Walt Kelly (1913-1973), creator of the comic strip Pogo, once remarked, "What's good about March? Well, for one thing, it keeps February and April apart."
Kelly understood that March, more than any other month, can manifest the temperature characteristics of both winter and summer. This year, Chicago's March is off to a decidedly wintry start, but big changes are on the way. Daytime highs, six degrees below normal today, will climb to a rainy eight degrees above normal by Sunday.
Meteorological spring begins today
Today marks the start of meteorological spring, the three-month period from March 1 through May 31.
For meteorologists, a season is considered to be a division of the year according to some regularly recurrent weather phenomena. In the mid-latitudes, seasons are based upon the annual cycle of heat and cold; in the tropics (which lack significant temperature fluctuations through the year), seasons are often described in terms of the annual cycle of rain.
-- Richard Koeneman, WGN-TV Meteorologist
February 2010 will soon be history, and if measurable snow does not fall Sunday this month will go into the record books, tied with February, 1967 for the fourth snowiest on record, with a total snowfall of 22.5 inches. In addition to the heavy snow, the month featured virtually no warmth---only one day broke 40 degrees. Since the start of the year, Chicago has recorded only four days in the 40s, and the highest temperature so far in 2010 has been only 46 degrees. The chilly trend will continue through March's opening days but signs of a modest warm-up are visible by the end of the week as readings are expected to climb into the 40. The next storm is likely to bring rain instead of snow.
Cold, snowy February suppresses severe weather
One positive aspect to this nation's cold and snowy February has been a nearly total lack of severe weather. With only one day left in February, not a single tornado has been reported in a month that has averaged 37 twisters since 2000.
It's a first for New Yorkers. Nothing like the parade of megasnows which have lambasted the Big Apple in February has happened before. The latest storm, one of three which have hit the region in just the past month, roared into the city late Wednesday on 30 to 40 mph winds and generated 33 hours of uninterrupted, often heavy snowfall. When the snow finally broke late Friday, New York had been smothered by 21 inches of snow while just across the Hudson River in New Brunswick, N.J., the tally hit an astounding 37 inches. Sparta in northwest New Jersey came in a close second recording 33" of snow. To the northwest in the Catskill Mountain community of Woodridge in southeast New York, an off-the-charts 46.9" of snow had occurred. In effect, more than a season's worth of snow had fallen with a single storm over a day and a half's time. New York City's Central Park February tally of 37" made it the city's single snowiest month ever. The total eclipsed the previous single-month record of 30.5" set in March 1896. Snow records in New York City extend back to 1869.
Storm winds hit 90 mph on New England Coast; 125 mph on New Hampshire's Mt. Washington
Friday's storm was devastating across sections of the mid-Atlantic and Northeast. Nearly a million homes and businesses in a multi-state region extending from New Jersey and Pennsylvania north across New England were without electricity, including 40% of the homes in New Hampshire alone. The huge storm slowed to a crawl Wednesday and Thursday as it became ensnared in an atmospheric blocking pattern. The "block" was produced by a pool of mild air to the north, which generated a stubborn high pressure system which impeded its forward motion. The system was forced to spin in place, sweeping vast quantities of moisture into the region. In the hardest-hit locations of coastal New England, that led to 8" of wind-driven rain which arrived on gusts as high as 90 mph at Portsmouth, N.H. Mt. Washington clocked 125 mph winds. As the moist air swept westward into cold air, gargantuan 3 to 4 foot snows resulted.
Long cloudy spell to accompany Chicago's February to March transition
The storm's circulation transported snow westward into Ohio, Michigan and Indiana late Friday where 1 to 4 accumulations were reported. The westbound snow reached Chicago late Friday evening. A dusting to a half inch was expected Friday night into Saturday morning. The Atlantic moisture driving the snowfall is to hold here into next week and promises to shroud the final weekend of February in clouds with spits of snow and pockets of milder air aloft contributing to the chance of patchy drizzle.
The book on February 2010's weather closes at midnight Sunday night. The month managed a peak temperature no higher than 42 degrees -- making it the first February in 31 years unable to produce a maximum reading that low. By comparison, a 61-degree high was logged last February.
The weather's at it again. In a winter which has taken all sorts of unusual meteorological twists and turns, Friday's sunshine in Chicago appears likely to fall victim to incoming clouds by late in the day. But rather than arriving from the west, Friday afternoon and evening's cloudiness is to sweep in from the northeast. Once here, these clouds are to dominate the coming weekend---the final weekend of meteorological winter---producing periods of light snow Friday night into Saturday. The westward-drifting cloud shield is being generated by the latest mammoth winter storm to hammer the Mid-Atlantic and Northeast.
In New York City, a rain/wet snow mix Thursday morning had transitioned to heavy, wet snow by afternoon. A half foot of water-logged snow had accumulated by late in the day downing some trees along famed 5th Avenue. A falling limb there, snapped by the weight of the snow, fatally injured a pedestrian. New York City's snow was far from over as nightfall arrived. Crippling snowfall is predicted to continue in the Big Apple at least into Saturday morning with accumulations expected to exceed a foot. Visibilities in Central Park late Thursday evening had been slashed by heavy snowfall and howling 30 to 40 mph wind gusts to a quarter-mile.
Farther north, drenching coastal rains riding 40+ mph gusts north of the storm's center along the New England Coast were relentless Thursday. Rain totals in eastern Maine had topped 5 inches by day's end---and rain continued to fall heavily. Once inland, the region's mountains---including Eastern Pennsylvania's Poconos, the Catskills and Adirondacks of Upstate New York and the White and Green Mountains of Vermont and New Hampshire---poked up into the inland-rushing flood of Atlantic moisture changing it to snow. Snow totals there were eye-catching. West Halifax Vermont reported 38.5 inches, Altamont New York 30.5 inches while Kancamagus New Hampshire had 26.0 on the ground---and snow was still falling.
Forward movement of the storm came to a halt Thursday as a blocking pattern developed to its north. Though the system begins weakening slowly Friday, powerful easterly winds on its north side are predicted to force moisture and clouds westward toward the Midwest. The increase in cloudiness predicted in Chicago Friday afternoon and evening, as well as the threat of light snow expected to arrive Friday night are both by-products of the storm and its slow movement.
Chicago in the midst of it 7th snowiest season, February comes in #3 of the past 125 years
Wednesday evening's thundery Chicago area snowburst ended up producing 3.6 inches at O'Hare, enough to push February's tally to 22.4 inches---the third heaviest in 125 years of official snow measurements--- and the seasonal total to 52.3 inches---the 7th heaviest on record since the 1884-85 snow season.
Thursday becomes the first 100 percent sunny day here of the past 44
Sunshine was uninterrupted Thursday. It's the first day in 44 that the city has been treated to 100 percent of its possible sunshine. Only 36 percent of the month's possible sun has occurred in February---below the 46 percent level considered typical this month.
Intense lake-effect snows hit sections of the Chicago metro area hard and fast Wednesday evening with whiteout conditions embedded with flashes of lightning and crashes of thunder, which continued sporadically over several hours. Thunder and lightning occur as air rushes aloft. This upwelling encourages air to sweep into the system concentrating moisture which leads to especially vigorous snowfall.
