Thursday’s 27° high was the chilliest close to a meteorological autumn here in 22 years—since a 24° high on Nov. 30, 1983. That this past season closed as chilly as it did is ironic, considering the three month period from September through November finished well above normal—the 19th warmest of any since 1871.
The chill sets the tone for December’s opening week, expected to average nearly 12° below normal. North winds behind a series of vigorous, snow-producing disturbances predicted to sweep the area in the coming week, pull successively colder lobes of arctic air into the Midwest off a vast reservoir of frigid air which covers the central U.S. and north. These cold pushes promise to produce a succession of daily temperature deficits through at least next week. If predicted temperatures verify over the next seven days, December, 2005’s opening may rank among the Top 10 coldest on the books here.
November 2005 Archives
Despite Wednesday’s emerging sunshine, the arrival of new clouds later today signals the approach of what is likely to be the first in a series of snow systems starting late Wednesday night. By Thursday morning, as December 2005 and the first hours of meteorological winter arrive, 1-2” of snow may fall. Given the strong upper air features and cold temperatures accompanying this system, it’s even possible a few 2-3” totals may occur. Such accumulations would be the heaviest recorded the first day of December since 2.7” fell 26 years ago in 1979.
Factoring in the day’s blustery SW winds, Tuesday’s temperature plunge produced a level of chill which felt 44° colder. Actual thermometer readings plummeted from 61° to 28° in just 30 hours from noon Monday to 6 p.m. Tuesday. The pullback was the equivalent of the decline in normal temperatures which takes place between late October and mid-January.
--Tom Skilling
The weather was in rare form here with 60° temperatures Monday—but downright brutal across the Plains, a region lashed by blizzard conditions. So fierce were wind gusts there that dust and soil were mixed with the falling and blowing snow. Goodland, Kan. recorded its 9th windiest day ever since 1896, logging 64 m.p.h. wind gusts. At nearby Ruleton, winds reached hurricane force, topping out at 77 m.p.h. Flagler, Colo. clocked 79 m.p.h. winds. Farther east, sections of northeast Nebraska were coated with a thick layer of ice after 1” of freezing rain and sleet hit the area only to be followed by 8-13” of snow whipped by 50-60 m.p.h. gusts. Topping reports of snowfall was the 14” reported at Gregory, South Dakota. There, 50+ m.p.h. winds built 5 ft. drifts.
Chicago’s 61° high Monday morning was only the 89th reading in 135 years to pass 60° this late in the season. Of the 4,590 total highs at or above 60° on the books here since 1871, fewer than 2% occur November 28 or later.
Blizzard conditions seriously hampered travel Monday across a wide swath of the central and northern Plains. These pictures tell the story, capturing the fury of the late autumn storm's winds over western Kansas. Lead Forecaster Mick McGuire of the National Weather Service Forecast Office in Goodland, Kansas is good enough to share these with us. He snapped them in the midst of the storm's howling backside winds just before midday. The 3-4" which fell there were whipped into drifts 3.5 feet high by winds which gusted from 60-77 mph. Meteorologist Al Pietrycha, formerly of the Chicago NWS Forecast Office and now in the Goodland Office, tells us he's not easily impressed by wind gusts under 100 mph. But, Monday's winds were among the exceptions. He noted that wind gusts reached 79 mph at Flagler, Colorado--to the west of Goodland. "I've never had my electrical power go on and off so many times in one day," said Pietrycha of Monday's storm. He tells us the winds of Monday's blizzard far exceeded the BIG blizzards he had experienced in Connecticut in 1977 and Colorado in 1997.
Chicago’s windy, rainy warmth this morning will be short-lived as a sharp temperature downturn begins this afternoon when a strong cold front passes through the city. High temperatures the rest of the week will get no higher than the 30s, and overnight lows will drop into the 20s and eventually into the teens. Flurries are likely here on Tuesday with prospects for a shot of light snow with a system passing through the city on Thursday.
On Sunday afternoon, an intense low brought a rash of twisters to the central Plains, while blizzard conditions raged in areas to the west.
As many as 15 twisters struck on the warm east side of the storm in eastern Kansas with several reports of property damage. On the storm’s cold western flank, heavy snowfall and strong winds created blizzard conditions that resulted in a 25-car pile-up that shut down portions of Interstate 70 in eastern Colorado.
A strong late-autumn storm taking shape in the central Plains this morning will take Chicago’s temperatures on a wild roller coaster ride today through Monday. Boosted by increasingly strong southeast and south winds, readings will surge into the lower 60s later today and hold in the 50s tonight as waves of showers and even some thunderstorms roll through the city. South winds will howl Sunday night, gusting above 40 m.p.h. with the risk of damaging winds as potentially severe thunderstorms rock the city around daybreak Monday.
