Winter 2009-10 opened with a snowy flourish with more than 28 inches falling in December and early January, but since then, only meager snow amounts have been recorded as the area's snow cover has dwindled to an inch or less.
Despite the recent lack of snowfall here, major snowstorms have buried the South and current national snow cover stands at 70 percent, the highest value recorded since observations began back in September 2003.
While no major snowstorms appear in the offing for Chicago, two systems have the potential to deliver accumulating snow. The first on Monday night and Tuesday should be a minor event bringing an inch or two with heavier totals expected north and west of the city. The second one, slated to arrive Friday night, could start out as rain but change to accumulating snow as colder air returns on Saturday.
Extreme cold lacking
With two-thirds of meteorological winter behind us, the city has officially recorded only one day with below zero readings: a low of minus one on Jan. 3. By this time last winter the city had recorded nine subzero days, including a low of 18 below zero on Jan. 16.
Cold weather continues to grip the Chicago area this weekend, but aside from a dusting of lake-effect snow in the city and northern suburbs Friday night and early Saturday, dry weather was the rule. In sharp contrast, the South is reeling from another major winter storm that left a three-day, 1500-mile-long legacy of snow and ice from Kansas and Oklahoma all the way to the Atlantic coastal areas of Virginia and the Carolinas. More than a foot of snow fell in many areas including 13 inches at Lynchburg and Forest, both in Virginia, and 13 inches at Mills River, N.C. South of the snow, a heavy glaze caused extensive damage to trees and power lines and created an icy havoc on roads. This is the second major storm of the winter to blast these areas, the first occurring in the days leading up to Christmas.
Snowy primary day shaping up
The next weather system is likely to spread its wintry precipitation farther north, bringing some snow to the Chicago area Monday evening and continuing into Tuesday, the day of the Illinois primary. While a major snowfall does not appear to be in the offing, it does appear that at least a couple of inches of snow could accumulate here by Tuesday afternoon.
January moves into its final two days this weekend, closing as it opened--COLD! The bitterly cold readings are easing slowly with time. Daytime high temperatures warmed from 13 to 21 degrees Thursday to Friday, and even higher readings are on tap Saturday and Sunday. But while the mid to upper 20s predicted both days continue the recent temperature upswing, they will fall nearly 20 degrees shy of last weekend's unseasonable mid-40s.
Flurries continue fluttering earthward as Saturday gets underway. A modest lake-effect snow event is in place--but the depth of the day's cloud layer is shallow compared to those which have produced more prolific and heavier snows in the past. Barring the unexpected, accumulations appear likely to remain limited, both in depth and areal coverage. Winds are to become even less supportive of lake snow development as the day proceeds, allowing precipitation to taper to sporadic flurries this afternoon and evening.
Longer days, strengthening sunlight hits milder temperatures ahead
It takes a while to transition from one season's temperature regime to the next. But the astronomical groundwork for the move to spring is falling into place. Days are lengthening and the strength of sunlight is on the rise. Chicagoans can look forward to an additional hour and 15 minutes of daylight in the next 30 days--and to two hours and 45 additional minutes of sun two months from today. Though it may seem an eternity to the winter weary here, Chicago weather records reveal the average final 32-degree temperature occurs on or about April 19th at Midway Airport and April 26 at O'Hare Airport. And the majority of daytime highs reach or exceed 70 degrees in Chicago 50 percent or more of the time beyond May 23.
Winter woes from Mid-Atlantic westward into the Midwest
While chilly here, Chicago's weather problems pale in comparison to those of recent days along a 2,000-mile swath extending from New Mexico and Oklahoma east to the Carolinas and Virginia. There, heavy wind-driven snow accumulated to a depth of as much as 14" in spots. Snowfall Friday piled up quickly in North Carolina, reaching 9" at Asheville by nightfall. Storm tallies since Thursday include 14" at Gruver, Texas; 10" Enid, Okla.; 11" Ingalls, Kan., and 8" Henderson, Tenn.
Snow could fly Monday night and Election Day (Tuesday)
An eastbound disturbance off the Pacific may be the next to deliver snow to the Chicago area. The period in question is Monday night into Primary Day (Tuesday). Temperature changes at high altitudes offer forecasters clues on the potential extent/intensity of snowfall a weather system may produce. Projections from computer models in the Monday through Tuesday time frame is hinting at fairly impressive warming at high levels of the atmosphere (around 40,000 feet). It's a development which suggests air within the system is likely to be rising vigorously enough to support sticking snow. The system will be monitored in coming days as it proceeds toward the Midwest.
A modest lake-effect snow set-up appears to be trying to come together for Chicago and the lakeside counties of southeast Wisconsin, northeast Illinois and northwest Indiana in the next two days. Friday is to dawn with sunshine on display in the city and over much of the metro area---sun which is to begin mixing with clouds in lakeside areas as the day proceeds. Flurries may follow later in the day and from time to time over an approximately 28 hour period extending into Saturday night.
Lake effect snow flurries have been fluttering to earth across the western Michigan snow belt southward into north-central Indiana since Thursday. A change in wind direction, dictated in part by the influence of a powerful storm system passing well to Chicago's south and lambasting the Plains with ice and snow, may encourage those flurries to begin building westward in the hours to come. Frigid northwest winds driving snowflake development in Indiana and Michigan are predicted to back slowly Friday---first to the north and then to the northeast. The effect will be for lake clouds blowing Friday morning into sections of the Indiana and Michigan snow belt to gradually shift west---ultimately moving them closer to Chicago. Predicted wind profiles suggest the first lake-effect flurries could reach the western shore of Lake Michigan---including the city---as early as mid afternoon to early evening.
A wind speed increase is to follow just above the ground Friday night into Saturday. It's at this point flurries may build at times into some heavier snow showers. That would happen as faster- moving air coming off the lake converges with winds slowed by the frictional drag encouraged as they contact land. A pileup of air results when faster winds converge with slower-moving air and upward motion soon follows. That cools the air to condensation increasing cloud development, at the same time allowing snowfall intensity to increase. As with all lake-effect snow situations, it's unlikely to snow continuously. Snow is most likely to fall in distinct spells. But, some accumulation may occur if the situation unfolds as predicted.