From Kenosha to Waukegan, Gurnee, Skokie, Mt. Prospect, Oak Brook and Batavia south to Bolingbrook, Ottawa, Joliet and Palos Heights---and, across the city of Chicago---snow fell furiously and accumulated in a matter of just hours to as much as 6 to 8 inches. Late evening traffic slowed to 10 mph on the snow-covered Kennedy Expressway (I-90) and the Reagan Memorial Tollway (I-88). Preliminary totals by late Wednesday evening, with snow still falling at some locations, had reached nearly 8 inches at Gurnee and near Golf and Busse Roads in Mt. Prospect, 6.2 at Beach Park, 6.0 at Zion, 4.3 at Oak Brook and 4.0 at Bolingbrook, Des Plaines and Northbrook.
An inch of snow had fallen at O'Hare by 8:30 p.m. Wednesday, with snow still coming down hard. That was enough to push the city's official seasonal snow tally above 50 inches for the third consecutive year. There's been only one other string of three consecutive 50+ inch seasons in 125 years of snow measurements here and it occurred between 1976 to 1979.
Lake effect snows occur in especially cold environments which, because of the efficiency of ice crystal formation at low temperatures, frequently produce larger than typical accumulations from the limited amount of water vapor available. This leads to snowflakes which exhibit maximum "fluff". Estimates of Wednesday's snow puts snow/water ratios at 30 to 1---indicating the system's snowflakes had almost three times the volume of those which come down in more typical 10 to 1 ratio snow events. One witness, in describing the rate of snowfall in Evanston, compared the scene to a "snow globe." Another described "pure whiteout conditions with snow coming in horizontally" and still another characterized the snowfall intensity at its height Wednesday evening as "this season's heaviest."
A "meso-low" over Lake Michigan--a compact area of low pressure which, when enriched with lake moisture is capable of producing intense bursts of snowfall like those observed here Wednesday evening---first appeared east of Door County Tuesday evening. The system proceeded south the length of the lake Wednesday sending bursts of heavy snow into the Milwaukee area in the afternoon resulting in local 4 to 4.5-inch totals.
Northeast braces for hurricane-intensity winter storm
Barometric pressures over the western Atlantic east of Florida Wednesday were in free-fall. A developing northbound storm system was predicted to intensify explosively before reaching the mid-Atlantic Coast near New York late Thursday and stalling. The storm was behind the maze of weather watches and advisories which had been issued late Wednesday spanning sections of 34 states. New York City, with 30.5 inches of snow on the books this season (17.9 is normal) and Philadelphia with 73.1 (13.8 inches is normal by this date) are among the areas threatened with significant accumulations after a switch from heavy rain to snow. Mountainous areas from Pennsylvania across Upstate New York and New England, may measure snow in feet before this storm finally departs. And powerful east winds on its north side are likely to send clouds and light snow westward as far as eastern Illinois and Wisconsin by the weekend.
Lake-effect snow doesn't happen every day in Chicago. But, when the atmosphere produces a perfect amalgam of small and large scale atmospheric features,the lake snow machine is set in motion. The manner in which snow falls and accumulates in such situations is both fascinating and tricky to predict. Unlike the snowfall attending larger storm systems, which often falls over large areas and with fairly predictable variations in accumulation, the amount of lake snow which piles up in any one location is often influenced by comparatively tiny shifts in wind direction, the length of time over which snow falls, and the intensity with which it comes down, all of which can be modulated by small-scale terrain features like hills or moraines. These can change the amount of "lift" which takes place and that affects precipitation intensity. Areas of increased "lift" maximize precipitation, just as mountains do out West.
That perfect combination of atmospheric appears to be coming together Wednesday and Wednesday night in the counties adjoining Lake Michigan's west and south shores. Northwest Indiana's snow belt may well end up at the epicenter of the developing lake snow episode. If all unfolds as predicted, the hardest hit locations in sections of Lake, Porter and La Porte Counties, as well as in Berrien County Michigan, could be in for 8 to 12 inches of snow---or more. But lake snows are also predicted to sweep onshore in sections of northeast Illinois and eastern Wisconsin. Parts of Cook and Lake County Illinois may be in for 2 to 5 inches snowfalls if early indicators hold together.
A late season blast of cold arctic air, which sent readings tumbling as low as 10-below late Tuesday across sections of the Dakotas and Minnesota, sets the stage for this area's lake snow. Jet streams strengthen as colder air arrives. The "lift" which cools air to saturation and aids in snow development, is especially vigorous beneath the leading edge or strong pockets of jet stream winds known as "jet streaks". When further enhanced as cold air flows over warmer lake waters, the prospects for lake snow take off.
The process was clearly getting underway Tuesday evening as evidenced by falling barometric pressures and the development of a wind circulation east of Door County, Wisconsin. A feature referred to by meteorologists as a "meso-low"---"meso" referring to a medium-sized disturbance, as versus a "macro" or large scale system, was under development and expected to head south over Lake Michigan into Wednesday. Meso-lows in winter, when over large bodies of water have access to moisture that can set bursts of especially heavy snowfall into motion. As this disturbance settles closer to Chicago Wednesday afternoon and evening, the potential for the snowfall to grow heavier and more frequent in lakeside locations may well be enhanced. Just how intense how any resulting snow bursts become will influence accumulation.
Texas hit by snow again; same system could bring eastern U.S. mountains snow measured in feet
The same southward plunge of cold arctic air helped fuel the latest round of snow to hit Texas and the Deep South Tuesday. By evening, the heaviest snow totals in the Lone Star State included 6.0 inches at Sweetwater, 5.3 inches Palestine, 5 inches Baird, 4.4 at Midland (a new record for the date) and 3.5 at Waco. That eastbound disturbance is to proceed off the Florida coast Wednesday where it will begin intensifying explosively. The mammoth storm which results is to continue north then stall over the Mid-Atlantic just north of New York City late in the week and into the weekend. Its slow pace of movement should keep snow piling up across the region prompting the issuance of winter storm watches from Washington D.C. to Philadelphia, Atlantic City and much of interior New York and New England. Mountainous areas there could measure snowfall in feet over coming days---while areas like New York City, where heavy rain is to fall first, are to expected to experience a switch to snow which may produce significant accumulations amid howling winds.
The mammoth system's reach could ultimately extend westward into the Midwest bringing clouds and some periods of light snow to Chicago toward the weekend. Gusty winds here in coming days will be increasingly related to the deep storm's circulation.
Late season arctic chill to bring Chicago its chilliest daytime temps in 10 days
Daytime highs in the 20s Thursday would be the coldest to occur in Chicago since a 28-degree high on Feb. 15.
Even with the clock ticking on February and three month December through February meteorological winter season, Chicago's 2009-10 snow tallies are already among the heaviest on record. And the area's weather history is clear: the snow's not over yet. About a quarter (24 percent) of Chicago's snow takes place beyond this date.
The sporadic flurries, expected to flutter earthward at times in coming days, could become more formidable Wednesday afternoon and night if, as expected, some lake moisture becomes involved. North winds channeling cold late-season arctic air the length of Lake Michigan into Chicago raise the possibility of at least some accumulation Wednesday afternoon and night, particularly lakeside counties.