Temperatures will drop steadily Monday and Monday night back to more seasonable levels in the 20s and 30s.
Areas west and north of Chicago face a much different fate from this storm. Winter storm watches and warnings are posted across portions of seven states from Nebraska to Upper Michigan for a wintry potpourri of heavy snow and freezing precipitation.
Ongoing atmospheric changes as Saturday gets under way eject frigid arctic air and put in motion a dramatic 50-degree three-day temperature surge. The warming is the equivalent of a move from January to late April, only it’s condensed over a fraction of the time. From Friday morning’s 13° reading, temperatures surge to 45° Saturday and to 62° Sunday afternoon or evening. That’s shy of Sunday’s 67° record high set in 1990, but it’s still an eye-popping 20 degrees above normal—mild enough to rank among late November’s top 15 percent warmest readings on record since 1871. Friday’s 25° high was the second coldest for Nov. 25 in 135 years.
Mild air surging over retreating arctic air produced Friday evening’s dusting to 1” of snow here. But, far larger snow totals have been reported downwind of the Great Lakes. Marquette, Mich., has picked up 16.3” of snow since Wednesday, which brings its monthly total to 39.3”—that’s 22” above normal.
Winds gusted to 43 m.p.h. Thursday amid frigid January level temperatures averaging more than 20 degrees below normal. By nightfall, windchills in the area had hovered near 0° for 15 consecutive hours—and were expected to continue in that range all night. Though Thursday’s mildest temperature of 41° occurred at midnight, readings had plunged to the teens by daybreak, making it the coldest Thanksgiving daytime temperature here since the upper teens recorded in 1945. Wind gusts hit 61 m.p.h. at Chicago’s shoreline at the Harrison-Dever Crib.
Blizzard conditions Thursday led to the closure of the Mackinac Bridge for a time in northern Lower Michigan. Travel over parts of the state’s Upper Peninsula was halted by whiteout conditions brought on by nearly 50 m.p.h. gusts. The 17.8” snow tallies at Rudyard and Kinross (southwest of Sault Ste. Marie) were records for the date, while 10-12” fell near Traverse City and 6” was down on Michigan’s western shoreline.
There hasn’t been a Thanksgiving this cold in Chicago since 1956. A potent early season arctic outbreak has arrived on powerful northwest winds—stacked vertically through the atmosphere and the underbelly of a 180 m.p.h. northwesterly jet stream roaring into the country from Canada.
Surface wind gusts in excess of 40 m.p.h. at times will slash daytime temperatures 20 degrees from yesterday’s levels in the mid 40s.
Afternoon thermometer readings are likely to linger in the upper teens or low 20s—but wind chills will hold to single digits and near or just below 0° at times.
The frigid air which grips Chicago Thursday had origins 1,200 miles to the north only 24 hours ago. Its descent into the United States crushes the record warmth recorded in the Plains Wednesday. Records included 69° at Rapid City, S.D. and Hastings, Neb.
WGN-TV meteorologist Richard Koeneman sent these pictures of a "surprise" snow in North Carolina. An upper low lifted northeast right across western North Carolina, and the cold pool of air in the mountains was just chilly enough to turn the rain over to snow last night, with totals of up to 3 inches. These pictures were taken about 10 a.m. Tuesday, with a temperature of 29º. The snow started falling with a surface air temperature of 35º, so it stuck to everything.
After the snow/rain event ended, Richard sent us an updated snow total of of 4.2 inches and a total 1.54" of water-equivalent precipitation -- welcome moisture after the mini-drought of September and October in that area of North Carolina.
Richard also sent us a picture of him with his fellow "doggie" meteorologists: Buddy (the big white one), Sadie (the little tiny one) and Maylee.
Plunging temperatures and powerful northwest winds promise Midwesterners a very cold Thanksgiving Thursday. Readings dive more than 20 degrees between Wednesday’s mild 40s once daybreak snows move on, and the frigid teens to mid 20s predicted Thursday. Gusts above 30 m.p.h. are to hold wind chills to single digits. Not since Thanksgiving 1956, when temperatures struggled to 25° and winds averaged 28 m.p.h. with 35 m.p.h. gusts has the holiday been any colder here.
More serious weather woes loom downwind of the Great Lakes for residents and travelers there. Lake-effect snow, a “no-show” in north-central Indiana and southwest Michigan Tuesday, is to make up for lost time beginning Wednesday night. Waves of snowfall over the coming two days could lead to 12”-plus accumulations at some locations. Blizzard conditions are predicted in Upper and northern Lower Michigan with powerful 50 m.p.h. gusts.
