September 2006 Archives

Temperatures will rise as a warm front approaches from the west today, a prelude to the first 80° temperatures experienced in the Chicago area since a high of 82° was recorded nearly two weeks ago on Sept. 17. In fact, if forecasts prove correct, 80° highs could be recorded 3 times this week—Monday, Tuesday and Saturday—just one short of the entire month of September’s total (4). Even with a midweek cool-down, highs are forecast to reach only into the 60s Wednesday and Thursday, temperatures are projected to average nearly 11° above normal for the next seven days. Though periodic showers or thunderstorms are in the forecast for the week ahead, it appears that Chicago will be positioned well south of the area of strongest frontal lift and available moisture. Oct.1-7 rainfall could well total less than a quarter inch here with one to two-inch totals possible across central Wisconsin and Lower Michigan.
-Paul Dailey, WGN-TV Meteorologist

Illinois State Climatologist Jim Angel reports that this September will go down as this state’s 22nd coolest since 1895, with statewide temperatures averaging some 2 degrees below normal. Chicago readings the last six days have been subnormal, and September temperatures will average nearly 1.5 degrees below the most recent 30-year norms. However, the warm front moving east through Illinois today will be followed by slowly strengthening southerly winds that will more than counterbalance the diminishing daylight and lower sun angle, ushering in a significant warm-up that will see highs warm into the 70s Sunday with July-like highs in the mid 80s projected Monday and Tuesday—temperature levels more than 15 degrees above early October normals. Actually, back-to-back 80s are not all that unusual. Chicago weather records at Midway Airport dating back to 1928 reveal 44 of the 78 Octobers (56 percent) have experienced consecutive 80°-plus days.
--By Paul Dailey, WGN Weather Center Meteorologist

September’s projected average temperature, 63.2º, comes in at 0.6º below the month’s climatological normal of 63.8º, noteworthy in that it ends a string of eight consecutive months during which Chicago’s (monthly) temperatures ran above normal. In addition, based upon preliminary temperature reports for the first 27 days of the month, September temperatures will average below normal across all of Illinois.
But don’t give up on summer just yet. In a weather pattern reversal characteristic of this time of the year, persistent northwesterly upper-level winds that have delivered several cool outbreaks in recent weeks are about to give way to southwesterlies. In response, Chicago’s temperatures will surge 45° from the middle 40s Saturday morning into the middle 80s Monday afternoon. A few showers and thunderstorms will accompany the warm-up, though they will be sporadic.
-Richard Koeneman -WGN-TV Meteorologist

The terrain of metropolitan Chicago ranges from sand dunes, forests and corn fields to the concrete canyons of the Loop—features that profoundly affect nighttime air temperatures when the sky is clear and winds are calm.
It’s not surprising, therefore, that the area’s overnight minimum temperatures display big variations. Similarly, when the air is calm, temperatures recorded at official “thermometer level,” about four feet above ground, usually run several degrees higher than readings right at the ground. Experience tells us that patchy frost can be expected when temperatures fall into the upper 30s.
The average date of the area’s first autumn frosts varies by nearly a month, from late October in downtown Chicago to early October in the chilliest outlying locations. This season’s first frost is right on schedule, happening early Friday morning in outlying rural locations.
-Richard Koeneman WGN-TV Meteorologist

Air of Canadian origin blasts across Chicagoland late today, initiating a temperature plunge that will culminate in a 28° drop by Thursday morning.
Air aloft will chill also, with readings a mile above the area hovering just above freezing through the day on Thursday, thereby establishing a vertical temperature differential sufficient to generate lake-effect rain showers. Borne along by brisk winds blowing from the north or northeast, those showers may dampen the area on Thursday. Were this early or mid winter, a similar situation would likely result in a significant lake-effect snow event.
It’s to be a short-lived cool spell. Winds, surface and aloft, turn westerly and then southwesterly by Saturday, and temperatures respond.
Area readings push toward 70º on Sunday, merely a prelude to a more vigorous warm surge on Monday that carries the city’s temperatures well into the 80s.
-Richard Koeneman WGN-TV Meteorologist