If true, that's likely to push already impressive Chicago snow numbers even higher. The 18.8 inches of snow on the books through late Monday has created a three-way tie for the 5th snowiest February to-date in 125 years. And the city's seasonal snow total of 48.7 inches ranks 8th snowiest since 1884-85. That's nearly 20 inches higher than the long term average to date and just 1.3 inches short of becoming the third consecutive 50-inch+ season.
Warm temps and weekend disturbances' rapid movement behind less snow than predicted
Predictions of snowfall in Chicago's late weekend storm ended up too high. Mild temperatures impacted the snowflake formation process at cloud level Sunday night shrinking their size. The snow which fell possessed half the volume expected. Measurements of its snow-to-water ratio averaged 6 to 1---i.e. 6 inches of snow for every inch of water---half the typical 12 to 1 ratio. That plus fewer hours of snowfall, because of the system's rapid movement, limited accumulations to 2 to 6 inches---and even less to the south toward Kankakee and Downstate.
Latest U.S. winter storm sweeping Texas
Winter's latest U.S. storm was following the southern route from Arizona and New Mexico into Texas late Monday. Snows beneath that system's northern flank were predicted to reach 1 to 5 inches in the Amarillo area. Three days of snow with the system a mile south of Wolf Creek Pass in south-central Colorado buried that area beneath 45 inches.
Snow is expected to begin Sunday afternoon and spread north, possibly mixed with some sleet in parts of the area near and south of Interstate 80. As the center of low pressure tracks across southern Illinois into central Indiana, snow will increase during the evening hours. A little before midnight will begin the period when snow will fall the hardest in the Chicago area, perhaps as much as an inch an hour in some areas. Travel conditions will deteriorate rapidly and roads will become slick and hazardous. By early Monday morning rush hour, snow totals will probably range from 3 inches far south to over 6 inches on the north side of the metro area. This will be a heavy wet snow with storm total water equivalent in excess of an inch possible.
Cold air follows
As the storm moves east, snowfall will taper off later Monday morning with light snow or flurries continuing into the evening. Storm totals will probably range from 3 to 5 inches south to over 10 inches north. Behind the storm, with a strong northerly jet stream in place, frigid arctic-source air will flow south with the southern edge of this cold air mass pouring over the Canadian border into the Midwest. High temperatures in the middle 20s will be about the best Chicagoans can look forward to Tuesday through Thursday. A cold front could give a period of snow Tuesday night into Wednesday.
A snowstorm with the potential to become one of this winter's biggest appears closer to a rendezvous with the Chicago area. It could spell real trouble for travelers and commuters Sunday night and Monday. The development comes on the heels of a sun-drenched Friday which generated the city's first official temperature above 40 degrees in 26 days. O'Hare topped out at 42 degrees, Midway at 44 and the lakefront 40.
Storm evolution is complex. Much can change as one of these systems bears down on the area. But there's been growing evidence since Thursday evening the incoming storm, which only swept off the Pacific into southern California overnight, is destined to be a formidable precipitation-producer -- capable of generating a swath of heavy, wind-driven snow with accumulations that could reach a foot in at least sections of the Chicago metro area.
On Friday, not one -- but a suite of computer models run by meteorological centers based near Washington DC, Toronto, Canada, and Reading, England -- all produced predictions which shifted the incoming storm's track as much as 150 miles farther north than had been indicated earlier in the week. As noted here Thursday, a northward adjustment in the path of a storm originating over the Pacific isn't unusual. Its predicted path -- which once paralleled the Ohio River -- now takes it across central Illinois and Indiana. It's a shift which greatly increases Chicago's prospects of a direct encounter with its heaviest snowfall. The storm's arrival Sunday night and Monday is likely to come amid strengthening northeast winds.
Gauging its potential snowfall
Forecasters employ a host of techniques in predicting potential snow accumulation. One, which relates snowfall to the change in temperature at 39,000 feet, yields an estimate of 9" with the current storm. Another looks at cloud structure to estimate snowfall. Modern-day computer models generate detailed analyses of the temperatures within snow-bearing clouds. Temperatures in clouds affect snowflake growth and volume and can have a huge impact on just how much snow piles up during a storm. Predictions with the incoming storm suggest an average of 11.7" of snow may fall with each inch of water the system generates. With an average of 0.98" of water predicted to come from this storm, local one-foot accumulations aren't out of the question.
As always with incoming storms, the storm track will prove crucial. One track projection generated Friday had the system on a path across downstate Illinois and Indiana which would send a mix of precipitation -- including possible rain and sleet---into south suburban locations. But late-day forecasts seemed to suggest the zone of mixed precipitation and resulting reduced snow tallies might well occur even farther south. If true, this would place much of the Chicago area in line for the system's maximum snowfall. The impact on morning and evening rush hours Monday and on late weekend travel from the west could be considerable -- and this system warrants careful monitoring.
A big snow Sunday night and Monday could significantly boost this month's already impressive 15.5" tally -- the city's 10th heaviest of the past 125 years up to this point in a February -- potentially propelling it into February's Top 5. But even more interestingly, a snowfall of 10" or more from the incoming storm would make this month one of only two Februarys to produce a set of double-digit accumulations. The only other time this has happened was in February 1896 when a 12.5" and 12" snow were recorded.
Chicago's Saturday snowmaker only a warm-up; dumped 5+" in Iowa Friday
Saturday's snow system is modest compared to the predicted Sunday night and Monday system -- and is just a warm-up for what may lie ahead. The disturbance generated 5.4" in Cumberland and 5" at Greenfield -- both in western Iowa. The 3.7" which fell in Des Moines pushed that city's seasonal snow tally to 61.7" -- one of the five heaviest on record there.
Bring the sun out in February and warming is bound to follow. That was certainly the case Thursday. The day's bright, blue skies, decorated from time to time by a few wisps of cirrus (ice clouds), was for many cause for celebration. Cloud-shrouded February had managed only 33 percent of its possible sun up to that point. The combination of unlimited sunshine and mild temperatures Thursday made it clear to many the march to spring is truly underway.
Area residents were treated to the mildest temperatures in 25 days. Highs hit 41 degrees at Midway and 45 at Chicago's lakefront. Other highs from Weather Bug sensors across the metro area included 43 degrees at Gary, 42 at Winnetka and Oak Lawn, and 41 at Morton Grove, Burr Ridge, Downers Grove and Park Ridge.
O'Hare's official 39-degree high fell just short of 40 and kept the growing string of sub-40 temperatures there going. With only 10 days left in February, Thursday's failure to hit 40 moved the area another step closer to a February without a 40-degree high at the city's official site. Only two Februarys in the past 140 years -- one 1901 and the another in 1978 -- have managed to escape without producing a single 40-degree reading.
Minor snow system due Friday night; more significant storm potential being monitored Sunday night/Monday
Two disturbances -- the first fairly modest in scope, the second capable of growing into a storm Sunday night and Monday -- are being monitored. Each may impact Chicago in coming days.
System one, which on Thursday produced a fresh 6" cover of snow across western Nebraska near Ellsworth, sends a veil of cloudiness streaming across Chicago area skies Friday. It's a development which is to ultimately take a toll on sunshine and, in so doing, probably restrain temperatures to levels a few degrees lower than Thursday -- though still seasonable by late-February standards. An overcast predicted to be in place by evening is to lower and thicken expeditiously Friday night, leading to light snow in the hours beyond midnight. The snow may continue at times Saturday and, because of some pockets of warmer air aloft, may mix with some ice pellets or even a little drizzle.
