August 2007 Archives

With only hours to run in the June through August meteorological summer season, the area is in the midst of a dry spell destined to become Chicago’s longest in a month. No rain is predicted here until spotty t-storms threaten far northern sections of the metro area late Labor Day (Monday). Up to now, the longest rain-free period in the past month was the 7 day stretch from July 28-Aug. 3.
The frequency with which rain has fallen in the past three months has been impressive. The summer’s 15.85” official tally at O’Hare ranks 9th wettest of the past 137 years and accumulated in rains which fell measurably on 43 days—far beyond the 29 days considered “normal.” Thunderstorms occurred on 26 summer days—more than the usual 15.
September opens Saturday with 2 hours less daylight than back on June 21, the start of summer and the northern hemisphere’s longest day.
--By Tom Skilling, WGN-TV Chief Meteorologist

There have been two cooler daytime highs this month—68° on August 18 and 19. But, neither reading occurred amid the abundance of sunshine predicted Thursday. That highs will struggle to make it to 73° today is a sign that seasonal cooling is underway and occasionally strong enough to make it all the way into Chicago. The cooling will accelerate over the coming month. While week to week daytime temperature declines here in August’s closing week average 1°, the rate at which readings pull back will increase to more than 3° per week by late September.
Warm weather enthusiasts shouldn’t be discouraged yet. Daytime highs return to the 80s for the Labor Day weekend. Weather history indicates an average of three of the 24 daytime highs at or above 90°occur beyond this date.
Phoenix, Arizona broiled at 113° Wednesday, the 29th day this year over 110°—a new record!

--By Tom Skilling, WGN-TV Chief Meteorologist

David Lindgren, whose reports of rainfall from the University of Illinois Research Farm in DeKalb County (7 miles SSW of the city of DeKalb) over the the past week’s storms and thundery deluges have been outstanding and very useful, sends us these pictures of the Rock River at the dam in Dixon, Illinois. David tells us the pictures don’t do the situation there justice since they are unable to communicate the roar of the river. Rainfall over the June, July and August meteorological summer period at the
DeKalb County farm site has been the heaviest in 126 years of observations totaling a remarkable 26.47” , a total which David reports is even heavier than 1987”s 23.07”.

Our thanks to David for continue to supply us with the great reports and for these photos!

Tom Skilling

Photo courtesy: David Lindgren

Chicago’s 17th official 90° temperature of the year is on the books. Tuesday’s 91° high at O’Hare was August’s sixth 90°+ high and the city’s warmest temperature in three weeks. Other metro area thermometer readings Tuesday included 93° at Northerly Island and 95° at Gary, which was the metro area’s hot spot. In combination with the day’s muggy 70°+ Gulf Coast-level dewpoints, heat indexes at the two sites topped out at 104° and 105° respectively.
The heat provoked waves of powerful thunderstorms, which at one point, stretched from Kansas to Upper Michigan—some 60,000 ft. tall and accompanied by 80 mph wind gusts. At Crandon, WI (in upstate Forest County), t-storm winds downed trees and flipped a mobile home. Preliminary reports indicate the massive squall line may have spawned at least six twisters—four in Iowa and one in Nebraska.
-By Tom Skilling, WGN-TV Chief Meteorologist

Stormchaser Chad Cowan has shared his photos and accounts of storm encounters with us on this blog before. But, THE series of photos we post here hits home because they include hometown scenes in which the sheer power of last Thursday's thunderstorms is front and center. Chad shares some of his thoughts here in this excerpt of a write-up he did for StormTrack:

""I ducked out of work a little early and tried to get up to the 96th floor of the Hancock Tower to watch the squall move in, but the storm beat me there and I was caught on the street. I saw a woman get knocked off her feet by the gusts and a few large branches snap off. My commute home took 3x longer than usual due to trees on the train tracks and power outages.
The cemetery in which I took the damage photos is about 4 miles north of downtown, near the Sheridan red line stop (4000 block of N Sheridan), for anyone familiar with the area. As you can see in my pictures, the trees that were blown over or snapped are amazingly large. I was surprised to see some of the large trees were snapped in half, rather than blown over. "

Chad Cowan's photography and his always riveting analyses of the storm situations he encounters are alway A-1! Thanks Chad!

Tom Skilling

Photo courtesy: Chad Cowan

These storm clouds over West Yellowstone, Mountain, were photographed and forwarded to us us by Larry Jahn, who took them during a driving vacation to Seattle. Larry tells us they ended up producing only a little rain shortly after he took the pictures. He adds: “We escaped all the heat on the entire trip to the high country and didn't miss the heat/humidity of Illinois at all!!” Sounds like a great getaway! Thanks for these amazing photos, Larry!

Tom Skilling

Photo courtesy: Larry Jahn

Samuel Shea, service climatologist at the Midwestern Regional Climate Center in Champaign, shares this amazing collage of images from this morning's lunar eclipse. In his e-mail to me, Sam tells us:

"...the weather could not have been any more perfect here. The images were captured in the lawn of the Illinois State Water Survey/Midwestern Regional Climate Center."

Sam tells us he has other pictures online from various times during the eclipse if you click on this link:

http://picasaweb.google.com/samuel.shea/LunarEclipse20070828


Thanks SO MUCH for sharing these with us, Sam, and please pass along our best wishes to all of your colleagues at the Illinois State Water Survey and the Midwestern Regional Climate Center!