The atmosphere becomes more energetic and the weather becomes more vigorous in the autumn, and Chicago is about to experience some examples of that in upcoming days.
The autumn season, standing as it does between summer and winter, can on occasion deliver a little of the weather characteristic of both those seasons. The weather plate in upcoming days will offer Chicagoans varied servings of sunshine and summery warmth, blustery winds, autumnal chill, clouds and showers, a 33° temperature drop and a 45° temperature rise.
However, past autumns have delivered far larger fluctuations. Chicago’s temperatures plunged 57º from 84º on Oct. 31, 1950, to 27º four days later. In 1992, the city’s temperatures surged 55º from an early-morning low of 21º on Oct. 19 to 76º by the 23rd.
-Richard Koeneman, WGN-TV Meteorologist

The anniversaries of Chicago’s extreme weather events usually receive prominent publicity: Jan. 20, 1985 (-27º, the city’s lowest temperature); July 23, 1934 (109º, the city’s highest, though unofficial, temperature; Jan. 26-27, 1967 (23.0”, the city’s biggest snowstorm).
But today’s date, Sept. 25, has seemingly slipped through the cracks of the public consciousness even though it’s a significant date in Chicago’s weather history: Chicago officially logged its earliest-ever snow on this date in 1928 and also in 1942.
Although both snows were trace events (that is, they resulted in no accumulation), they created quite a public stir at the time. Sept. 25 in 1928 was a raw day, with high/low temperatures of 50°/39º; it was even worse in 1942: 46°/30º and 0.18” of rain in addition to the trace of snow.
This autumn may bring another early-snow event: Showers possibly accompanied by a few wet flakes might occur Friday.
--By Richard Koeneman, WGN Weather Center Meteorologist

Powered by torrential rains accompanying violent thunderstorms Friday evening and additional heavy showers on Saturday, rain totals accumulated since the first of September are climbing into record territory. At Chicago’s official weather observation site (O’Hare), month-to-date rainfall now stands at 5.76 inches, an amount that is 176 percent of the normal full-month total of 3.27 inches, and sufficient to make this the 14th wettest September since 1871, even if not another drop of rain falls through the remainder of the month.
Substantial as it is, this month’s rain total is not likely to challenge Chicago’s all-time September rainfall record: 14.17” logged in 1961. The remnants of Hurricane Carla delivered 5.21 inches of wind-driven rain Sep. 12-14, adding that total to other heavy rains in that record-wet month.
A cooperative weather observer in St. Charles logged 4.04” in t-storms Friday evening into Saturday afternoon.
-Richard Koeneman, WGN-TV Meteorologist

With a 140 m.p.h. jet stream directly overhead, a strong influx of warm, moist air from the Gulf of Mexico, and a warm front just to the west and south of Chicago, all the ingredients were set for a severe storm outbreak late Friday afternoon. Heavy downpours hit in eastern Kane, northern DuPage, and northern Cook counties. St. Charles and Mount Prospect reported over 3 inches of rain in an hour and a half. Those areas and many others reported flooded streets and paralyzed traffic. O’Hare’s 1.73 inch total far exceeded the previous record (1.09 inches in 1965) for Sept. 22. Aided by instability created by the diverging jet stream flow aloft on top of the converging winds at the warm frontal boundary below, towering storms built to 58,000 feet tall. Downdrafts resulted in widespread hail and wind damage (70 m.p.h. reported at Hanover Park and 60 m.p.h. near West Chicago). Funnel cloud reports and Doppler radar signatures prompted at least seven tornado warnings.
--By Paul Dailey, WGN Weather Center Meteorologist

Another powerful weather system, the latest and strongest in a series of August/September storms to sweep into the Midwest, is descending on Chicago today. Invigorated by an especially energetic jet stream that is blasting across the Midwest and huge temperature variations between the cold western and warm eastern halves of the storm system, the atmosphere is poised to bring potentially violent thunderstorms and locally heavy rainfall to Chicago and much of the Midwest.
Thunderstorms are “weather factories” capable of producing five dangerous phenomena: damaging winds, large hail, intense lightning, flood-producing rains and isolated tornadoes. The National Weather Service’s Storm Prediction Center advises that the greatest potential for severe conditions across northeast Illinois will extend from this afternoon into the overnight hours.
-Richard Koeneman-WGN-TV Meteorologist