Potentially more eventful for the Midwest is a second system which threatens to develop into a full-blown winter storm later this weekend into Monday. That system's heaviest snow appears, based on early storm track projections, poised to sock an area from Missouri across downstate central Illinois and Indiana with a significant snow -- potentially a half foot or more.
Chicago doesn't completely escape this system's reach in current forecast scenarios. Its northernmost snows reach the city amid strengthening northeast winds Sunday night into Monday. A series of computer-model snow estimates produces an average around 3" in the city. It's likely there may be lighter totals north in Wisconsin border counties and that heavier amounts could fall across southern sections of the metro area.
But it's early in the storm's life cycle. The system was off the West Coast late Thursday and therefore outside the reach of the land-based U.S. radiosonde (upper-air balloon) network. It's eastward movement carries it into that network, where a more complete scan of its structure will occur, which can be incorporated in future computer forecast model runs. It's not unheard of for the track of storms like this one to be adjusted farther north as this new data becomes available. Such an outcome would allow the storm to impact the Chicago area more significantly. We'll keep you posted!
Februarys as snowy as this one have signaled above-normal snowfall continuing for the remainder of the season
February 2010 is currently the snowiest in 29 years of Chicago snow records. An in-house analysis of seven other snowy Februarys, with an eye toward the trend in snowfall which followed, reveals 5 of the 7 -- 71% of them -- remained snowier than the long-term averages.
Chicagoans are likely to enjoy the sunshine predicted Thursday and Friday. Sun's been in shorter than usual supply in recent days -- in fact much of the month. The metro area has received 25% less February sun than a year ago and 13% less than average. With 15.5" of snow to its credit, February's been the snowiest here in 29 years. It's not surprising such a month would fall short in the sunshine department. To date, only a third (33%) of the month's "normal" sunshine has been logged -- way down from the 58% on the books a year ago. A typical February hosts 46% of its possible sun.
While the Southwest and West are awash in unseasonably mild air, cold air remains in firm control over much of the eastern three-quarters of the nation. Frost and freeze warnings were posted for a second consecutive night across north Florida and are likely to be issued again Thursday night. That area's been shivering in chilly nighttime temperatures, as an atmospheric blocking pattern continues holding cold air in place east of the Rockies.
Florida lows dropped below freezing early Wednesday in Tallahassee (23 degrees), Jacksonville (27), Apalachicola (29) and Panama City (32), and sub-freezing temperatures were predicted a third of the way down the Florida Peninsula overnight.
In marked contrast, residents of the Southwest and West continue basking in unseasonably warm air. Phoenix topped out at 78 degrees Wednesday while downtown Los Angeles recorded 80. The mild air extended north along the West Coast and included a 64-degree high in San Francisco and 51 degrees in Seattle.
Chicago's been snowier than Anchorage, Alaska
The winter 2009-10 pattern across North America, dominated by cold air in the east and mild air far west, has contributed to the production of more snow in Chicago to date (45.4") than the 44.4" thus far in Anchorage, Alaska.
Period of early weekend light snow may be followed by more important Midwest snow-maker
The first of two snowy spells expected to impact sections of the Midwest including Chicago in the coming week is just days away. Light snow may streak into the area for a time Saturday -- but a more substantive snow system is being monitored for late Sunday into Monday. That one's currently off the West Coast but is expected to sweep across the Rockies early in the coming weekend. The track it follows is likely to influence how it distributes its snowfall.
Projections generated by National Weather Service supercomputers late Wednesday hint at a potentially significant snow event centered on central Illinois and Indiana late Sunday into Monday -- but with snows likely to extend north into Chicago where some accumulation may also occur. A more northerly track -- with the center of the system crossing central rather than southern Illinois and Indiana -- could shift that system's most significant snowfall north into the Chicago area. That scenario will be monitored very closely in the days ahead as the Pacific system comes ashore, where its structure can be more thoroughly measured by land-based weather balloons.
45 of the 167 biggest Chicago snows (6"-plus) have occurred beyond this date
About a third of Chicago's measurable snows occur from this point in the season forward. And, of the 167 six-inch or greater snows which have occurred here over 125 years of records here, 45 of them (33%) have occurred from Feb. 18 forward.
The weather pattern dominating North America has an upside-down quality to it. Perennially warm spots are running surprisingly cold while some cold locales are experiencing unprecedented warmth. It was warmer Monday in Anchorage, Alaska, where the temperature hit 44-degrees, than it was here in Chicago with a 28-degree high. Juneau, Alaska's 38-degree low Monday morning was milder than lows of 35-degrees at New Orleans, Louisiana and Daytona Beach, Florida. And to add to the meteorological intrigue, the bursts of snow responsible for half-inch accumulations over parts of the Chicago area Monday, swept into the area from the northeast rather than the west--the typical route snow and other weather systems follow into the area.
Chicago missed the latest significant snow system to sweep the Lower 48 Monday. It buried Ohio and sections of downstate Indiana--- including the Bloomington area---beneath as much as 10 inches of snow, at the same time unseasonably mild weather and an exasperating lack of snow continued to dog winter sports venues at the Vancouver Olympics. Temperatures soared to 53-degrees Monday in Vancouver and to the upper 30s to the north at Whistler, British Columbia, site of a number of Olympic skiing and snowboarding events. The warmest January on record there and the mildest February in 17 years has reduced the typical 80-inch February snowpack to just 35 inches, as more rain than snow has rendered slopes icy and bumpy.
An atmospheric blocking pattern is behind the unusual weather
A blocking pattern which extends from Greenland across northern Canada---the product of a huge pool of comparatively mild air aloft draped across much of the arctic region---shows little sign of relaxing in coming weeks. As a result, chilly weather is likely to hold tight in Chicago. High temperatures Tuesday flirt with 30-degrees---which, while hardly extreme, will fall 5-degrees shy of historic norms, making it the 11th consecutive below normal day. More than half (57 percent) of meteorological winter days (since Dec. 1) have been below normal.
Cold hasn't been barbaric, but it has dramatically slashed the number of mild days
With just two weeks to go in the three month meteorological winter (December through February) period, it's clear the books will close on a colder than normal season this year. Since Dec. 1, Chicago's temperature has run 2-degrees below the long term average. That hardly qualifies as extreme cold. But, the persistence of the chill has had its biggest effect on the season's mildest days. Only six days of 40+-degree "warmth" have been logged to date this season---25 percent of the average 24 days over the past 81 years. There's been only one winter season since 1928 with fewer 40s to date--- 1978-79 with only five 40s by now. Chilly as it's been, it's worth noting that this season has averaged 3-degrees warmer than last.
Cold weather has been the rule in Chicago this month -- not extreme, but persistent. Highs have varied only nine degrees from 26 on Feb. 10 to 35 on Feb. 5. The week ahead promises more of the same, and it is likely that a week from now the city will still not have recorded a 40-degree high by Feb. 21 -- the latest such occurrence in 31 years, when it finally reached 42 on Feb. 23, 1979.