Lake snows whiten sections of northern Indiana’s snowbelt east of Porter County and north into western Lower Michigan Tuesday. Such snows fall with the greatest intensity when incoming winds have traveled farthest over open lake water. But Tuesday’s winds are to back from NNW to NW with time. This means the lake snows they support will move with time, limiting the period of most significant snowfall in any one area. This should prevent gargantuan totals. The hardest hit areas should see 3-5”—locally a bit more. These totals threaten hazardous travel conditions around the southeast end of Lake Michigan.
Much colder air hits late Wednesday night through Friday and lake snowfall in that outbreak could be more substantial, focused again on areas east of Chicago.
Incoming mild air sets up an area of overrunning light snow Tuesday night. This threatens to dust a broad swath of the Chicago area with a trace to as much as half an inch of snow.
-Tom Skilling
A cold front will move through northeast Illinois this afternoon, setting the stage for a significant drop-off in temperatures for the rest of the work week. Temperatures for the Tuesday-Friday period will average about 10 degrees below normal with the coldest day Friday when readings will probably fail to warm out of the 20s.
Light snow or flurries will be in the forecast almost daily, and with winds mostly on a northwest trajectory, heavy lake-effect snows around the south end of Lake Michigan and Northwest Indiana may develop, especially Tuesday and Friday.
Holiday travel to the northeast may be problematic, as the persistent upper air pattern dominating the eastern Northern Hemisphere responsible for our wintry chill here will impact western Pennsylvania and New York with heavy snows.
Arctic air is on hiatus this weekend after producing subfreezing temperatures for 52 bone-chilling hours. Temperatures recover noticeably Saturday despite gusty winds. Area readings near or just above 50° appear a good bet and may reach the low/mid 50s in the warmest locations. That’s a surge of 22 degrees over Thursday’s frigid January-level 28° high.
By late Friday, the powerful cold air outbreak had slashed the month’s temperature ranking in Chicago 20 slots—from 12th to 32nd warmest of 135 Novembers on record. And, at least two strong new surges of arctic air next week (after Monday) threaten to further depress the ranking.
Readings first fell below 32° at 7 a.m. Wednesday, then remained below freezing through 11:30 a.m. Friday. Winds gusted above 30 m.p.h. during at least half of that 52-hour stretch, producing a long string of single-digit wind chills. Only 21 other years since 1871 have hosted such cold weather so early in the season.
Chicago Tribune photographer Joh Smierciak, on assignment southwest of Peoria on Rt. 136 near Havana, Ill., captured cold frontal storm clouds as dozens of twisters raked sections of 6 states, including downstate Illinois and Indiana. NOAA's Storm Prediction Center tallied 37 reports of twisters in that day's severe weather outbreak. November ranks deadliest of all months this year in terms of tornado fatalities.
–Tom Skilling
Frigid arctic air and abnormally warm Great Lakes water temperatures proved an explosive combination Thursday, setting the stage for this autumn’s heaviest lake snows. Areas of Michigan opposite Chicago were buried. Grand Rapids was hit by 8.4" while 7" fell at Sparta and 7.5" accumulated late Thursday at Scottville in southwest and west central Michigan. Farther north, snow totals were even more impressive. Traverse City sat beneath 11" by nightfall while nearby Interlochen reported 13"—and snow was still falling.
But, it was Michigan’s Upper Peninsula which boasted the heaviest totals of all. Marquette’s 17" paled in comparison to the 27" full workweek tally at Ironwood since Monday night.
Thursday’s 28° high in Chicago was the coldest here since March 2 (27°). That level of chill didn’t occur a year ago for another month.
Bitterly cold air, trapped for three weeks over Alaska and the Yukon, cut loose and roared south all the way to the Gulf of Mexico Wednesday.
The teens which greet area residents Thursday morning occur this early in fall on average only once every 17 years.
Chicago temperatures plummeted Tuesday night and Wednesday 33° in just 24 hours —from 55° to 22°—a drop equivalent to the change in normal daytime highs from late October to January. The plunge was accompanied by 24 consecutive hours of 30+ m.p.h. wind gusts which generated single digit wind chills. Coming as it did after one of the mildest November opens on the books (12th warmest of the past 135), the change was a brutal one. And the early season chill continues Thursday. A predicted high of 30° is to make November 17 the fifth coldest ever and the coldest for the date since the 14° high 46 years ago in 1959.
Dozens of twisters hopscotched across at least five states Tuesday in the third major severe weather outbreak of the past two weeks. It was the single biggest tornado count since Hurricane Rita’s remnants roared ashore on September 25, producing 47 twisters. The number of tornadoes Tuesday had reached 35 by late evening. And forecasters feared an active 1,600 mile long squall line, extending from the south Texas Gulf Coast north to the Detroit area, would produce more. November, 2005 now ranks as the the deadliest month of 2005 for tornadoes, having produced 22 fatalities. Flooding 5-10” rains were reported in southern Illinois--including 4.51” at Carbondale.