It will come as no surprise to flood-weary residents of metropolitan Chicago that excessive rainfall has deluged the area since Aug. 1. Midway Airport’s climate statistician Frank Wachowski reports that 11.10 inches of rain has been logged there since that date—a total that is almost exactly twice the amount that history tells us would normally fall during that period. When added to all precipitation accumulated here since January 1, the year-to-date total climbs to an impressive 34.24 inches. That is 90 percent of Midway’s full-year total of 38.25 inches, and it ranks as the sixth greatest since 1928.
Yet another wet autumn storm has Chicago and the Midwest in its sight. After a sunny but chilly start this morning, increasing afternoon cloudiness heralds the approach of the latest weather system. Scattered showers work into the area late tonight, then become heavier and more numerous on Friday.
-Richard Koeneman WGN-TV Meteorologist

Tuesday’s chilly 55° high, a reading more typical of November than September and the coolest daytime temperature here in 4 months, failed by just 3° to reach the 52° record low maximum for the date set 68 years ago in 1938. Record readings are, by their very nature, rare. So challenging a record—as happened Tuesday—underscores the unusual nature of the chilly air mass still dominant as Wednesday dawns. At 55°, Tuesday was 18° below normal, more than 20° cooler than Sunday’s 82° and nearly 30° below the 84° high on Sept. 19 a year ago.
Early season chilly air has been a rare commodity here in the past decade. Five of the past ten Septembers haven’t even produced a sub-60° daytime high. In the past 66 years, the only two readings on a par with Tuesday’s 55° and which occurred as early or earlier were the 51° high on Sept. 17, 1981 and the 55° high on Sept. 15, 1993.
-Tom Skilling

Chicagoans find themselves in rare temperature territory Tuesday. The day’s November-level predicted high of 55° represents a 16° decline from Monday’s 71° and is more than 25° cooler than Sunday’s summerlike 82°. But even more impressive is the fact that only 265 of the 4,050 September high temps on the books here since 1871 have failed to warm above 59°. A high in the 50s Tuesday would mark only the 266th time that’s happened ranking it among the coolest 7% of September daytime highs on record in Chicago.
A second consecutive high In the 50s at Midway Airport Wednesday would establish still another cool weather benchmark for so early in the season. Dependent upon extensive cloudiness lingering, such a reading would mark the first time since May that back to back 50s have occurred and only the fourth time since 1928 that two or more highs in the 50s have been logged this early in the season.
-Tom Skilling

Temperatures flirted with 80º Saturday but soared into the lower and middle 80s on a very summery Sunday. The 85º high at Midway Airport was the warmest there in nearly a month, since an 87º high on Aug. 23. Far southern areas were even warmer with Pontiac reaching 88º and Kankakee hitting 90º. Buoyed by the heating, the humid atmosphere spawned towering thunderstorms during the late afternoon that brought brief but heavy downpours. At Midway rainfall totaled 0.70” with 0.50” of it falling in a 15-minute cloudburst. September rainfall there is now approaching 4” after an August total of 7.12”. However, rainfall here was trivial compared to the 5.50” deluge that brought flooding to Miller in extreme southwest Missouri.
Warm weather will not be a factor here the rest of the week as chilly air will lower Chicago area daytime highs into the 50s Tuesday and Wednesday as fall makes its first real impact statement of the season.
--By Steve Kahn, WGN Weather Center Meteorologist

Here are some pictures of Saturday night's beautiful sunset taken by some of our viewers. Thanks to everyone who shared their pictures with us. An explanation of what causes crepuscular rays is on the September 17 portion of the blog.

Photo taken by Alan Dawson Saturday night at the Hickory Hollow Campgrounds in Utica.

Photo taken by Jane Wills of Coal City, Ill.

Photo taken by Ann Wolf of Frankfort, Ill., who took this picture coming home from the Notre Dame vs. Michigan game

Photo in the Mokena area taken by Dawn Holstrom

This weekend’s summerlike highs around 80º will be distant memories by midweek as the season’s first real autumnal chill blasts into Chicago.
The initial phase of the cool-down will begin Sunday night amid a wave of potentially severe thunderstorms, lowering Monday’s highs into the upper 60s. The real core of the cool air will arrive Tuesday on what promises to a be cloudy and blustery day with light showers and the city’s first sub-60º high since mid-May. Though a modest temperature rebound into the 60s is likely by the end of the week, the autumnal feel will continue with clouds and frequent showers that will add to this month’s substantial rainfall totals.
Eastern Pacific Hurricane Lane made a 120 m.p.h. Category 3 landfall Saturday afternoon on Mexico’s Pacific coast north of Mazatlán. Now weakening, Lane’s remnants threaten flooding and mudslides as it moves north into Mexico’s interior.
-Steve Kahn WGN-TV Meteorologist