Light snow could bring up to an inch or so of accumulation here Monday into Tuesday as a more significant storm lays a blanket of heavy snow across the southern Midwest into the Ohio Valley. A second storm later this week poses another snow threat, and the city could be on the north edge of the significant totals.
Snow, cold lingers in South
Wintry weather continues across the South with more snow and cold. Winter weather warnings and advisories are posted Monday across a broad area from Arkansas and Mississippi east to Georgia.
Record afternoon cold gripped Florida again Sunday with highs from the middle 50s to lower 60s. Late Sunday afternoon it was warmer at the Winter Olympics in Vancouver, 54 degrees, than at Tampa, 52.
Clouds will be increasing in Chicago on Valentine's day but the weather should be dry until some snow moves in at night, as an unusual southwest push of moisture, having origins over the north Atlantic near Greenland, moves into the area. The snow should begin Sunday night and continue intermittently into Tuesday. While not expected to be heavy, snow could accumulate a few inches with enhanced totals near the lake. A more significant storm, which brought up to 10.5 inches of snow to North Dakota Saturday, will miss Chicago but drop a band of heavy snow from Missouri into the Ohio Valley on Sunday/Sunday night and bring another accumulating snow to Washington D.C. on Presidents Day.
Big chill follows southern snow
Friday's snowstorm in the Southeast is history but it has left a record chill in its wake. Up to 2 inches of snow fell in the Florida Panhandle, while 4 to 9 inches coated areas from Arkansas and Louisiana to the Carolinas and Virginia. High temperatures Saturday were mainly in the 40s. In central Florida, 52 degree record low maximums were recorded at Orlando, Melbourne and Vero Beach.
The extraordinary rash of snowstorms which have swept the U.S. in recent weeks, many generating record snowfall, have produced one of the country's most expansive snow packs in recent memory. National Weather Service researchers charged with monitoring the country's snow cover and its water content estimated Friday that more than 67% of the Lower 48 sat beneath a veil of snow. Hawaii, despite the presence of mountains which can and often do become snow-covered in winter, is the only state not to report at least some snow on the ground. The snow has been so widespread in recent weeks, even perennially snow-free Florida has failed to escape. De Funiak Springs, in the state's panhandle near the Alabama border, reported a 1" snow accumulation late Friday afternoon at the same time a thundery squall line in warmer air to the south was diving southward the length of the Florida peninsula unleashing driving rains and 70 mph gusts.
The meteorological mayhem in the Sunshine State was the product Friday of the same powerful winter storm, which only a day earlier walloped the Dallas/Fort Worth metroplex with an all-time calendar day record of 12 to 14" of snow.
The eastbound system spent Friday burying areas unaccustomed to snow beneath rare accumulations. Up to 8" fell at De Kalb, Miss., while thousands were reported in the dark late Friday across Charleston, S.C., as wind and wet snow brought down power lines. Much of the city's downtown area was without electricity Friday evening. Just west, snowfall reached 7" as night closed in on Columbia, S.C. A motorist in nearby Chapin reported taking an hour to travel just 10 miles. All forms of travel were severely impacted across the Southeast. Heavy snow forced the cancellation of thousands of flights in Atlanta and across the region.
Rapid intensification of the sprawling storm was underway late Friday. A NOAA buoy off the northeast Florida coast 42 miles east/northeast of St. Augustine reported winds which gusted to 52 mph as barometric pressure readings, a gauge of storm intensity, plunged an eye-catching 11 millibars -- from 29.71" to 29.38" in under two hours. The storm is predicted to move out to sea Saturday.
More snow for DC?
A new low pressure drops southeastward through the Plains Saturday and Saturday night, developing a swath of snow from North Dakota southeastward into Missouri and southern Illinois. While this system is likely to remain west of Chicago, it threatens to spin up into yet another snow-producer for the Nation's Capital early next week.
Chicago's next snow due Sunday and Monday
The Valentine's Day weekend is to remain meteorologically quiet for Chicago with plenty of daytime sun Saturday and Sunday and moderately chilly mid-February temperatures. But an unusual southwestward push of moist Atlantic air into Chicago from Canada Sunday night and Monday is to deliver the area's next snow.
While most of Chicago's weather arrives from the west or south, the moisture behind the next snow system has origins over the North Atlantic and the Davis Strait -- which sits between northeast Canada and Greenland. A rare jet stream configuration, which features upper steering winds that flow from the Atlantic westward into the Midwest, is driving the unusual pattern and is to be joined by by north to northeast low-level winds expected to blow into the city Monday off Lake Michigan, potentially enhancing snowfall.
The latest in the this season's parade of record-breaking storms had no sooner exited the mid-Atlantic early Thursday when the snows of the week's second storm---this one on a more southerly track---swept into north Texas and southern Oklahoma. It was to prove one for the books there. By late afternoon, 7.9 inches of snow had fallen on the Dallas/Fort Worth metroplex---more than on any other single day in 112 years of weather records. That total eclipsed the previous record of 7.8 inches first recorded on Jan. 14, 1917---then again on Jan. 15, 1964. And the snow was far from over. By 10 p.m. in Dallas---just five hours later---snow was still falling heavily and the tally had jumped to 9.4 inches. For more than 13 consecutive hours, snowfall was so heavy in the north Texas metropolis, visibilities were slashed to a half mile or less.
The big totals weren't limited to Dallas/Ft. Worth proper. To the northwest in Denton, 12 inches had fallen by late evening and Cottondale, 67 miles to the northwest, was hit by 11.5 inches.
The eastbound storm threatened to spread rare accumulating snows across a wide swath of the Deep South---including New Orleans' northern suburbs, Mobile, Ala. and even Pensacola, Fla., where an inch or two was predicted to stick on grassy surfaces. The full brunt of the storm threatened far heavier accumulations in Jackson Miss. (3-6 inches) and Birmingham Ala. (up to 3 inches). Winter storm watches were up Friday and Friday night for Atlanta and Savannah in Georgia and for Columbia and Charleston in South Carolina.
Quieter pattern for Chicago: Nights frigid but stronger February sun a factor by day
A minor disturbance threatened Chicago with cloudier skies and a few flurries Friday, a big change from Thursday which logged 98 percent of its possible sunshine making it the area's sunniest day in four weeks. Despite Thursday's sub-freezing 30-degree high, icicles dripped and the foot of snow which fell earlier this week continued settling and even melted a bit. The snow depth at Midway Airport slipped from 9 inches to 6 in just a day's time.
Between January and February, sunshine in Chicago doubles in strength. The higher trek the sun follows across area sky allows the delivery of stronger, more direct rays and is the reason chilly air masses don't always feel quite as cold as their late December or January counterparts.
58 percent historical probability of a 60-degree temperature in the coming 30 days
Winter's far from over. Computer models are hinting that although Friday's flurries and the potentially lake-enhanced snow showers predicted to lock in Sunday night into Tuesday, will most likely produce only modest accumulations. That could change in Week #2. Some early projections hint two storm systems could cross the area and possibly produce significant snowfall close to Chicago.
Despite that, it's worth noting that 58 percent of years have produced a 60-degree temperature in the coming 30 days (by March 13)---and that the first 70-degree temperature may be only a little over 40-days away if their arrival dates parallel historic trends.