75 percent of Chicago's winters have produced a colder temperature by now
Weather records reveal 107 of the 139 winters on record here since 1871 have produced a colder temperatures by this date than the 1-below which stands as THIS season's coldest. Thursday's high of 17-degrees occurred at midnight---a peak reading of 13-degrees occurred during daylight hours. It was the coldest air to engulf the city in the 26 days since Jan. 2. Winds chills---other than the readings taken at midnight---failed to break above 0-degrees---falling as low as 11-below around 7 a.m.
Oklahomans jarred by temp plunge; spring warmth replaced by ice, wind and snow
A nightmarish scene unfolded Thursday across sections of the southern Plains. The region had basked in spring like 60s only the day before. But the same arctic air mass behind Chicago's frigid temperature regime dove into Oklahoma and north Texas, sending temperatures plunging as sleet, freezing rain and wind-driven snow hit the area. Temperatures Thursday afternoon in Oklahoma City dipped into the 20s amid howling northeast winds amid heavy sleet and freezing rain. Readings 24 hours earlier had topped out at 65-degrees.
The inch and a half of ice which built-up on many outdoor surfaces in Oklahoma brought trees and power lines down across the region inducing widespread power outages. Among the areas hardest was Jackson County, southwest of Oklahoma City, were at least 200 power poles snapped.
It was heavy snow which was big news in the Texas Panhandle, northern Oklahoma and southern Kansas. Top accumulations had reached 13 inches by nightfall Thursday.
Arctic air tightens its grip across the Midwest Thursday. A highly-reflective fresh cover of snow all but assures sub-zero wind chills will dominate the day despite the presence of sunshine.
Sunlight typically heats air indirectly, warming the ground onto which it falls first. A fresh accumulation of snow defeats that process by reflecting solar energy back to space. Wednesday afternoon and evening snowfalls included 1 inch in Plainfield and Yorkville as well as at Schererville and Highland in northern Indiana. Other Wednesday snow totals included 0.9 inches at O'Hare, 0.8 at Peotone. 0.6 at Oak Brook and 1.2 inches in Portage Ind.
Computer trajectory forecasts, which track the movement of air indicate Thursday's chill originated in the Dakotas 24 hours ago. There, temperatures flirted with zero Wednesday. With news snow in place, it's likely the air mass will retain its arctic character as it arrives in Chicago allowing temperatures here to rise no higher than the teens and to drop sub-zero away from the lake Thursday night. Gusty northwest winds of 10-22 mph Thursday assure wind chills will remain between 0 and 12 below.
Arctic air deflecting major snow and ice storm south of Chicago
The blast of arctic air is having a major impact on the track of the latest Pacific storm to come ashore in the United States. The system emerges from the southern Rockies into the southern Plains Thursday and proceeds east assuring its formidable snows and accumulations of ice remain well south of Chicago. In Oklahoma, where residents basked in springlike 60s Wednesday, plunging temperatures and howling east winds are to deliver ice and snow Thursday. The storm's impact may not completely bypass Chicago. Its winds are to interact with a Canadian high pressure producing a north-to-northeast flow which begins sweeping into Chicago off Lake Michigan late Friday through Saturday. Over that 28 hour period the potential for lake-effect snow showers and flurries rises here. Some accumulation is not out of the question.
El Nino taking a big bite out of seasonal snow tallies here
Each El Nino has its own character. The differences from one such period to the next can be formidable. But, as a general proposition, El Ninos are known to produce storms which crash into the West Coast---last week's storm parade serving as a spectacular example---then tracking through the southern states. It's a development which boosts cold season snowfall in the Plains but often slashes snowfall in the Midwest. Data from these regions on snowfall to date indicates how closely this season's snowfall is tracking with many past El Ninos. Snowfall is substantially lower in Chicago and the area which surrounds it this year versus last. O'Hare's snowfall (prior to Wednesday's system) is more than 13 inches lower than a year. Other declines include Rockford: down 23.7 inches from a year ago, Milwaukee off 27.5-inches and South Bend with a seasonal tally down 23.2 inches.
Blizzard conditions, the product of 50+ mph winds which sent 4 to 6 inch snow accumulations airborne across Iowa late Monday, slashed visibilities to zero and brought travel to a standstill. In some areas, officials ordered snow plows off highways because of multi-car pile-ups. I-35 north of Des Moines and a section of I-90, from Albert Lea west to the South Dakota border, were closed.
The cold air's return marked the end of a two week break in frigid arctic air which had dominated so much of early and mid January. The latest frigid blast follows on the heels of 44 and 46-degree highs Saturday and Sunday---the mildest temperatures here in the nearly 2 months since early December. The recent mild interlude nudged Chicago's meteorological winter temperatures (the readings logged since Dec. 1) to more than 5-degrees ahead of a comparable period a year ago.
Bursts of snow accompanied the cold air's arrival here producing accumulations of 1.1 inches at south suburban Beecher and Peotone, 1 inch Schneider, Indiana, 0.6 inches Downers Grove and 0.4 in Oak Brook.
Disturbance to bring flurries Wednesday; lake snow threat grows with an even colder push late week
Peeks of sun may emerge at times from flurrying clouds by Tuesday afternoon. But a frontal system's arrival Wednesday re-establishes an overcast and ignites a new round of flurries. What follows Thursday and Friday is still colder air which is likely to push nighttime readings near or below 0-degrees outside the city Thursday and Friday night.
Storm projected at present to track to the south, a forecast which will be monitored
That surge of colder arctic air later this week has driven the predicted track of a storm landfalling on the West Coast Tuesday farther south. If that projection holds up, it would keep the system's biggest snows well to the south of the Chicago area. But, track forecasts will be monitored. Any northward jog in the system's path would bring its snow farther north too.
What seems even more plausible at the moment is the possibility the storm's circulation in combination with a cold Canadian high to the north may encourage snow showers to blow off Lake Michigan into Indiana's snowbelt Thursday---and possibly into Chicago and the Illinois shoreline late Thursday night and Friday.