By this time last year, Chicagoans had enjoyed four times as many September 80s as the three on the books this month. The lack of 80s is unusual; only two Septembers in the past 40 years have logged fewer 80s by this date—1972 (with only one 80°-plus reading) and 1993 (with two).
The month has just passed its midpoint with an average temperature of 66.4°—a reading 7.3 degrees below the comparable period one year ago and chilly enough to rank 40th coolest of the 136 Sept. 1-15 periods on the books since 1871.
The predicted highs Saturday and Sunday mark the city’s warmest temps in eight days. But, the unfolding meteorological scenario in the Plains offers a clue on what’s ahead here. Grand Forks, N.D.’s record-breaking 86° Friday—16 degrees above normal—will be a distant memory there by Monday as highs fail to clear the 40s.
--By Tom Skilling, WGN-TV Chief Meteorologist

The strength of the newly declared El Niño in the Pacific may play an important role in this winter’s weather here. El Niños occur when easterly trade winds weaken over the Pacific Ocean west of South America and ocean temperatures warm. Global weather shifts are tied to the event over as much as 70% of the planet when El Niños occur.
Moderate and strong El Niños often boost winter temperatures, reducing snowfall here—sometimes dramatically—in 67% of the winters during which have occurred since 1950. But, the impact of weaker El Niños can be quite different. An analysis of those winters indicates 55%—including several in the barbarically cold late 1970s—have produced near or below normal temperatures and more snow. That’s why all eyes in the meteorological community will be on trends in the strength of the new El Niño in coming months.
-Tom Skilling

With soils across the area completely saturated after well over twice the normal amount rain in the August and September period—10.38” at Midway Airport versus the typical 4.79”—Wednesday’s thundery downpours translated quickly to run-off and serious flooding. Hardest hit was the city’s South Side and south suburban areas.
Midway Airport’s 1.08” brought that site’s September tally to 3.26”—just 0.19” below the normal rainfall which typically falls over the entire month of September. The past four days alone have generated 2.65”. Areas farther south were hit by the heaviest rains of all Wednesday. Morris in Grundy County was swamped by 4.81” while sections of Indiana’s Lake and Newton Counties were hit with over 5” of rain.
Chicago’s cloudy September continues. After another sunless day Wednesday, the month has seen just 45% of its possible sun—the least in 22 years.
-Tom Skilling

Just a year ago, Chicago’s high temperature surged to 94°, making it the fourth consecutive day with readings in the 90s. By comparison, Wednesday marks the fifth day the city’s been shrouded by clouds. September’s paltry 49% of its possible sunshine is well below the 62% considered normal. The month is on its way to becoming the fifth in a row with sub-normal sunshine.
With all the clouds, it’s little wonder September has averaged a stunning 7.5° cooler than the same period a year ago. Daytime highs the past four days alone have averaged just 68.1°—not only 6° below normal but cool enough to qualify as the chilliest Sept. 9-12 period in 13 years.
Thundery downpours hammered areas north of Chicago. Waukegan was hit by 1.42” while Kenosha was swamped by 2.09” and downtown Milwaukee recorded 2.30”. Over 300 lightning strokes were detected every 15 minutes Tuesday afternoon.
-Tom Skilling

The Chicago area was drenched for a fifth time in just six weeks Monday. Sunday’s sporadic rainfall turned heavy for hours Monday morning and rly afternoon—rain which was punctuated by lightning and thunder. Before the day had ended, 1.97” had accumulated at O’Hare, that site’s heaviest since 2.05” on July 20. The total was expected to increase overnight as new showers and thunderstorms, which flared near the Mississippi River late Monday then generated 65 m.p.h. gusts and hail south of Peoria near Havana, set their sights on the metro area.
Area rainfall was heaviest outside the city, topping 2” at Oak Brook, Woodridge, Mt. Prospect, Romeville and Clarendon Hills among others.
Midway Airport’s been hit with five 1”+ rains since August 1—nearly three times normal. That’s the greatest number of heavy rains in the period since six occurred in 1977.
-Tom Skilling