It seems almost unfathomable in Thursday morning's chill that Chicago's earliest 70-degree temperature occurred 11 years ago---on Feb. 11, 1999. That warm spell, brief as it was,couldn't have come at a better time for winter-weary area residents. Only 5 weeks earlier, the city had been hit hard by a snowstorm which produced the 2nd heaviest snow since records began in the 1884-85 season. (That January 1999 storm, replete with 50+ mph wind gusts, smothered the area beneath 18.6 inches of snow.) The city's first 70-degree reading of the year has occurred on average on or about March 24.
Temperatures at that level are the last thing on the minds of many across the Chicago area Thursday morning. Clearing skies and diminishing overnight winds have allowed temperatures to dive into the single digits and teens---a temperature plunge spurred in part by the presence of the season's deepest snow pack.
Chicago's 2009-10 seasonal snow tally has reached 45.1 inches in the wake of Tuesday's record snow---a total which ranks 9th snowiest of the 125 on the books to date. It's nearly twice the 24.9 inches which has typically occurred by now.
Tuesday's 12.6 inches of snow at O'Hare over becomes the city's single heaviest calendar day February snow on record. The tally also qualifies as the 7th heaviest calendar day snowstorm in over 125 years of observations.
Think snow's bad here? Mid-Atlantic reeling in midst of snowiest season on record!
The Nation's Capital, where schools, businesses and even a parts of the Federal government shut down in blizzard conditions Wednesday, is now home to a deeper snowpack---28 inches of it---than in either Anchorage Alaska (20 inches) or Marquette Mich. (27 inches). The latest snowstorm to hit the Mid-Atlantic generated 10.5 new inches of snow in Washington, D.C. 19.5 inches Baltimore, 14.4 Philadelphia and 12.5 in New York's Bronx Wednesday.
Seasonal snow tallies in the region are stunning. In Washington, where 15 inches falls on average during an entire season, 55.6 inches is now on the books---making this the snowiest season on record. The nearly 20 inches of snow which fell Wednesday on Baltimore in the midst of howling, blizzard-strength winds sent that city's seasonal snow total soaring past 72 inches. Seasonal snow tallies have also reached new all-time highs in Philadelphia, Wilmington DE, and Atlantic City, N.J.
It's now the third consecutive snowier than normal season
Some light snow reaches Chicago again Friday evening and night. But, a new system Sunday night and Monday will have to be monitored for possibly more substantial snows. All of the snow of late has pushed Chicago's seasonal snow above normal for a third consecutive winter.
Snow, which had fallen steadily much of the day at little more than a moderate clip, suddenly intensified late Tuesday. What had been a fairly innocuous late winter snow across the Chicago area through mid-afternoon suddenly took on the trappings of the significant winter storm which had been predicted--particularly in the counties lining Lake Michigan's Wisconsin and Illinois shorelines. Thoroughfares on which road chemicals had worked so well much of the day, quickly covered with snow, rendering them treacherous as night fell.
By late evening, Lake County's Antioch, just south of the Wisconsin line, sat under a fresh 14-inch snowpack while just to the south in Round Lake Heights, a 12-inch snow glistened beneath streetlights, which dimmed as each wave of heavy snow passed. Other snow totals in Mount Prospect (11.3 inches), Buffalo Grove (11.0) and Mundelein (10.5) moved within striking distance of a foot---and totals of 9.6 inches at Beach Park, 9.4 at Oak Brook, 8.3 at Downers Grove as well as the official in-city totals of 8.3 at O'Hare and 7.0 at Midway--seemed likely to surge still higher overnight as late evening snows grew in areal coverage and intensity. Weather radars from Chicago to Green Bay indicated clusters of heavy lake-effect snow were in the process of consolidating into an elongated 260-mile band---extending from east of Door County, Wisconsin south the length of Lake Michigan into northeast Illinois. The feature, referred to by meteorologists as a "lake-snow plume," threatened additional accumulations of snow up and down the western shore of the lake during the night.
Lake snow plumes form as low-level winds converge over warmer lake waters. These converging winds lead to a pile-up of air at the surface which has little option but to rise, cooling and becoming saturated as the lake moisture evaporated in it condenses. Towering clouds form from which locally intense snows fall. With winds guiding these lake-effect clouds southward over lake waters for an extended distance, the chance for moisture to accumulate is huge. The snows which fall at the end of such a long plume of saturated air can be quite formidable---as northwest Indiana residents are to find out much of Wednesday as these lake snows slowly shift east.
Wednesday is to open with the heavy snows of the plume riding into northwest Indiana's Lake and Porter Counties---but shifting gradually eastward to La Porte County by late in the day.
Third consecutive snow season to top historic norms
Tuesday's 8.3-inch snowfall at O'Hare pushes the site's seasonal snow tally to 40.5 inches---well above the 38 inches of snow considered "normal" in a full season. It's the third consecutive Chicago snow season to exceed the normal full-season tally.
Boston and New York missed last weekend's big snow---but not this one
Washington, Baltimore and Philadelphia were all buried by record-breaking snows last weekend which by-passed Boston and New York. That won't happen with the current storm. Heavy snows and howling winds are predicted in both cities Wednesday.
A February snowfall of 10" or more occurs on average only once every 16 years in Chicago. Only five such storms are on the books at Midway Airport in the 81 years since 1929. Tuesday's storm may well become the sixth! Before it finishes with the Chicago area, 8 to 14 inches of snow may accumulate--the season's heaviest to date and the biggest storm to occur here since nearly a foot fell here over two days just over a year ago in late January
The current system's impact on the Chicago area is only in its early stages as Tuesday gets underway. Three rush hours may ultimately be impacted by the system--none more than Tuesday evening's when snowfall will be at its height and winds will be gusting to 25 mph--strong enough to begin sending the additional 4 to 7" of snow predicted to fall Tuesday airborne in some open areas surrounding the city. That's also the period in which an infusion of lake moisture is to begin, supplementing snowfall. Lake enhancement of snowfall could end up spanning 10-14 hours, extending into the opening hours of Wednesday morning even as non-lake-effect snow tapers to passing flurries at inland locations. It's an important reason this storm's heaviest snow totals are predicted to occur in lakeside counties of Illinois, Wisconsin and Indiana.
Explosive intensification of the storm is predicted by computer models later Tuesday as a secondary center forms off the mid-Atlantic Coast. Storms intensify when air rushes aloft at increasing speed. Ground-level winds strengthen as part of this intensification process. The rate at which air ascends increases, encouraging air to rush in from the storm's periphery at faster speeds to replace the upwelling of air at the heart of the storm.
The impact of the current storm's intensification across the Chicago area could become most noteworthy Tuesday night when winds approach their peak, gusting as high as 30 to 40 mph, particularly in areas surrounding the city. Winds of that strength should easily lift snow and hurl it through the air, producing near-blizzard or blizzard conditions. A blizzard is defined by the National Weather Service as three or more hours with winds gusting to or above 35 mph, and during which blowing snow reduces visibilities to a quarter mile or less. The density of structures such as homes and buildings in the city and close-in suburbs often generates enough drag on the moving air to subdue velocities there. But this doesn't happen in open areas surrounding the city, and these areas appear particularly vulnerable to potentially significant blowing and drifting snow Tuesday night.