To Chicago’s north and west, wind-driven snow fell amid plummeting temperatures. Snowfall reached 6.2” at Elcho, 4.5” at LaCrosse and 4” at Wisconsin Dells—all in the Badger State—and was still accumulating beyond sunset.
Threat of severe storms ends here, but major severe outbreak underway to Chicago's east; more than two dozen twisters already reported
The threat of severe thunderstorms is over in the Chicago area. Strong winds, falling temperatures and 3-6 hours of dry weather are immediately ahead--then snow showers arrive in Wednesday's pre-dawn hours. The precipitation-free weather soon to take hold and last half the night, is the result of the larger storm system's "dry slot", as mentioned in the previous update. This is a very windy but dry region of any largescale storm. But the feature migrates and snow showers are likely here as it exits the area before daybreak Wednesday.
While the severe weather threat has ended here, a major severe weather outbreak is underway across a good part of the nation's mid-section to the city's south and east. More than two dozen reports of twisters have already been tallied by NOAA's Storm Prediction Center this afternoon--and more are likely as we head through the evening and the night. Southern Indiana, extreme southern Illinois, western Kentucky and western Tennessee have been hardest hit through 5:30 pm. Now the focus is on a powerful squall line with cloud tops from 37,000 ft to 52,000 feet is sweeping northeastward through Indiana and southeast Michigan--and is headed for Ohio. It is part of a long line of powerful and severe thunderstorms which extend south to the Gulf Coast, where storms are crossing the Texas coastline into the Gulf of Mexico. We expect a number of additional tornadoes is likely to be reported from these areas. There are four active tornado watches in effect from Lousiana north to Detroit and a series of severe thunderstorm and tornado warnings are in effect as this update is filed.
Snow is sweeping across Iowa on winds which, in the western half of the state, are gusting 40+ mph. Temperatures have plunged into the low and mid 30s across all of Iowa. It's this chilly air which is to take up residence in the days ahead--part of a radically different pattern which may feature regular outbreaks of chilly air the remainder of November---a month which until now has been so mild it ranks 12th warmest of all November 1-15 periods on record here since 1871.
--Tom Skilling
The temperature plunge headed for the Chicago area is evident in these snowy shots from meteorologist Dean Wysocki of Omaha shot today (Tuesday, November 15).--Tom Skilling
4 P.M. TUESDAY
A period of strong thunderstorms or downpours--perhaps even a spell of
severe weather---threatens parts of the Chicago metro area early this
evening just ahead of this autumn's latest powerful storm's "dry
slot"--the narrow notch of dry air evident in the comma shaped cloud
mass visible on satellite imagery with storm's like today's--shifts
into region. If a weather watch is to be issued for any part of our
this area, it is likely to happen before 6 or 7pm--or not at all.
The latest computer model depictions of the intensifying storm
confirm a 60 mph band of southerly winds just 1,600 ft. above the
surface and advancing on the area from central and southern Illinois
and expected to converge with the 10-20 mph ESE winds currently in
place here between that time. Known as "speed and directional
convergence", the pile-up of air which results from this type of
situation, leads to vigorous upward motion through the atmosphere--in
today's case, into a 155 mph southwesterly jet stream. Thunderstorms
able to form in this type of situation are prolific rain producers,
capable of downpours and hailstones. But they move quickly in the fast
steering wind regime in place aloft. Any gusts they produce
effectively incorporate the storm's rapid forward movement with the
storm's outflowing winds which makes these gusts potentially extreme
and damaging. It should be noted, these gusts are best able to make it
to the ground when a cooler air isn't in place in the lower
atmosphere--as is the case at the moment as this update is filed at
mid-afternoon. So one key to the potential to high wind production
here will be whether a warm front can briefly pass, placing
Chicago--even if briefly--in the intensifying storm's "warm
sector"--which isn't likely to be very warm here at all, and certainly
not for very long since cold air is waiting in the wings
. 70-degree temperatures and mid 60-degree dewpoints (indicative of
humid air) are in place downstate and are helping fuel t-storm
development there. A major severe weather outbreak threatens a broad
area, especially to Chicago's south. The Storm Prediction Center has
an 8 state area designated as a "high" risk region---not an everyday
occurrenc---and a testament to the current storm's strength.
Meantime, snow and wind on the storm's backside sweeps into Chicago
after a 3-6 hour precip-free period in this storm's dry slot tonight.
Snow showers and flurries appear likely to sweep into Chicago in a
sharply colder and very windy weather regime by daybreak Wednesday and
through a good part of the day. Snow accumulations over sections of
northern Wisconsin and Upper Michigan threaten to exceed 6-8" and the
snow, though falling on warm ground and pavement, the speed at which
snow falls there should be impressive. Snowfall rates here and
temperatures just above freezing in Chicago shouldn't allow
significant accumulation.