It was very fall-like across the Chicago area Sunday, damp, dark and dreary with intermittent rainfall that brought anywhere from a quarter to half an inch of rain to much of the area. But it was a different story downstate as temperatures surged into the middle and upper 80s under bright September sunshine. The large contrast in temperatures is helping fuel more rounds of showers and thunderstorms for Monday and Monday night that threaten to bring some very substantial rainfall totals to the Chicago area. The same system brought torrents of rain to northeast Iowa Sunday with nearly 1.5 inches at Dubuque and up to 3.5 inches just to the west along U.S. Highway 20. Similar totals could soak the Chicago area Monday.
Sunshine should finally return to this area by Wednesday as the weather pattern quickly reverts to a summer-like pattern. Highs should rebound into the 70s by midweek and grace the 80s by next weekend.
--By Steve Kahn, WGN Weather Center Meteorologist

The feel of autumn will definitely be in the air the next few days as Chicago, encased in gray, leaden skies is subjected to three consecutive sub-70º, damp, blustery and rainy days. By the time sunshine returns on Wednesday two inches or more of rain may have fallen as a series of weather disturbances pass to the south.
Despite the week’s dismal start, summery weather is set to make a decisive return late in the week, as southwest winds boost temperatures back into the 80s.
Typical of weather during the fall transition season, the next cool snap is already in sight by late next weekend.
In the Atlantic, Tropical Storm Florence is expected to become the season’s second hurricane Sunday as it churns northwest on a path that should take it near Bermuda by Monday morning. Last year at this time eight hurricanes were already on the books.
-Steve Kahn WGN-TV Meteorologist

Not since early June has a cooler weekend greeted Chicagoans. It’s a huge change from Friday’s summerlike highs, which included 83° at O’Hare and Midway, and the 88° peak reading far south at Kankakee. For many parts of the metro area, it was the warmest weather in 2 weeks.
A sprawling Canadian high with meteorological autumn’s coolest air yet sits draped across virtually the entire northeast quarter of North America as Saturday dawns. It’s responsible for slashing daytime temperatures more than 30 degrees at Bayfield, Wis., from 85° Thursday to 53° Friday. Local residents report the earliest autumn color change there in years.
Powerful thunderstorms at the periphery of the incoming chill bombarded sections of northern Iowa and southern Wisconsin overnight with hail up to 1” in diameter. In Michigan, powerful storm gusts downed trees in Kent and Ottawa counties—an area which includes Grand Rapids.
--Tom Skilling, WGN-TV Chief Meteorologist

Pilot Anson Mount snapped this picture of the nearly full moon from Waukegan Airport around 8 p.m. Friday evening. The full moon took place two days ago on Sept. 7. Anson reported lightning associated with strong Wisconsin thunderstorms visible to the north. By the way, the area's next full moon occurs Oct. 6 and is the Harvest Moon.
--Tom Skilling, WGN-TV Chief Meteorologist

Temperatures soared to 90° at Grand Forks and Bismarck, N.D., Thursday, but will struggle just to make the 50s in those cities this weekend. That’s significant because steering winds are guiding the same unseasonably warm air which pushed North Dakota readings 15° above normal into the Chicago area. Friday’s predicted high of 87° is to be this area’s warmest in 16 days.
Warm air—even when it’s very warm— isn’t quite as stifling this time of year. With days more than two hours shorter than June 21 (our longest day), the sun a bit closer to the horizon and less directly overhead, and sunlight intensities down 30% from two and half months earlier, warm readings feel less intense than they might have back in June.
This year’s monsoon rains in the Southwest have been the heaviest in 16 years. Chicagoans may be surprised to hear Tucson has recorded 9.83” since June —more than Chicago’s 9.58”
-Tom Skilling

Bret of Manteno, Illinois forwarded us this photograph of Tuesday afternoon's (around 2:15 P.M.) cold air funnel just east of I-57 one mile northwest of Peotone. He and is family watched the funnel several minutes before grabbing his camera and snapping these shots.
-Tom Skilling

PHOTO COURTESY: Bret of Manteno

The storms which swept sections of the Chicago metro area this past Monday (9/4/2006) produced this wall cloud over DeKalb County. Frank Christiansen was the photographer and included the following description:

"With the heavy downpours that came out of Monday's storm, I thought you might be interested in this. My wife and I were out for a drive and keeping an eye on the developing eastbound storm maybe 5 miles west of DeKalb. As it developed, it became this wall cloud structure on the far west side of DeKalb just west of the stadium. It wasn't quite as defined and precise as the traditional "perfect" wall cloud and there was no circulation, but it still was a "watcher"."