Anniversary of Chicago's worst snowstorm: The Great Blizzard of 1967
It was 5:02 a.m. in the morning on this date 43 years ago that a snowstorm destined to become the Chicago area's worst on record got underway. By the time its blizzard-like snowfall ebbed, the city had been buried beneath 23.0 inches of snow. The infamous Blizzard of '67 brought the city to a standstill, stranding 50,000 cars and 800 CTA buses in drifts on the city's thoroughfares. Only two days before, on Jan. 24, area residents had enjoyed a record-breaking 65-degree high.
Low pressure and the associated cold front will move east through Chicago Sunday morning. Overnight rains will continue this morning before diminishing behind the cold front this afternoon. The combination of 40-degree-plus temperatures and dewpoints, strong winds and up to an inch of rain should be enough to pretty well eliminate any snow cover over northeast Illinois. Much of this rain and water from snowmelt will run off, causing pooling in low-lying, poorly-drained areas, as well as rises on rivers and streams, many of which are already near bank full.
Cold air and snow follow
As temperatures fall into the 20s, wrap-around snow behind the departing low pressure system will hit early Monday and continue into Tuesday. With blustery northwest winds gusting to 30 mph, there will be considerable blowing, but a thin inch or so coating of snow could accumulate. Cold air will hold the remainder of the week, with a possibility of an accumulating snow reaching into northern Illinois Thursday.
Ice/snow further north
Freezing rain, 40 to 50 mph winds and heavy snow hit North Dakota and northern Minnesota Saturday downing power lines and creating near blizzard conditions. Additional snow will continue over these areas through Sunday.
Waves of heavy rain hit late Saturday into Sunday morning and are likely to spell doom for what remains of the city's snow pack. An inch or more of snow has covered the ground at Midway Airport the past 28 days. The snowpack has managed to survive since just after Christmas even with arctic air a no-show the past 11 days.
A wet storm, likely to unleash an inch or more of wind-driven rain across much of the Chicago area as darkness settles in Saturday evening, spins up on the nose of the same powerful jet-stream-level wind max which has hammered the West with a week-long parade of vicious Pacific storms. The storm headed for Chicago develops over Arkansas Saturday, then lifts north into northern Illinois Sunday morning. Mild air is to rush into the area with the system -- but will be masked for a time in lakeshore areas by strengthening southeast winds slicing off chilly 33-degree lake waters. Rising temperatures and humidities are likely to speed the snow cover's demise Saturday night. A combination of the snowmelt and heavy downpours is likely to produce tremendous run-off, making standing water a good bet into Sunday.
The absence of snow isn't likely to last long here. A realignment of atmospheric steering winds is to reinvigorate arctic air, chased into North America's northernmost reaches the past two weeks. The chill is to crash southward over most of eastern North America over the next week. Slow cooling commences Sunday afternoon when temperatures are to back off low and mid 40-degree morning highs, settling into the mid-30s by nightfall. The cooling accelerates amid snow showers Monday when highs may fail to break out of the 20s. By Tuesday and Wednesday, frigid air will be back in full control with highs struggling to reach 20 Tuesday and the low 20s Thursday.
What happens next (mid and late week) will have to be monitored. Computer models suggest a potentially significant eastbound snow system could emerge from the Rockies midweek and swing into at least portions of the Midwest Thursday. The system has the potential of producing accumulating snow.
Parade of El Nino storms finally breaks out West
California residents, at the mercy all week of El Nino-enhanced storminess, have seen flooding rains and mudslides, hail with unusually energetic thunderstorms, a series of small but damaging tornadoes, and travel-inhibiting snows in the mountains. Los Gatos, south of San Francisco, topped late Friday rainfall tallies for the week registering 16.30". Snowfall reached 90" (7.5 feet) at Mammoth Lakes, Calif. -- more snow that Chicago logged in its snowiest winter on record (89.7" in 1978-79). The big snows weren't limited to California. Flagstaff, Ariz., has been buried beneath 53.5" of snow, and heavy snows have occurred in the mountains of Utah, Colorado and New Mexico. Precipitation winds down across the region this weekend.
Los Angeles and Las Vegas are hardly areas which come to mind as meccas of record-breaking low pressure any more than Phoenix, Arizona is known for regular tornado touchdowns. These are exceedingly rare events in southern California and the deserts of the Southwest--- yet with the atmosphere over the region contorted into an abnormally stormy state by a jet stream bearing winds as high as 260 mph over the Pacific in recent days---velocities all but off-the-charts even at 30,000 ft.---these events were just a few of the weather anomalies which have plagued the West. A battery of four storms which have hit one after another have initiated California mudslides, played havoc with air traffic and buried Golden State mountaintops under 6 or more feet of snow. Gargantuan snowfalls haven't been limited to California's mountains. Measurements at the Grand Canyon in Arizona put Thursday's snow cover at 50 inches---more than 4 feet---and Flagstaff, in the northern section of the state, has been hit by more than 3 feet of snow since the El Nino-influenced storms began arriving.
Rare tornadoes touch down
What may have been a brief tornado touch down in a Phoenix area shopping center 6 miles west of Scottsdale Thursday, is only the latest report of a twister to dip from the West's turbulent skies this week. A Weather Service survey team dispatched out of the Oxnard, California forecast office to check into reports a tornado had touched down in nearby Ventura, hurling a car into trees there, confirmed the touch down. The EF0 intensity twister, bearing 65-86 mph winds, churned along a path a mile and a half long.
Thursday's weather played havoc with air traffic in the southwest. Flights were suspended much of Thursday at Burbank, Ontario and San Diego airports in California as well as at Tucson and Phoenix in Arizona. Winds---even outside of the day's frequent downpour-generating thunderstorms---often gusted above 60 miles per hour.
Rainfall in the hardest hit foothills around Los Angeles grew to more than 14 inches late Thursday while peak wind gusts in recent days have topped 106 mph at higher elevations in the Sierra.