Powerful winds and wind chills in the 20s are predicted
Wednesday---a day likely to be the first this autumn in which
temperatures aren't able to reach, let alone exceed 40-degrees. This
should be the coldest day in the nearly 8 months March 21.
Interestingly, the average first date of sub-40-degree occurrence each
fall is on November 9--putting tomorrow within a week of that time.
We'll have much more on this and what looks like a colder overall
pattern likely to last awhile tonight on the WGN 9 O'Clock News. All
the best!
---Tom Skilling
With the city still reeling from Sunday’s 50 m.p.h.-plus wind gusts that brought a rash of power outages and tree damage, and central Iowa sorting through tornado damage, another potentially blockbuster November storm is gathering forces in the southern Plains. In Chicago, the storm’s impact should begin late tonight as rain and thunderstorms move in, accompanied by strong, gusty southeast winds. This storm poses another severe weather threat to the lower Mississippi Valley and the southern Midwest, and it will be followed by another round of high winds on its cold backside Tuesday night and Wednesday.
Temperatures here should plunge Tuesday night, allowing the rain to become mixed with wet snow. Wednesday should be downright wintry with snow showers, strong northwest winds and temperatures holding in the 30s—a far cry from our recent balmy days in the 60s.
An outbreak of tornadoes hop-scotched across portions of central Iowa late Saturday afternoon touching down in areas from west of Des Moines to north of Ames. No deaths were reported but extensive damage occurred in Woodward, just northwest of Des Moines. Ironically football fans at the Iowa State Cyclones’ game against Colorado were evacuated as the twisters approached the stadium at Ames. Hail, up to the size of tennis balls, also pelted the central Iowa area.
The Iowa storms and Chicago’s windy and rainy Saturday were the forerunners of an impending cold blast headed for the Midwest. Chicago’s extended warmth of Fall 2005 will come to an abrupt end this week as a blustery cold blast replete with the season’s first snow showers moves into the city.
Readings that soared to 60º or higher on 10 of the first 12 days this month will be a distant memory by Wednesday when afternoon highs should not even reach 40º.
Powerful winds sweep the area Saturday, gusting as high as 40-50 m.p.h. in the afternoon and evening. Winds of that strength are capable of producing some damage. The third autumn storm in a week is behind the high wind threat. Only days ago, waves of rain associated with this system drenched mountainous sections of southern California with 5”+ of rain. The storm’s trek across the Rockies delivered 4-8” of wind-driven snow to Colorado Friday, allowing some ski resorts to open. At the same time, the system’s warm south winds sent temperatures soaring 32 degrees above normal across the Plains, setting records at Mitchell, S.D., (77°); Bismarck, N.D. (70°); and both Valentine and North Platte, Neb. (82°).
Chicago closes in on its 1949 record of 70° Saturday, a level 20 degrees above normal. For the 10th time in November’s first 12 days the mercury will exceed 60°. That’s only happened once before between Nov. 1-12—in 1964.
Chalk up another first for 2005. Never until this year has Midway Airport gone 226 consecutive days above freezing—at least not since observations began in 1928.
This year’s persistent warmth is behind the new record. The streak of above-freezing days ended early Thursday when the mercury dipped to 31°—the first sub-freezing temperature at the South Side site since March 28.
The period which elapses between the final freezing temperature of spring and the first 32° of autumn—roughly the period between killing frosts—is also referred to as the growing season. Freezing temperatures at O’Hare first occurred Oct. 23, bringing an end to the growing season there 2-3 weeks earlier than Thursday’s close at Midway. The 226-day period above 32° was 47 days longer than the comparable period a year ago.
A sharp temperature rebound in the Plains Thursday will reach Chicago Friday afternoon—boosting readings here by 15 degrees.
Lake Superior churned under the influence of November gales Wednesday, much as it did 30 years ago when the Edmund Fitzgerald sank in estimated 30 foot seas on the Big Lake. In each case, an intense autumn storm was involved. Wednesday’s system fell a bit short of the November 10, 1975 storm, which took the ore carrier to the bottom. But, gusts reached 70 m.p.h. over open water 50 miles east of Upper Michigan’s Keewenaw Peninsula and 66 m.p.h. at Houghton County Airport—powerful enough to generate 15-20 foot swells.
The same storm’s winds whipped the Chicago area as temperatures tumbled Wednesday. Gusts reached 39 m.p.h. at O’Hare (36 m.p.h. at Midway), Fall 2005’s second strongest wind to date. The powerful flow delivered early season arctic air, slashing temperatures more than 20°—from 66° at midnight to 42° by 10 p.m.