Thanks for the great shot, Frank!

Tom Skilling, WGN-TV Chief Meteorologist

PHOTO COURTESY: Frank Christiansen

Thanks to Jim Zandonai for this revealing shot of a Rockford golf course under water in the wake of Monday afternoon/evening's cloudburst which submerged southeast sections of that city under flood waters. Some long time area residents are calling the flooding the worst they've seen in recent memory.

PHOTO COURTESY: Jim Zandonai

Temperatures surge above 80° a second day Thursday and could move to within striking distance of 90° Friday afternoon when an 88° high is predicted. Chicago’s last 90°+ temperature was the blistering 97° high recorded on Aug. 2. Weather records reveal that while a majority of the city’s 80s have occurred by this date, 12% of Chicago’s annual 80s occur between now and Nov. 1.
A bit of compressional warming Friday afternoon is behind expectations of unseasonable upper 80° highs—readings 12° warmer than normal for the date. As southwest winds ahead of an incoming cold front converge with the northeast winds behind it, the convergence process compresses/warms the air.
Isolated thunderstorms may flare in the area with daytime heating Thursday afternoon. The handful of t-storms which bubbled into existence Wednesday along a lake breeze front produced 1” hail west of Milwaukee in Waukesha County.
-Tom Skilling

This cold air funnel was photographed by Bill Schreiber Tuesday afternoon (9/5/2006) north of the Peotone Fire Station on Joliet Road.

PHOTO COURTESY: Bill Schreiber

Our thanks to Dianna Massat for sharing this shot of one of Tuesday's south suburban cold air funnels photographed around 2:30 P.M. just south of Monee.
-Tom Skilling, Chief Meteorologist, WGN-TV

PHOTO COURTESY: Dianna J. Massat

The scope of the destruction brought about by Monday afternoon and evening's 6.51" rain on Rockford's southeast side is all too apparent in these revealing photographs shot by Sara Kallenbach. Sara tells us she still finds it hard to believe the area was flooded in such a devastating manner in such a shot period of time. The deluge was the product of thunderstorms training (flaring repeatedly) over the same area. Our thanks to Sara for her remarkable photographic record of the Labor Day, 2006 cloudburst.

Our thanks to Mark Henderson, Chief Meteorologist at WIFR-TV in Rockford and former intern in our WGN-TV weather office for his assistance in covering the unfolding situation and its aftermath.
-Tom Skilling, WGN-TV Chief Meteorologist

PHOTO COURTESY: Sara Kallenbach

Flood waters, still eight feet deep in basements hardest hit by southeast Rockford’s Labor Day cloudburst, continued receeding Tuesday. A rain measurement from one National Weather Service COOP observer put the downpour at 6.51”—nearly 190% of the 3.47” which falls in an entire month there. Many long time Rockford residents characterized Monday afternoon and evening’s flooding as that city’s worst in nearly 30 years.
It was cold air funnels, not torrential downpours, that caught the attention of south suburban residents Tuesday. The same cold upper storm behind Monday’s flooding rains in Rockford produced huge vertical temperature declines which fostered development of Tuesday’s funnel-bearing t-storms observed across Will and Kankakee counties. Ground level temperatures of 77° contrasted with cloud top readings of -58°—encouraging air to rise and funnels to form.
-Tom Skilling

Cold air funnels develop Tuesday in the chilly pool of air above Matteson, Illinois and the Chicago metro area

These cold air funnels developed over Matteson, Illinois and were photographed by Michelle Dural. The same cold pool of air within an upper atmospheric storm system behind Monday's powerful storms which flooded Rockford, is at work assisting the development of these funnels. The cold air aloft in such a system increases the rate at which temperatures decline with altitude, encouraging air to rise more vigorously than it otherwise might. When one of these updrafts is stronger than is the area surrounding, air much rush in from the periphery of the column of rising air which produces the swirl and the resulting funnel cloud. Cold air funnels can touchdown--but not always. And, they tend not to possess the devastating winds which accompany conventional tornadoes produced by supercell thunderstorms.
-Tom Skilling, WGN-TV Chief Meteorologist