The storm which slammed into California Thursday was the fourth in less than a week. It heads for the nation's Heartland and likely to bring Chicago strengthening winds over the weekend and Saturday sprinkles which build into possibly heavy rains at night. The system may deposit as much as 0.50 to 1.25 inches---much of it expected Saturday night into Sunday morning.
Chicago's winter among 25 percent coldest--but running milder and less snowy than last winter
The dramatic pullback of cold arctic air in the past 11 days hasn't erased the temperature deficit Winter 2009-10 is running to date. Despite overall temperatures at levels 2.8-degrees below the 140-year average since Dec. 1, El Nino has appears to have had some impact. The period is averaging an impressive 4.1-degrees milder the comparable period a year ago and has produced 13.3 fewer inches of snow.
Thundery 6-7-inch rains sweep north Florida
The West isn't the only region which has been hit with big rains. Thunderstorms, which towered to heights of 47,000 ft. and swept north Florida and the Southeast Thursday, generated 6 to 7 inches of rainfall in north Florida.
Iowa and sections of central Illinois bore the brunt of an ice-storm which only lightly glazed sections of the Chicago area Wednesday and Wednesday evening. Weather spotters across the south and west suburbs reported the heaviest accumulations of ice, including 0.2 inches at Portage, Indiana and 0.1 inch near Kankakee, Peotone, Pontiac and the northwest suburban town of Winnebago in Winnebago County. Precipitation began south of Chicago mid-afternoon and had worked into the city as the evening rush hour got underway. With temperatures hovering at or just below freezing, road chemicals were able to work at maximum efficiency and there were few problems reported on metro area thoroughfares. The scene was a very different one farther west. Icy morning roads led to the closing of schools in west central Illinois' Macomb. Freezing rain proved even more formidable across Iowa and into eastern Nebraska and sections of southern Minnesota. Hardest hit was the area west of Des Moines where as much as 0.8 inches of ice coated the landscape taking down large 10 to 12 inch diameter tree limbs in strong 30+ mph wind gusts. Power was knocked out to thousands of Iowa homes.
The system behind the wind and ice across the Midwest was the first to ride the rare 240+ mph jet stream into the West Coast just three days ago. Sprawling Pacific storms which lambaste California and the West Coast are common features of El Nino cold seasons. This season's storms have been late in arriving. It's not uncommon for El Nino storm barrages to get underway in December.
The stronger than usual "SUB-TROPICAL" (southern) jet streams fostered by El Ninos lead to many of the events' most common winter weather abnormalities across the Lower 48 states, among them wetter than normal weather across the desert Southwest and active severe weather outbreaks across the Deep South. Both were in evidence Wednesday. Waves of downpour-generating thunderstorms produced 16 reports of tornadoes across sections of Texas and Louisiana.
California continues taking meteorological beating from El Nino-powered storms
The meteorological assault on California continued Wednesday. Electricity to 27,000 Sacramento area customers was out as a rare barrage of winter thunderstorms produced power line-downing wind gusts as high as 60 mph. Winds hit 59 mph at San Francisco and 61 mph at Elk Grove, just southeast of Sacramento. Even stronger winds have been clocked in recent days. Velocities as high as 104 mph whipped the crest of the state's Sierra range at Ward Mountain.
An automated Snotel sensor at Chagoopa Plateau reported snowfall since the parade of storms began late this past weekend had reach 73.6 inches---more than 6 feet---Wednesday. Snow and ice forced the closure of I-5 at the 4,100 ft. level of Tejon Pass east of Los Angeles. And two Southwest Airlines jets were struck by rare lightning Wednesday at the arrival gate of Burbank's Bob Hope Airport Wednesday.
Monterey California typically see three thunderstorms in an entire year---but six have swept the city in just the past three days.
Colder pattern threatens return of sticking snow beyond weekend
Computer models indicate sticking snow may return to the Chicago area over the coming two weeks. The twelve most recent runs of the National Weather Service's Global Forecast System model have generated total 2 week snowfall estimates averaging 6 inches.
Winter storm watches have been hoisted for the northern Plains beginning Friday night, continuing through much of the weekend. A foot or more of snow may occur there as another of the El Nino strengthened storms jumps the Rockies and spins into a formidable winter system likely to rain on Chicago---but expected to snow across the Dakotas and northern Minnesota.
Chicagoans have learned through hard experience winters here can be vicious. But a cold blast of the intensity of the one which hit 25 years ago remains in a league all its own. To this day it is the coldest spell of weather ever to grip the city. Temperatures that brutal 1985 morning plunged to 27-degrees-below zero amid 15 to 30 mph winds which generated a 77-below wind chill. (The wind chill index has since been revised and the same combination of wind and temperature would result in a still almost unimaginable 57-below wind chill today).
Never before Jan. 20, 1985 had a morning been so cold. Trees and buildings crackled in the bitter arctic air and movement in the city slowed to a crawl as cars and other vehicles failed to start in a level of chill which physically hurt.
That a 27-below reading was even possible here was surprising to many. Chicago's official temperature records date back to 1871--and there had NEVER been a reading as cold before. The mid and late 1970s produced a series of intensely frigid cold seasons and one---the 1978-79 season---delivered snow with such frequency, it was widely credited with producing a January blizzard which sent Mayor Bilandic packing, allowing Jane Bryne to move into City Hall. The season ended up the snowiest here ever with a total of 89.7 inches to its credit by the time it closed.
Collectively, the winters of the 1970s were the worst of any in more than a century of weather records. Then came Jan. 10, 1982 and the mercury slipped to the city's new all time low: -26-degrees with 40 mph wind gusts which pushed wind chills to an unimaginable 90-below. It was, area residents were told at the time, a once in 300 year event climatological event. Only a week later, readings slipped to -25-degrees, challenging the assertion. But it was this date in 1985 which ended up producing Chicago coldest temperature ever: -27-degrees.
Wednesday dawns nearly 50-degrees warmer. The first in the series of stormy weather systems which have crashed onto the West Coast in recent days onboard a 200 mph jet stream, is bearing down on the Midwest and threatening freezing rain and ice. Ice storm warnings cover a good chunk of Iowa Wednesday into Thursday and freezing rain advisories have been hoisted in central and western Illinois.