-Tom Skilling
THIRTY YEARS AGO
On duty in the midst of a tragedy—Sinking of the Edmund Fitzgerald
Thirty years ago during the early evening hours of November 10, 1975, I was on duty as an aviation forecaster at the Chicago office of the National Weather Service. I was teamed with Lead Forecaster, the late Jim Vermoch, and we analyzing the 6 p.m. CST surface weather map. An intense storm system was moving through the upper Great Lakes and storm warnings for winds in excess of 55 m.p.h. were posted for Lake Superior. Earlier in the day strong winds had been blowing out of the east piling up huge westward moving waves on the lake, but now in the early November darkness howling west winds often reaching hurricane force (74+ m.p.h.) were creating monstrous waves in the opposite direction.
About 7:30 p.m. the "Green" phone, an internal hot-line used for forecast coordination, rang. I answered the call and found myself speaking to the Coast Guard duty officer in Sault Ste. Marie, Michigan. He told me that he believed a ship on Lake Superior had gone down that evening during the storm. He thought it was named the SS Fitzgerald. I relayed the information to Jim Vermoch and we quickly made calls to the Meteorologist-in-Charge of the office, Ray Waldman and to our regional headquarters in Kansas City, Missouri. At that time, neither of us had any idea of the magnitude of the marine tragedy that was unfolding before us.
The next morning all the horrific details of the tragedy were becoming available. A large iron ore carrying vessel, the Edmund Fitzgerald had disappeared in Lake Superior 17 miles northwest of White Fish Point, and it was almost certain that all 29 men on board had perished.
As they say, the rest is history.
Photo: Courtesy Meteorologist John Dee
Thursday (November 10) marks the 30th anniversary of the Edmund Fitzgerald disaster on Lake Superior in 1975. Nearly three decades later, much of the Midwest, including Upper Michigan and the waters of Lake Superior, were whipped Wednesday by gale force winds--the product of the latest autumn storm to sweep the nation's heartland. Meteorologist John Dee of the U.P's Keeweenaw Peninsula has provided us this photo of Lake Superior's wind tossed waters (taken at the breakwater at the upper entry to the Keeweenaw Waterway) and reports 40-50 mph winds have blown at Houghton County Airport much of the late morning and afternoon Wednesday. Gusts there reached 66 mph at one point while Stannard Rock (located in Lake Superior 50 miles east of the Keeweenaw) reported a gust of 71 mph. Waves on the Big Lake have been running 15-20 ft. Our thanks to John for the picture and information!
--Tom Skilling
A northbound warm front ignited active thunderstorms earlier this evening responsible for lightning which struck a residence in west suburban Sugar Grove around 9pm. Firefighters were dispatched in response to the fire which resulted. Radar scans placed cloud tops as high as 36,000 ft. Other powerful thunderstorms have raked sections of Indiana and Michigan. Hailstones 3/4" to 0.88" in diameter peppered Hartford City and Marion, Indiana.
The warm front's passage has placed Chicago in milder, more humid air—a sector still capable of severe weather production given many of the attributes of tongith's atmosphere already discussed. But of particular interest are powerful non-thunderstorm wind gusts sweeping eastward out of the Plains and due to take up residence here daytime Wednesday. These winds are raking across central Iowa and expected to reach the Chicago area toward morning. The convergence (pile-up) of air taking place ahead of these powerful winds may ignite another line of active, possibly severe thunderstorms—even a few isolated tornadoes—which could reach the Chicago metro area between 2 and 4 am. Once they pass, strong, non-thunderstorm winds are likely Wednesday with gusts to 40 m.p.h. not out of the question.
-- Tom Skilling
Midwesterners haven’t seen the last of this month’s thunderstorms. More arrive Saturday night into Sunday—and still others are predicted next Tuesday. Additional thundery weather in Chicago would bring the city’s tally of thunderstorm days this month—already the most in a November since four occurred 17 years ago in November, 1988—well above the single thunderstorm considered normal.
With record warmth so dominant this month, the huge spread in temperatures across the continent continues to support a powerful, storm-transporting jet stream draped just south of the U.S.-Canadian border. Wednesday’s gusty NW winds are being driven by the latest storm embedded within that flow. More than four dozen cities in 17 states set new temperature records Tuesday. Among them, St. Louis topped out at 82° while Austin, Texas hit 88°.
-Tom Skilling
Issued 2PM TUESDAY -- I want to update you on the potentially potent severe weather situation--including the threat of powerful thunderstorms and tornadoes---which appears to be coming together for tonight.