Latest storm producing 1,300-mile corridor of snow; "Bosnywash" corridor being hit hard again
As unbelievable as it may seem, the Nation's Capital--where a snowfall of 1 to 3" can cause serious travel problems--is under the meteorological gun once again. Just three days from one of the region's worst blizzards in history, forecasters are predicting 10 to 20 inches of new snow may fall as winds strengthen later Tuesday. This promises a rash of new travel problems.
As low pressure moved out to sea Saturday, the mid-Atlantic states of Virginia, Delaware, Maryland, New Jersey and Pennsylvania were digging out of record snowfalls. Totals in the Washington,D.C. area ranged from a low of 17.9 inches at Ronald Reagan National Airport to 40 inches in the northern suburb of Colesville, MD. Dulles Airport reported a record 32.4 inches. Philadelphia measured 28.5 inches with just over two feet in downtown Baltimore. Atlantic City had 18 inches while New York City received just a trace of snow in Central Park. Even locations in western Virginia and Maryland and eastern Pennsylvania had 1 to 2 feet.
Chicago in path of next storm
A storm is forecast to move out of the central plains and merge with a strong upper air disturbance coming in from the northwest Monday. Snow is expected to spread into the Chicago metro area Monday night and increase in intensity Tuesday. At this stage it's still too early to determine the exact track the center of the storm will take, but if preliminary guidance proves correct, northeast Illinois as well as southeastern Wisconsin and northwest Indiana are in for significant snow accumulations. Strong easterly winds would causing considerable blowing and drifting snow making travel extremely dangerous.
The Mid-Atlantic continues in the grip of a crippling snowstorm as Saturday dawns. Snow is predicted to continue falling heavily into early Saturday afternoon amid howling northeast winds from Washington D.C. north to Baltimore, Philadelphia and Atlantic City. Final tallies are likely to exceed 20"--and may well top 30" in mountainous areas of Virginia, Maryland and southern Pennsylvania to the west of the Nation's Capital--more than in the pre-Christmas storm which clobbered the area.
The storm, which on Friday generated snow over a 1,000-mile swath extending from Missouri to the Maryland and New Jersey coasts, threatens to generate record-breaking snowfalls which may challenge some of the region's long-standing winter benchmarks.
More than 10" of snow had fallen in the Nation's Capital late Friday evening, and heavy snow continued falling nearly horizontally there in roaring 32 mph winds--slashing visibilities to near white-out levels. Dulles International Airport, situated outside Washington in northern Virginia, reported 1/16 of a mile visibility in heavy snow late Friday evening while visibilities at Reagan-Washington National Airport were down to a quarter mile. Frostburg in the Maryland mountains reported 15" of snow on the ground late Friday evening with thunder snow in progress, while 17.5" had fallen at Headsville, W.V., in the northeast corner of the state near the Maryland border.
Rapid intensification of the storm is predicted to generate 50-plus mph wind gusts and full blizzard conditions on the coast and in areas close-by including Atlantic City Saturday before the storm finally moves out to sea late in the day.
Storm snowfalls may challenge all time Washington & Baltimore benchmarks for the most snow
In Chicago, the benchmark winter storm was the Blizzard of '67 which crippled the city with a 23" accumulation delivered on roaring 50 mph gusts. But in Washington, the snow-producer of record is the Knickerbocker Storm of Jan. 27-28, 1922. That storm bears the name of the theater which suffered a deadly roof collapse when 28" of snow fell. The collapse killed 98 and injured 133.
Forecasters warned late Friday that the current system could produce accumulations in sections of the Washington area approaching such levels. Predicted totals of more than 20" from this storm in Baltimore could end up challenging the 28.3" record tally recorded there in the President's Day Storm of Feb. 15-18, 2003.
Modest snow Chicago area snow totals Friday
Snowfall Friday in Chicago was far less impressive, reaching an inch at a few mainly south suburban locations in the afternoon. Lansing topped the accumulation list with 1.4" of snow while 1.2" fell at Willowbrook and 1.1" came down at Richton Park. In the city, an inch fell at Midway Airport, but amounts tapered to just 0.2" at O'Hare. West suburban Oak Brook and Downers Grove saw just 0.5".
Sporadic lake-effect flurries are to ride gusty north to northeast winds into sections of the metro area Saturday, but any accumulations are expected to be modest.
Monday night/Tuesday system bears some resemblance to Jan. 7-8's snowstorm here
A significant Chicago snowfall remains a risk Monday night and Tuesday. Much can change in two days--but computer models late Friday continued to indicate a southeast-bound speed max in the jet stream is to sweep from the Dakotas later this weekend into central Illinois Tuesday--potentially placing Chicago in an area of strong atmospheric "lift" Monday night into Tuesday. That's a set-up notorious for snow production.
The latest storm in what already has been an incredibly active winter season out East is headed for the major cities of the Mid Atlantic--including Washington, Baltimore, Philadelphia and possibly at least sections of the New York metropolitan area later Friday--while threatening Chicago with a period of snow and a weekend of chilly, lake-driven snow showers. The mammoth system is only to graze the Chicago area--reserving its fiercest blow for the mid-Atlantic where blizzard conditions are likely to evolve, driven by 40 mph gusts. Coastal areas such as Atlantic City, may well see white-out conditions brought on by winds as high as 50+ mph.
While a bit of drizzle or freezing drizzle possibly mixed with some ice pellets or a few flakes of snow flirt with Chicago Friday morning, a steadier period of snow is slated to arrive here later this afternoon and Friday night. An inch or more of snow has fallen on only 3 calendar days since Jan. 1. The incoming snow could lay down 1-3 inches of snow over sections of the Chicago area, becomingthe 4th one-inch-plus snow event of 2010.
Snow is predicted to be falling vigorously by mid and late afternoon Friday in Washington D.C. That city already has a 2009-10 seasonal snow tally of 31.1 inches-- three times the normal of 12.4 inches to date. Remarkably, only 2 inches had fallen there by this time a year ago. The current season's snowfall---even in advance of the incoming storm---amounts to more than ALL the snow recorded across the District in the last 3 seasons combined.
As much as 16 to 24 inches of snow is predicted to fall there in the latest storm amid howling winds---and a foot or more of snow appears a good bet in Baltimore and Philadelphia as well. Effects of the storm are likely to be felt in those cities well into Saturday---though the heaviest falling snow is to begin winding down midday tomorrow.
Gusty, cold weekend winds to activate the lake snow machine
The storm's impact on Chicago's weather is expected to be far less radical. But the process of intensification---known as "cyclogenesis"--- will encourage air to rush into the system from its periphery, a set-up which is to manifest itself in the strengthening east to northeast winds likely to race through Chicago Friday. Gusts to 30 mph are possible by and during Friday night.
Lake-effect snow showers hit Saturday/Saturday night
Winds will blow from a northeast direction Friday night into morning then become more northerly. It's a change which will increase the distance cold air travels over lake waters before reaching Chicago Saturday, raising the possibility initially light and scattered bursts of lake-effect flurries in the morning may increase to better-organized snow showers later in the day into Saturday afternoon and night.