Chicago's thickening Wednesday overcast precedes the disturbance and will hide the sun in time, bringing the area some freezing rain Wednesday night and Thursday. The system is to produce this area's strongest winds in a week. A more impressive storm follows this weekend and could douse the area with rains which begin in light, scattered patches Saturday and crescendo into heavier downpours Saturday night.
There are growing indications cold air regains its control of Midwest weather next week. Scattered rain Sunday may switch to snow or snow showers Sunday night into Tuesday---and recent longer range computer projections into the 1 to 2-week time span suggest sticking snow is to become increasingly likely in the Chicago area and over a wide swath of the Midwest.
California blasted by powerhouse El Nino-enhanced storms; twisters, thundery downpours, 90+ mph gusts and huge mountain snows result
Tornadoes and severe thunderstorms swept ashore within the latest in a string of powerful Pacific storms Wednesday. Additional storms are expected to continue slamming into the West Coast the remainder of the week. California is at the epicenter of the meteorological assault. Three twisters were reported in the Los Angeles area Tuesday, including one which touched down at Huntington Beach, tossing boats 20 to 30 feet into the air and flipping a limo and SUV. Lifeguards at nearby Newport Beach clocked 93 mph thunderstorm gusts. Winds reached 100 m.p.h. and rains approached 5 feet in the region's mountains and foothills. A 64 mph gust swept San Francisco's famed Golden Gate Bridge while 75 mph gusts occurred just north of the central California metropolis. Snowfall near Lake Tahoe approached three feet.
A phenomenal jet stream, boasting peak winds of 246 mph and strengthened by a huge north-to-south temperature spread between -60-degree Siberian temperatures to the north and El Nino-warmed air and water extending from western South America westward nearly the length of the equatorial Pacific, is powering the storm eruption. 200+ mph winds extended late Tuesday more the 4,000 miles from the Baja California coast to the ocean waters east of Japan.
The area's been mired beneath clouds most of the past 5 days. Sun-blocking clouds have been trapped in place by an atmospheric setup referred to by meteorologists as a "temperature inversion." Inversions occur when temperatures warm with height rather than cool as is typically the case. An INVERSION---as its name implies---is a "reversal" in the normal temperature distribution with height. When that occurs, any attempt of moist air in the lowest reaches of the atmosphere to rise and mix with drier, cloud-dissipating air is impeded. In the absence of winds carrying drier air into the area, any clouds already in place frequently survive. That's what's been happening here in recent days.
Chilly air, saturated with moisture from melting snow over the past week and only about 2,400 feet deep, has supported widespread cloudiness. At times in recent days, the cloud deck has been so shallow that the tops of the city skyline has been visible to pilots and airline passengers flying into the area---even as street-level observers have looked up to see the tops of buildings shrouded in clouds.
One result of the persistent cloud cover has been to block the sun. Chicagoans have seen just 17 percent of the area's possible sunshine over the past 5 days--an amount well below normal. Another impact has been the proliferation of tiny super-cooled water droplets in the haze and fog so often a part of the local weather scene of late. Water is said to be "super-cooled" when it remains in liquid form even when its temperature is below freezing. Super-cooled droplets quickly freeze into a layer of ice or ice crystals upon contact with any cold outdoor surface. That process is behind the spectacular hoar frost displays of recent days---the eye-catching layer of ice crystals which have covered trees, shrubs, fences, picnic tables, sheds, barns, and virtually every imaginable outdoor surface.
Some drying of the lower atmosphere Tuesday may permit clouds to thin out and at least some sunshine to emerge. Light winds are predicted and may be a drawback to any clearing. Clouds can be slow to dissipate when light winds are present.
First of El Nino storms on West Coast unleashes 1-4 inches of rains, gusts to 80 mph
Clues of Chicago's weather pattern later this week are evident on the West Coast and desert Southwest. The first in what promises to be a week-long wave of powerful Pacific storms embedded within an extraordinarily strong 230+ mph jet stream hammered California Monday. Severe thunderstorms there unleashed 80 mph wind gusts at a few locations while slopes, denuded by summer wildfires, grew waterlogged, threatening mudslides. Though conditions eased late Monday, additional waves of storminess are on the way. By the time the week ends, 20+ inches of rain threatens to fall on the hardest-hit westward facing mountain slopes while snows at higher elevations may be measured in yards rather than feet.
The first of a series of disturbance expected to jump the mountains and reform to the lee (east) of the Colorado Rockies Tuesday threatens to churn eastward into Missouri and Illinois by Thursday. A huge pressure variation between that system and a strong, chilly Canadian high to the north is predicted to produce strengthening winds in Chicago Thursday. The flow threatens to tug cold air in at lower atmospheric levels as moisture-rich air rides up and over. It's a setup which may lead to freezing rain or a mix of freezing rain and sleet Thursday which would trend to all rain by Friday.
A stronger system is due with additional rain here Saturday into Sunday. The cold air that system may drag into the Lower 48 on its back side Sunday night into next week could bring snow to the Chicago area later Sunday night and Monday.
Chicagoans experienced a cloudy chilly damp day Saturday. High temperatures were 10 degrees below forecasts, hitting only 28 degrees at Midway Airport with just 27 degrees recorded at the official O'Hare observation site. All the warmth and action occurred between 2000 and 3000 feet aloft over the city where southwest winds brought in 40+ degree air, establishing an extraordinary temperature inversion where readings increased from near 20 degrees F at 2000 feet to 45 degrees F at 3000 feet above the ground. The term "inversion" is used meteorologically to describe atmospheric conditions where temperatures actually increase with height instead of the normal decrease. The dense snow cover below along with light winds created this unusually stable environment that did not allow even a little of the normal mixing of air aloft with that on the ground.