There are never guarantees a given set-up will go on to produce violent weather, strong as it may appear. And, even when it does, such weather is highly selective--damaging often damaging one area and sparing another. We have no skill yet in meteorological science to tell you many hours in advance precisely which communities are at risk. But, the current situation has an ominous look to it and is worth flagging--even if it ends up passing quietly.
It must be said up front that our in-house review of storm records indicates only 2% of all the tornadoes which have occurred since 1950 in the 16 counties which include and surround Chicago have occurred in November. So, the probability of a tornado at this time of year is comparatively low historically and the prospects of such a thing happening at night would appear to further reduce the possibility of occurrence because of the absence of critical daytime heating. But, that doesn't mean it can't happen--and there appear to be compensating variables capable of encouraging storm development despite the late hour. We need only look at what happened this past week in southern Indana to remind ourselves nocturnal severe weather is entirely possible, even at this time of year. As mentioned in our vignette piece this morning (Tuesday) on the developing weather situation which ran here on our weather blog and on our Chicago Tribune weather page this morning, Dr. Joe Schaefer, Director of the Storm Prediction Center tells us nocturnal (nighttime) severe weather is often a feature of many late season storm outbreaks.
We've been monitoring this situation for several days and continue to be concerned at what we see. Severe thunderstorms and tornadoes are all to often notoriously fast-developing and the atmosphere continues to give us strong signals it's poised for a significant eruption later this evening and tonight. Our best thinking is that the period from 8 p.m. to 12 midnight warrants special vigilence for it's during this interval of time the meteorological elements of storm production come together over northern and central Illinois, southern Wisconsin and northern Indiana. The hours immediately surrounding 8 to 12 p.m. must be monitored as well. (Those farther east in Indiana, Michigan and Ohio are likely to face these storms even later tonight). If anything's going to happen, that appears to be the period during which rotating, supercell thunderstorms are most favored to erupt. A layer of cool, fairly stable air hugging the surface north of an incoming warm front is the one variable forecasters are monitoring most carefully. Such layers have been able to extinguish the low-level thunderstorm circulations necessary to spin up tornadoes, even while allowing thunderstorms to produce other severe weather attributes. The belief at this point is that other meteorological variables may prove strong enough to render the shallow layer less a factor in this case--but time will tell.
Here are the factors which make Tuesday night vulnerable to severe weather development. Unseasonably warm air to Chicago's south is loaded (by late season standards) with moisture which provides the fuel for thunderstorm development. Dewpoints in the low/mid 60s have advanced north to Quincy and Springfield as of the time of this release. (It's already 80-degrees downstate in St. Louis versus 58-degrees in Waukegan). At the same time, the the air is dry in central and western Kansas and Nebraska with dewpoints only in the 20s and 30s. Upon sunset, the humid air will remain warm while the dry air to the west will cool precipitously, strengthen the already strong southerly winds blowing over Missouri and Kansas. As these moist, strong SSW winds intersect a warm front, along which Chicago and northern Illinois' easterly winds converge with the strong SSW winds to the south, a powerful "lift" will occur, cooling the air and supporting thunderstorm growth. This convergence will enhance the upward flow of air into an unusually unusually powerful WNW jet stream aloft. SSW winds in the lower atmosphere and WNW winds aloft increase the tendency of air to rotate as it ascends. Shifting wind direction with height is called "vertical wind shear" and serves as a critical component of severe storm development. What's more, temperatures are falling more quickly than usual with height indicating an "unstable" atmosphere--one in which air is encouraged to rise and keep rising. As an intensifying low pressure approaches from the west with a cold front later Tuesday night, powerful WNW winds behind it increase the lift by converging with the south and east winds on the storm's east side. As all this happens, a pocket of powerful jet stream level winds races in from the west--with a tendency for these winds to diverge ("split") over this area.
Diverging high level winds signal an upwelling of air on a fairly large scale from below--not a good sign. Put simply, the situation appears explosive and must be monitored.
The ominous confluence of factors is to race east and out of the area well before sunrise. One of the cooler air masses of Fall, 2005 follows.
-- Tom Skilling
In only 13 of the past 136 years have Chicagoans enjoyed warmer temperatures in the opening 7 days of November. Though cooler easterly winds have replaced Monday’s mild, gusty southwest flow, the first week of the month ranks as the warmest here since 1978 and the 14th warmest of the last 136 Novembers. The period’s 53.4° average temperature has soared 7.7° above the long term average dating back to 1870. Departures of that magnitude have a way of not lasting. One of Fall 2005’s coolest air masses to date arrives for a short stay later Wednesday into Friday morning. But warmth returns Saturday and may include Chicago’s third November 70°.
The current pattern may be showing the first signs of fatigue in the 1-2 week range. A chunk of frigid air off the bitter, sub-zero arctic air mass which has gripped northwest North America for more than a week, could be headed this way toward Thanksgiving.