Potent system bearing some similarities to the early January snow-maker here being monitored next week
A second, potentially more significant snow-maker may threaten the Chicago area area Monday night into Tuesday. The southeast-bound disturbance, predicted to dive from Manitoba Canada into Missouri Monday then track across Illinois. It's a development which could put Chicago in a strong region of "atmospheric lift" Tuesday setting the stage for snow.
If all the atmospheric chips fall into place in just the right way over the next week, the Chicago metro area could rack up snow tallies larger than the 4.5 inches of snow which fell all of last February. But the onset of snow isn't likely to occur until Friday--comparatively mild air is in the cards first. Thursday afternoon may host Chicago's mildest official high of the past 11 days.
Readings Wednesday hit 33-degrees at Midway Airport, 35 at the lakefront and 32 at O'Hare. The 36-degree official reading predicted for O'Hare Thursday afternoon would be the area's mildest since a 46-degree high on Jan. 24--nearly two weeks ago.
All is far from sanguine in the world of U.S. weather. A major storm is again under development--this time in the southern Plains. It's the first of two expected to come together in the next 7 days. The latest system has prompted the issuance of an array of winter storm watches and advisories across sections of 23 states--extending from New Mexico and the Texas Panhandle all the way to the East Coast near Washington, D.C. The developing system is behind a series of gully-washing (and thundery) downpours which drenched south Texas Wednesday. Fredericksburg --northwest of San Antonio--measured 2.64 inches of rain while San Antonio proper logged a 2.50 inches daytime tally. Big snows on the storm's cold northwest side buried the mountains of New Mexico near Albuquerque with as much 8 inches of snow.
The storm is to move from Gulf Coast waters east of Texas northeastward toward the South Carolina coast. It arrives there Friday afternoon then explosively deepens once in contact with western Atlantic waters east of North Carolina. It's at that point snowfall and winds should begin increasing rapidly across sections of the mid-Atlantic---including Washington, Baltimore and Philadelphia.
With the 2009-10 snow tally in Washington, D.C. now up to 31.1 inches---nearly 16 times the 2 inches which had fallen by this time a year ago and more than ALL the snow which has fallen there the past three seasons combined--another major winter storm is not what East Coast residents need. The books closed on the region's last storm only earlier this week.
Providing the storm remains on the track now projected for it, a foot of snow could fall on the Nation's Capitol by Saturday. The strong winds on its north side are likely to buffet Chicago as well, strengthening slowly Friday and gusting to 30 mph at times Friday night and Saturday.
Estimates of how much snow the southern storm may produce here between Friday afternoon and Saturday night range on various computer models from 2 to as much as 5 inches--with possible lake-enhancement. These are preliminary figures which will be updated. Precipitation here may begin late Thursday night as a bit of drizzle, freezing drizzle, sleet or flurries likely to increase in intensity Friday afternoon and evening.
Rare mid-winter Air Pollution Action Day declared by Illinois EPA
It's not often an Air Pollution Action Day is declared in winter--but it happened Wednesday and extends through Thursday. A pollutant-trapping temperature inversion above Chicago, which in combination with light winds, has shut down the mixing of air which typically thins pollution concentrations, continues in place. Stronger winds will begin taking hold as the latest storms passes to the south bringing the pollution episode to an end.
It's been nearly a month since the Chicago area has been blanketed by a fresh layer of snow as heavy as Tuesday's. The 1.7 inches which fell at O'Hare was the heaviest since an early January snowstorm buried the metro area under 7.4 inches of snow--the season's heaviest to date. Though snow accumulated from one corner of the Chicago area to another, its was the west and north suburbs which registered the heaviest totals. Accumulations of 2.5 inches hit Arlington Heights and St. Charles while Oak Brook and Lake Bluff registered 2.1 inches. The snow fell in a quiet wind environment and with temperatures which hovered near or just above freezing at many locations. This spared motorists on the area's major thoroughfares serious travels problems since road chemicals were able to work at maximum efficiency. Seasonal snow tallies surged to 31.9 inches Tuesday---well above the average of 22.4 inches to date--but just over a foot (12.1 inches) behind the same period a year ago.
Some sunshine breaks from the clouds Wednesday--and a southerly wind Thursday is likely to push temperatures above freezing for the first time in 11 days. But, the break in snowfall may be temporary. At least two systems capable of new snowfall loom in the coming week and are being monitored. The first is due Friday afternoon and evening and may, with the arrival of lake effect snows late Friday night and Saturday, extend into the first half of the weekend. Early computer estimates suggest significant accumulations are a good bet. Models run by the U.S. Navy and Environmental Canada put possible snowfall at 3 to 5 inches. Moderately colder air follows the windy disturbance into the area Saturday night and Sunday.
A possibly more potent system sweeps southeastward from Canada on Monday into Tuesday. Even colder arctic air may follow.
A winter like none recently in the Nation's Capital; District hit by new snow and another due late week
Washington, D.C., has already received more than 2 feet of snow this winter and another snowstorm is possible there this weekend. In stark contrast, at this point last winter, snowfall there totaled only 1.9 inches.
Snow--modest by February standards---greets poll-bound area residents Tuesday. It's the first to fall in February and marks the 20th day this season measurable snowfall has occurred . It comes only days after the close of a January which tallied just 9.1 inches of snow, more than 80 percent of which (7.4 inches) which fell in a single early month storm on Jan. 7-8. The month's snow tally was 11.3 inches below the most recent thirty year average and more than a foot (12.4 inches) below January a year ago.
Tuesday's slushy Election Day accumulations are likely to range from 1 to a little over 2 inches--most of it accumulating on untreated outdoor surfaces, such a side streets, sidewalks and driveways. Absent Tuesday will be significant wind and bitterly cold arctic air, regular visitors in early February. Only 14 years ago in 1996, the city shivered through a bitter three-day cold spell during which a majority of hourly temperatures remained below zero setting new records--not only for the coldest Feb. 2 and 3 overnight lows on the books since 1871, but for the coldest daytime high temperatures as well.
Coming days will be nowhere near as cold Daytime highs reach the 30s Tuesday and Wednesday and may make a move on 40-degrees away from Lake Michigan Thursday. These are temperature levels which assure road chemicals will work at maximum efficiency.
The sections of the metro area which receive 2 inch tallies Tuesday will have received nearly half the total amount recorded here ALL of February 2009. The month logged measurable snowfall on only four days.
Snows end as sunshine emerges Wednesday. But a second system approaches Thursday bringing clouds back into the area even as southeast winds tap milder air and push readings in the sections of the Chicago area away from Lake Michigan to near 40-degrees. However, the warming will be short-lived. Winds between a strong Canadian high pressure to the north and a developing storm to the south will increase Thursday and Friday. The gusty flow it is expected to tap the reservoir of arctic air covering much of Canada and the far northern tier of the U.S., tugging the frigid air southward into the nation's Heartland over the weekend and into early next week.
Miami area hit with Monday downpours; totals top 8 inches in spots
As the clean-up continued Monday in the wake of gargantuan weekend snows from New Mexico to Virginia and the Carolinas, thunderstorms drenched south Florida Monday, hitting an area from Ft. Lauderdale and Hollywood to Miami and Homestead especially hard. Flood warnings were hoisted after 8.13 inches drenched Cooper City, 7.61 inches Pembroke Pines and 7.38 inches at Ft. Lauderdale. The rains flooded area thoroughfares.