Storms set to pound west coast
A 200 mph jet stream will direct a series of storms into the west coast during the week ahead. Total rainfall could range from 4 to 8 inches along the coast up to 10 to 20 inches in the foothills. Heavy snow will fall in the mountains, beginning at about the 5000 foot level. Snow accumulations up to 10 feet are forecast and that along with winds approaching 100 mph in mountain passes and higher terrain will create blizzard conditions bringing travel to a standstill.
Last weekend the upper-level steering wind flow was straight out of the north, directing cold air from the arctic regions of northern Canada directly into the Midwest and western Great Lakes. High temperatures last Saturday and Sunday were 22 degrees and 18 degrees respectively, averaging about 10 degrees below seasonal normals. This weekend the upper-air pattern has evolved significantly, taking on a more El Nino look. Steering-level winds are westerly with the Pacific Ocean as a source region, the Rocky Mountains providing a drying-out mechanism, and the major storm track is far to the south. As a result, high temperatures this weekend will reach the upper 30s, some 10 degrees above normal.
Rains confined to opposite corners of the nation
A major low pressure system has developed in southern Texas and will move northeast through the southeastern Gulf Coast states this weekend. Heaviest rains on the order of at least 2 to 3 inches will occur along a corridor from approximately New Orleans to South Carolina. At the same time, the first vestiges of a series of storms developing under a 200-plus mph jet over the Pacific Ocean and targeted to batter the West Coast all of next week will hit the Pacific northwest with an inch or more of rain this weekend.
A string of 314 consecutive hours of sub-freezing temperatures--the equivalent of 13.1 days---finally came to an end in Chicago Wednesday. The official thermometer at O'Hare registered at 12:21 p.m. its first 32-degree reading since New Year's Day. By mid-afternoon, a high of 35-degrees was on the books at the site. It was January's warmest reading to date and marked the first time in a stretch of nearly 20 days extending back to Christmas (Dec. 25) that daytime reading in the city had managed to break above freezing. Adding to the collective sigh of relief the warming produced across the metro area was the day's abundant sunshine. Wednesday hosted 100 percent of its possible sunshine making it the sunniest single day in 7 weeks.
Signs the tenacious arctic air mass behind much of the country's relentless streak of chilly air was losing its grip on the of the Lower 48 continue to grow. Satellite images were able to track the slow demise of the nation's expansive snow pack. National Oceanic and Atmospheric Administration (NOAA) scientists estimated that while 61 percent of the Lower 48 sat beneath a snowy veil Sunday, snow coverage had shrunk by 10 percent to just half the U.S. land mass Wednesday.
Biggest chill in decades finally easing after setting duration records in Florida
Across Florida and the Deep South, as damage to vegetation and crops--not to mention countless vacations taken by the winter weary who had headed south hoping to escape winter's wrath--was being evaluated, temperatures finally began a slow ascent from one of the region's most stubborn cold outbreaks in decades. A storm, which promised to deliver warmer south winds, began taking shape in the western Gulf of Mexico.
Sunshine State residents and visitors in Miami, West Palm Beach and Fort Myers rose Wednesday to a record-tying 12th consecutive morning with sub-50-degree temperatures while Gainesville and St. Simons Island, Ga. near Jacksonville, logged a record-breaking 12 days of sub-freezing readings. Every Florida weather station has registered temperatures 12-16 degrees below normal since Jan. 1.
Increased certainty storms threaten the West Coast with drenching rains next week
Evidence that formidable, wind-driven rainfall and high altitude snows are likely to lambaste the West Coast and Southwest next week became even more impressive Wednesday. Computer projections of potential rainfall in the coming two weeks--much of it to fall in an impressive parade of El Nino-strengthened storms next week--indicate more than 8 inches of rain may be on the way in sections of California. Such tallies would eclipse all the rain which has fallen to date since Oct. 1 in Los Angeles , San Francisco and San Diego. The heavy precipitation appears likely to extend into the Desert Southwest as well.
Arctic air is in retreat and not likely to occur here again until after next week. While winter's chill is hardly history--there are indications colder air may stage a comeback during January's final days in the week which follows-- the welcome development Wednesday closes the book on one of the coldest mid-winter periods in the Chicago area of the past 11 years. Since Dec. 26, the city's temperature has averaged 16.7-degrees--well below the 25.4-degree reading considered typical. Not since the 1998-99, cold season when readings averaged 13.6-degrees, has a comparable 18-day period been any colder.
But as chilly as the just completed near-three week spell has been, the meteorological winter season which began Dec. 1 is still running 1.5-degrees milder and nearly 10 inches less snowy than a year ago---28.3 inches this season versus 38.2 inches to date last year.
Temperatures surge above freezing Wednesday for the first time in the 20 days since Christmas' 43-degree high. The "warmth" comes on the heels of Tuesday's 31-degree peak reading---January's first above normal daytime high. It will establish a new high for the month, which until Tuesday, hadn't managed a reading above 30 degrees. On Thursday, afternoon readings appear poised to flirt with 40-degrees and are likely to do so at times next week as well. Historically, temperatures at or above 40 have occurred in 93 percent of Januarys and weather history reveals the year's opening month averages seven days with peak readings of 40-degrees or higher.
Increasingly stormy Pacific indicates Chicago's quiet precipitation pattern could end later next week
Huge waves already roam the Pacific and 16-day computer rainfall estimates suggest storms, expected to batter the West Coast with increasing frequency could deposit totals of 8 or more inches of rain in sections of California, the majority of it to fall next week. Computer models continue to produce eye-catching jet stream-level wind speed forecasts for early next week. The models suggest the El Nino-fortified jet expected to be roaring toward the southern West Coast at that time could boast rare 225 mph velocities at the 30,000 ft. jet airplane cruising altitude.
There's a relationship between the strength of high altitude winds and the storms which occur beneath them. Jet stream winds help produce the swift vertical motions which drop surface air pressures and lead to the flood of air which surges into vigorous storms. The stronger a jet stream's winds blow, the faster air ascends through the atmosphere. Low-level winds blowing into the storm must strengthen to compensate. Any storm which develops with a 200+ mph jet stream can be expected to produce especially strong winds and copious precipitation next week.