PHOTO COURTESY: Michelle Dural

At least one of the cloudburst-generating thunderstorms, which fired repeatedly Monday (Labor Day) afternoon and early evening over the Rockford area, produced this double rainbow which, according to Theodore Juern, who shares these photos with us, had drivers on I-90 pulling to the side of the highway to observe and photograph. The storm produced some of the most severe flooding observed in recent memory over the southeast quadrant of Rockford with rainfalls estimated at 6".
-Tom Skilling, WGN-TV Chief meteorologist

PHOTO COURTESY: Theodore Juern

Serious flooding hit Rockford’s southeast side Monday afternoon turning Labor Day into a nightmare for many. Stranded motorists and residents had to be evacuated by boat—rescues still underway late Monday evening. Long-time residents, including 28-year Rockford resident Bob Ellison characterized the flooding as the worst he’d seen in all his years there. Flood waters, which first submerged sections of the city’s east side mid-afternoon expanded westward, engulfing homes and businesses over a swath of the city estimated as much as five miles in length and four to five blocks wide. Hours of thunderstorms, which became heavy around 3 p.m., reduced visibilities to fractions of a mile while producing wind gusts as high as 30 m.p.h. Hail, in some instances the size of golf balls, bombarded surrounding areas, covering the ground at some locations. Vehicles were submerged up to window-level, and basement windows were reported blown out by the force of the flood water.
--Tom Skilling, WGN-TV Chief Meteorologist

As a slow-moving low pressure system moves through northern and central Illinois today and Tuesday, Northeast Illinois is in store for an extended period of clouds, showers and thunderstorms. Highs will run some 8 to 10 degrees below normal. While torrential rains such as the 2.54 inches observed in Mason City, Iowa, on Saturday and the 1-inch hail that covered the ground 4 inches deep in Danbury (northwest Iowa) Sunday afternoon associated with this same weather system will probably not be observed, two-day rainfall totals in excess of an inch may be commonplace over the metro area, and the extensive column of cold air aloft could produce half-to-1-inch hail in spots.
Heavy rains triggered by the weakening Tropical Storm John continued to deluge central Baja California and northwestern Mexico Sunday with attendant moisture streaming north, prompting flash flood watches for the mountains and deserts of southern California today.
--Paul Dailey, WGN Weather Center Meteorologist

During the next 24 hours, clouds are expected to slowly increase and thicken in advance of a slow-moving low pressure system approaching from the west. With the low meandering through northern Illinois Monday and Tuesday, associated clouds, showers and thunderstorms, along with easterly winds will keep temperatures in a very narrow 10° range.
Readings may hover in the 60s for the better part of a 48 to 72-hour period. Should temperatures reach 70° Monday and Tuesday, there is a good chance highs will stay in the 70s the rest of the week. This would give Chicago a record-breaking string of 15 days with 70° highs dating back to Aug. 26.
As Tropical Storm “John” is forecast to weaken and move out to sea leaving the Baja coast behind, the remnant of “Ernesto” dies out over New England. However, the east coast will be threatened anew by heavy rains during the week ahead.
-Paul Dailey, WGN-TV Meteorologist

There’s a hint of autumn in the air as this Labor Day holiday weekend gets underway. Chicagoans haven’t experienced a weekend with temperatures on par with those predicted over the next few days in nearly three months. Daytime highs Saturday and Sunday are predicted to hold to the mid 70s—levels more typical of mid or late September.
Despite the cool “feel” of the air in recent days, Chicago weather records hint strongly that warm weather isn’t behind us yet. An average of 14 more days of 80° or warmer temperatures—and even two days of 90°-plus readings—have typically occurred from this date forward.
The Mid-Atlantic was pounded by Tropical Storm Ernesto’s high winds and torrential rains Friday. Rainfall amounted to 11.92” at Surf City, N.C., while Virginia Beach, Va., was awash after 10.43”. Coastal wind gusts clocked as high as 74 m.p.h. produced waves more than 17 feet high offshore.
--By Tom Skilling, WGN-TV Chief Meteorologist