-so-slightly more to the northeast.
With the blustery north winds creating snow showers and steering another shot of mid-January-like cold into this area, temperatures Tuesday will be lucky to warm much above the 30-degree mark. The core of coldest air settles over the Midwest and western Great Lakes Wednesday – and even with abundant sunshine, highs here will probably be very similar to those experienced this past weekend – in the middle 20s.
Finally the steering upper air jet stream flow will gradually shift from northwest to a more west-east orientation Thursday-Friday, allowing a low-level southerly wind flow – albeit on the weak side – to return. We might even observe normal or slightly above normal readings in the lower to middle 40s this next weekend.
The winter storm in the southern U.S. continues to bring a mixture of rain, freezing rain, sleet and snow to those states in its path. After hitting Texas, Oklahoma and Louisiana Sunday – the wintery precipitation was headed for Arkansas, Tennessee and portions of states just to the south Monday. The storm system was expected to make a turn north up the east coast starting Tuesday.
As Arctic high pressure centered over the central plains holds over our area for the second day – it is likely that Saturday’s high of 26-degrees will be our warmest reading this weekend. These unusual January-like temperatures are indeed a rare event here – a search of Chicago weather records dating back to 1870 indicate that two consecutive days with temperatures less than 27-degrees so early in the season (before November 24th) has occurred only 14 times in the 143-year record.
This frigid air mass has pushed all the way south into Texas and New Mexico. The combination of this cold air with developing low pressure in Arizona has resulted in Winter Storm Warnings and Advisories this weekend for heavy snow in southern portions of Utah and Colorado, to a wintery mix of freezing rain, sleet and snow over a good portion of New Mexico, Oklahoma, and western Texas.
Thanksgiving week in Chicago
The cold air mass will modify somewhat here during the week ahead, but temperatures are still expected to stay below normal until next weekend. High temperatures for the 5-day period Monday through Friday will generally run in the 30s, with the coldest period (highs in the lower 30s) Tuesday and Wednesday. Aside from periodic lake-effect snow showers mainly over the snow belt to our east, the only significant precipitation in the Chicago area looks to be Monday forenoon when a cold front approaching from the northwest is forecast to trigger a band of wet sticking snow that could create some slippery conditions. Thanksgiving day looks to be partly sunny with highs in the middle 30s.
A wintry temperature regime grips the Chicago area this weekend. It’s been 22 years since a set of early season days has produced temperatures as cold or colder than the 27 predicted Saturday and the 25 on Sunday.
Even more dramatic is just how far Saturday’s predicted 27-degree high and the 25 forecast Sunday are to retreat from last weekend’s 61 and 69-degree highs.
Last time Chicago’s daytime readings were this cold so early was 1991
Temperatures as cold as this weekend’s daytime highs last occurred here at such an early date on Nov. 3 and 4, 1991 when highs of 24 and 25-degrees occurred.
Appearance of the mild “Pineapple Express” on continent’s West Coast and expanding Lower 48 snowpack have put arctic air in play
Several factors are contributing to this unseasonable outbreak of cold weather. The arrival of chilly air in recent days has produced snowfall to Chicago’s west which has, in turn, covered the ground.
NOAA, the parent agency of the National Weather Service, reports that while just 7% of the Lower 48 recorded a cover of snow on Wednesday, the number had grown to 28.2% Friday morning—a four-fold increase!
Cold air thrives over a white and therefore highly reflective surface such as snow cover, because as much as 80 or 90% of incoming sunlight is reflected back to space when snow’s present.
The increasingly snowy national landscape in conjunction with a strong flow of mild, moist air into southern Alaska Friday, are the driving forces behind the plunge of cold air taking place in the Great Lakes region this weekend.