Already Tuesday, Pacific region forecasters were warning of possible 50 ft. breakers just off the shores of Hawaii in coming days and of 25 ft. swells along California coast--and this is days ahead of the most significant storminess expected to hit in a series of waves next week. The Navy's NOGAPS computer weather forecast model projects waves could approach five stories high in the Pacific just west of California next week, as the first surge of storminess related to the powerhouse 200+ mph upper winds surges toward North America's coast near California and Mexico's Baja California.
Arctic air's grip on Chicago's weather enters its 19th day Tuesday. But far-reaching changes in critical upper level steering winds taking place on a continental scale are to undermine the frigid air's dominance. The break in arctic-level temperatures may span much of the coming two weeks. Not until month's end may bitter winds of arctic origin return brutally cold air to the metro area.
Coming days will offer winter weary Chicago area residents a noticeable respite from the bitter air at the heart of January's 13.9-degrees average temperature to date--a reading more than 9-degrees below normal. But the "warming" predicted which is to include the city's first above freezing afternoon readings since Christmas (Dec. 25), may occur a bit more slowly than many might hope. The reason is simple. An uninterrupted cover of snow extending west 600 miles to the rolling plains of central Kansas and Nebraska, will reflect warming sunlight back to space as mild Pacific air surges into the Midwest. Were that snow not in place the incoming air mass would likely produce highs in the low and mid 50s here Wednesday and Thursday. Instead, Chicagoans will have to settle for mid and upper 30s. That's still quite an improvement over the 32-degree and lower readings which have dominated since Christmas Day--and more than enough to encourage some afternoon thawing.
The nearly three week period since cold air first arrived here has averaged more than 8-degrees colder than a comparable period a year ago and has boosted home heating an estimated 14 percent. During that time, the city's seasonal snowfall has surged to 28.3 inches--nearly twice (191 percent) normal---yet behind the 36.6 inches on the books a year ago.
Cold spell gripping Florida one of longest on record
Cold air of record or near record proportions has dominated most of the U.S. east of the Rockies all this month---and nowhere more dramatically than Florida. Historically, the Sunshine State has seen colder winter outbreaks---but few if any have lasted as long. Tampa recorded a 51-degree high Monday--the 10th consecutive day which failed to reach 60-degrees. Never over the term of weather records there (extending back 1890) has there been a longer spell of sub-60-degree temperatures. Many sections of the state recorded record-breaking lows in the teens and 20s early Monday. Miami's 62-degree high followed 48 straight hours below 50-degree temperatures--one of the longest sub-50-degree spells since records began in 1839.
Signs El Nino-like pattern could begin pounding California with powerful storms by next week
Longer-range computer projections place jet stream winds approaching the California coast early next week at a rarely seen 225 mph. Powerhouse storms become a real threat when jet stream winds grow that strong. Computer estimates of potential California precipitation over the coming 16 days---much of it predicted to fall next week--exceed 8 inches. Windy, wet West Coast storms are a hallmark of El Nino cold seasons.
A long-awaited and much-anticipated end to Chicago's prolonged cold spell is at hand, but a final surge of arctic air must first be endured. It arrives this morning, accompanied by a dusting of snow and northwest winds gusting above 25 mph. Temperatures start upward on Tuesday, and readings are forecast to break above freezing (32 degrees) on Wednesday, ending an 18-day string of days at or below freezing.
Southeast in deep freeze
Just as in Chicago, the Southeast is struggling through a prolonged cold spell. Unlike Chicago, the southeastern chill is establishing new record-low nighttime and daytime temperatures. Miami, with temperature records dating back to 1839, has recorded only five days with high temperatures below 50 degrees. Sunday's high of 48 degrees was the sixth, and its Sunday morning low, 35 degrees, tied a long-standing record for the date. Snow flurries visited Orlando Sunday afternoon, and Tampa had rain and sleet on Saturday and again Sunday. Cold-sensitive vegetation continues to suffer both from the intensity of the chill and from its multiday duration.
-- By Richard Koeneman, WGN-TV Meteorologist
Chicago has endured a prolonged cold spell and the city's temperatures have not been above freezing since the thermometer hit 43 degrees on Christmas Day. That was 16 days ago, and the city area has also had 14 to 20 inches of snow during that cold period. After widespread subzero readings early this morning in the coldest outlying locations, daytime temperatures, aided by abundant sunshine, are set to recover rapidly to the middle and upper 20s in the afternoon. A short-lived but nonetheless potent reinforcing surge of Canadian air arrives early Monday, accompanied by a dusting of snow.
Cold pattern breaks; warmer days ahead
All cold things must come to an end, and computer models of the atmosphere indicate Chicago's lengthy cold spell has just about run its course. A relatively mild flow of Pacific air is heading this way and should arrive Wednesday. The city's string of days with temperatures at or below freezing will end at 18 on Tuesday as readings on Wednesday surge well into the 30s. And that's the start of a new pattern of "mild" days.
We don't need to be told that we've been contending with a cold and snowy winter, but a review of Chicago's weather records reveals that it's been much worse on many occasions in the past. Through Jan. 8, this winter's average temperature, 23.9 degrees, ranks merely 28th coldest since 1870-71, 27 winters have been colder in the Dec. 1-Jan. 8 period; the coldest: 16.4 degrees in 1983-84. Seasonal snowfall through Jan. 8 stands at 28.3 inches sufficient to generate complaints from snow-weary residents, but only 8th snowiest. The greatest: 52.4 in 1951-52.
Lake snow smothers north Indiana
Lake-effect snows have been daily occurrences since Dec. 26 in the snow belt regions of northern Indiana. Snow totals there are impressive, even by the snowy standards of those areas. South Bend, Ind., recorded 23 inches during the first week of 2010, second only to the 27.3-inch total that fell during Jan. 1-7, 1999. Unofficial accumulations of 30-40 inches in the Dec. 26-Jan. 7 period have been reported in northern Indiana locations within 15 miles of Lake Michigan.