-Tom Skilling
Gusty southwest winds will boost temperatures back into the mid 60s this afternoon and again Tuesday before a cold front moves through from the northwest Tuesday night. After a couple days under the influence of cool high pressure (but still above-average temperatures for this time of the year), computer models agree on a big warm-up this coming weekend with record highs in jeopardy both Saturday and Sunday. It is rare for Chicago to experience 70° temperatures in mid November, but once a pattern is established, it is hard to break it down. With the jet stream mean position flow west-to-east along and north of the U.S.-Canadian border, bitterly cold air is trapped in northern and central Canada, and only brief incursions of cool air are allowed to penetrate this far south. Warm air holds much more moisture, and converging winds produce strong uplift and instability, so cold frontal passages will trigger thunderstorms and the potential for severe weather.
Overnight showers and thunderstorms associated with a passing cold front will move east this morning. Indications were that welcome rainfall totals in the 0.25 to 0.75" range occurred with greatest amounts on the north side of the metro area. During the week ahead, the jet stream should hold a west-east flow over the Great Lakes and with only minor diversions south, cold air should continue to hold well north of the U.S.-Canadian border. As a result, temperatures this week are expected to see-saw from 5 to 10° above normal to as much as 20° above normal. Triggering these fluctuations will be cold fronts again Wednesday and this coming weekend. Southerly flow in advance of the fronts will pump temperatures well into the 60s midweek and again next weekend. The +100 m.p.h. jet stream will continue to direct a parade of fronts off the ocean into the pacific Northwest, resulting in heavy snows in the mountains and rain or a rain/snow mix in the valleys.
Although rainfall may be very spotty as Saturday gets under way, Chicago’s weather is predicted to deteriorate quickly this afternoon. Rain coverage increases from a few errant morning sprinkles and light showers over less than 20 percent of the area to heavier, wider-coverage rainfall likely to deliver a half an inch or more of rain in many locations before Sunday morning. If true, the storm would rank as fall 2005’s third heaviest rain-producer here to date. The rain comes in the wake of a second consecutive 70° high in November. Though cool air is to flirt with the metro area a day or two at a time over the coming week, the overall pattern is to remain mild over much of the Lower 48 east of the Rockies. Another 70° is possible as early as Tuesday. A high-altitude blocking pattern over eastern Russia—4,600 miles west of Chicago—is projected to hold into mid-November, locking this country’s mild westerly jet stream winds in place.
The area’s late season flirtation with 70° continues a second straight day Friday—only the 112th time in 135 years a November high temperature has been that warm. The predicted 70° high, a late-September-level reading, would be 17° above normal and only four degrees short of the 1978 record of 74°.
Thursday’s 70° at O’Hare was only the tenth reading at or above 70° on Nov. 3 since 1871 and the warmest reading for the date in 15 years—since a 70° high in 1990.
But as Chicagoan’s enjoyed Thursday’s warm southerly winds, wintry weather gripped the northern Plains and Rockies. Snow was reported 700 miles to Chicago’s northwest. In Montana, snow accumulated 5" in Jordan and 4" at Richey, while the 2.4" measured at Glasgow set a record for Nov. 3.
In Bettles, Alaska, which sits beneath 8" of snow, early-season Siberian air held Thursday’s high to -14° and the low to -29°.
Thursday’s predicted 72° high becomes the 157th day of 2005 with a temperature at or above 70°—the most here in 28 years. (Chicagoans enjoyed 158 days of 70° or higher in 1977). By comparison, a typical year produces 140 such readings at O’Hare and 144 at Midway—but only 113 occur along the lake front because of cooling lake breezes part of the year there.
Highs in the 70s are rare this late in the season. Only 110 of the 17,507 above 70° temperatures recorded here since 1871—that’s just six tenths of 1% of all our 70s—have occurred in November and only 83 beyond today’s date.
Thursday’s warmth arrives on gusty winds which have transported the unseasonable temperatures nearly 800 miles over the past 24 hours. Computer-generated wind trajectories indicate only late Wednesday, the warmth was over Mississippi and Arkansas.
Chicago appears headed into rare temperature territory Thursday—at least by November standards. Should a predicted high of 72° verify, it would mark only the 84th time the mercury here has passed 70° beyond Nov. 3 in 135 years of official weather records. Put a bit differently, fewer than one half of 1% of Chicago’s high temperatures this late in the season have been as warm.
Exceptionally strong westerly jet stream winds are whisking Pacific air across the country. The already mild air warms further as it sinks out of the Rockies and into the Plains, a process which induces compressional warming—raising its temperature.
The coming warmth is in marked contrast to the record chill recorded here in early November 1991. That early season cold spell produced six new temperature records and a string of eight consecutive days below 40°.