-- By Richard Koeneman, WGN-TV Meteorologist
Lake-effect snow falling at the rate of 1-2 inches per hour in southern Wisconsin Thursday evening was spreading south toward metropolitan Chicago. That promises to deliver several inches of additional snow on top of the 3-6 inches that had already blanketed the area Thursday evening. Morning commuters will have to contend with that.
Mild "El Nino winter" still possible
An El Nino event (abnormally warm ocean water in the equatorial Pacific Ocean westward from South America) is in progress and Chicago's "El Nino winters" are usually milder than normal. That's not been the case so far, of course, because winter readings thus far place December and early January temperatures among the city's colder 30 percent during that period. However, computer models suggest a major weather pattern change is likely to begin in 4-6 days. It's speculative at this point, but this might finally signal a break in the persistent pattern of sub-normal winter temperatures.
Before it's over and quiet weather returns, Chicagoans will have sampled the full range of the atmosphere's winter weather arsenal: storm duration (it's to be a 3-day event: Thursday-Friday snow, Saturday cold), significant snow totals, additional lake-effect snow, blowing and drifting, poor visibility, treacherous highway conditions, low temperatures, biting winds and subzero wind-chill readings. We've experienced far worse, of course, but that's little consolation to those who will be contending with the weather in upcoming days.
And the chill has penetrated into the Deep South. Jacksonville, Florida, registered 21 degrees early Wednesday, tying a record from 1884; Tampa hit 27 degrees, establishing a new record for the date.
Chicago's 10-inch snowstorms
Chicago weather historian Frank Wachowski informs us that the city's winter-weather climatology (spanning 125 snow seasons from 1884-85 through 2008-09) includes 43 storms that produced at least 10 inches of snow - on average, one such storm every three years.
The weather just won't give us a break. It's been cold for several days, and with an average temperature of 11.0 degrees, it's Chicago's 17th coldest Jan. 1-5 in 140 years. The persistent chill has set the stage for a snowstorm that promises to become the season's biggest to date. Snow arrives here this evening and continues overnight, finally diminishing to flurries by Friday morning. The snow, falling in an especially cold environment, is likely to be "fluffy," with considerably less water content that usual. And as an added kicker, moisture from Lake Michigan may add 2-5 inches to local accumulations.
Major snowstorm in Seoul, South Korea
A sudden winter storm on January 4 blanketed portions of the Korean Peninsula with record snows. Seoul received 11-12 inches, the city's greatest single-day snowfall since Korea began conducting meteorological surveys in 1937. Beijing, China, received 3 inches in the same storm and that was its greatest one-day total in 59 years.
No relief is in sight for area residents growing weary of the extended cold spell. Temperatures are set to remain cold into mid-week, and then a new storm is likely to blanket the city with a half-foot of fluffy, low-water-content snow late Wednesday through Thursday. But that's not the end: Another strong surge of arctic air follows the snow and temperatures dive.
Even Florida is freezing
It is not unheard of for Florida - even south Florida -- to experience brief periods of freezing or near-freezing temperatures each winter. Even coastal areas and coastal cities like Miami average a light frost every five years or so. Typically, though, the cold snaps rarely last beyond two days. What is noteworthy about the current cold spell is the duration of the event. Florida is likely to experience much below-normal temperatures and nighttime freezes and frosts for a period of seven days before the weather breaks. The Miami National Weather Service advises that will be the state's longest cold stretch in 15 to 25 years.
The cold has been relentless since the day after Christmas and it's likely to continue for another week. In the short run, we'll experience incrementally higher temperatures through mid week before another reinforcing surge of arctic air accompanied by a few inches of snow arrives early Thursday and extends the life of the cold spell through the weekend.
A string of nine consecutive days with maximum temperatures no higher than 25 degrees will have been tallied by Jan. 9, but that won't challenge the record: We experienced 17 consecutive days at or below 25 degrees from Dec. 16, 1983, through Jan. 1, 1984.
Lake-effect snow piles up
Cold air blowing across Lake Michigan has been depositing impressive snows in the snow belt areas of north-central Indiana and southwest Lower Michigan. Local 28-inch totals had accumulated in Michigan's Berrien County by Sunday evening, and heavy snow was continuing. Totals approaching four feet are possible by midweek.
-- By Richard Koeneman, WGN-TV Meteorologist
The cold spell that we are experiencing is noteworthy not for the intensity of its chill - we've experienced much worse -- but for its persistence. Ten 10 days will pass before significantly higher temperatures arrive. And Saturday was perihelion day, the day on which the Earth makes its closest approach to the sun in its annual orbit about the sun.
We're not alone in our cold-weather discomfort. Very cold air holds all of the nation east of the Rocky mountains in its frigid grip -- fully two-thirds of the Lower 48.
Surges of lake-effect snow swirling off Lake Michigan continue to cause problems for residents of the snow-belt areas of northern Indiana and southwest Lower Michigan, but they take that in stride even as local accumulations exceed 20 inches by Sunday night.
The chill plows south
Residents of the Deep South, however, are less accustomed to harsh winter conditions. Sub-freezing temperatures are pushing into northern Florida. Even Cuba is experiencing unseasonable chill.
The atmospheric flow pattern at high as well as low levels aloft will take an almost direct path from the coldest regions of the Arctic south through the Canadian Provinces of Manitoba and Ontario into the western Great Lakes and Midwest. Even though the air will pass over snow-covered soils almost the entire route, it will modify somewhat with time. Saturday's forecast high of 9 degrees will be the coldest high temperature in Chicago since a 3-degree high observed almost a year ago Jan. 16. Chicago's daytime highs should be nearly 20 degrees below average this weekend and some 10 to 15 degrees below average next week. During this period, wind chill values will consistently run from the single digits to subzero.
Snow confined mainly to the Snowbelt
With a persistent northwest wind flowing over the Lake Michigan waters, almost continuous snow will fall along and inland of the northwest Indiana and western Lower Michigan shoreline. While snowfall totals in the snowbelt could range from one to three feet in the next seven days, current forecasts have a significant chance at snow for Chicago and northeast Illinois occurring only with the passage of low pressure to the south later Wednesday and Thursday.