Tom Skilling

Photo courtesy: Samuel Shea

The Chicago area flirts with 90 degrees Tuesday for the first time in a week and only the sixth time this month. By almost every measure, meteorological summer 2007 has been a warm one. With just 4 days left in August and the meteorological summer season set to close at midnight this Friday, readings are running 1.7 degrees above normal, daily temperature averages have finished above normal 53 of the past 87 days (61% of the time) and overall air conditioning usage is estimated to have increased nearly 20%. Yet, despite all these warm weather indicators, the number of days at or above 90 degrees is actually off long term averages by 20%. A 91 degree high today marks the 17th 90 degree+ day this year—20 is considered normal.
At 3:30 p.m. on this date 17 years ago, the most powerful U.S. tornado to occur in August formed near Oswego and began a deadly 16.4 mile rampage through Crest Hill and Plainfield. By the time it had dissipated, 29 people were dead and more than 300 injured.
--By Tom Skilling, WGN-TV Chief Meteorologist

Nguyen-Anh Le shares this spectacular photo he took of lightning as viewed from Chicago's Loop. Many thanks for sharing this with us Nguyen-Anh!

Tom Skilling

Photo courtesy: Nguyen-Anh

Eric A. Richeke of Griffith, Indiana sends relays these photos of serious flooding in and around the Griffith area of northwest Indiana—a region hit more than once in recent weeks by deluge-generating storms. Thanks Eric!

Tom Skilling

Photo courtesy: Eric A. Richeke

Jay Kleeman has sent us these shots. In his e-mail to us, he writes:

“The scope of the damage cannot be described. Some folks have BIG holes in their houses and impassable driveways front doors.”

Thanks Jay!

Tom Skilling

Photo courtesy: Jay Kleeman

Photos of late last week’s storms and flooding rains continue to come into our weather office and we want to share as many as I can with you. From the hard-hit Geneva, Illinois-area in the Fox Valley, Mike Anderson shares these amazing shots with us. They certainly help visually tell the story of one of this area’s most expansive storm outbreaks in decades. Thanks Mike!

Tom Skilling

Photo courtesy: Mike Anderson

The Streamwood area didn’t escape this past week’s storms. Joey Pudlik e-mailed these images to us from Streamwood, explaining:

“I just wanted to let you know about the storms that moved through on Thursday. I live out in Streamwood and I estimated the winds to be possibly in excess of 80MPH. There were several 2 foot diameter trees and tree limbs down, some were smaller. Several of the trees and tree limbs fell on cars, houses, power poles and power lines. I just got my power back at 3AM Saturday morning, it was out for a day and a half. We also had to deal with extreme flooding which put some roads under 3 feet of water and made the Poplar Creek rise to an all time high, the creek came within 25 yard of houses.”

Thanks for sharing your photos with us, Joey!

Tom Skilling

Photo courtesy: Joey Pudlik

The city can expect two more rain-free days to clean up and dry out before the next round of precipitation threatens here Tuesday night and Wednesday. With only light to moderate rainfall expected, this August should end as Chicago's fourth wettest since records began in 1871. Not so at South Bend, Ind., where the month's 8.88" is the most in any August, while Rockford's 13.82" total elevates this August to the all-time wettest of any month there.
With clear skies expected Monday night, early rising Chicagoans with a view to the west will be able to see the first half of a total lunar eclipse. The full moon will gradually disappear as it moves into the Earth's shadow with the eclipse reaching totality at 4:52 a.m. Unfortunately, Chicagoans will miss the moon's emergence from totality, which according to Dan Joyce, astronomer at Triton College's Cernan Earth and Space Center, will not be visible here, a result of moonset and the onset of twilight.
--By Steve Kahn, WGN Weather Center Meteorologist

The great rains of August 2007 have ended, at least for a few days. After three weeks of downpours that brought widespread flooding and historic monthly totals to many areas, nature’s rain machine is shutting down here for a while. Drier air will be making inroads into the area giving a chance for the thoroughly soaked ground to dry out and flood-swollen area rivers to recede.
However, the book on August precipitation is not yet complete. With O’Hare’s August rainfall total at a robust 9.70” and many other locales tallying more than a foot of rain, monthly totals are still likely climb as the month’s final round of precipitation is expected to arrive Tuesday night and Wednesday.
The hurricane season is approaching its most active period. Though the tropics remain quiet in the wake of Hurricane Dean, the latest forecasts still call for a very active season and new tropical cyclone development could quickly initiate.

--By Steve Kahn, WGN Weather Center Meteorologist

After a run of tumultuous weather this week, Illinois state climatologist Dr. Jim Angel has confirmed what many flood and storm-plagued northern Illinoisans suspect. August rainfalls averaged across all of northeast Illinois, many in excess of 12" and well beyond the 4.62" considered normal in Chicago, are the heaviest since regional records began in 1895. An average of 11.32" has fallen in an area from Boone to LaSalle County eastward -- including the Chicago metro area. That total surpasses the previous record of 11.02" set in August of 1987.
Individual weather station totals run as high as 16" at southern McHenry County's Huntley, 15.05" at Elgin and 14.19" in rural DeKalb County. Chicago's 9.36" in August at O'Hare Airport is the 2nd wettest of the past 137 years.
The month's tally of thunderstorm days -- 14 -- equals the record for the most August thunderstorm days set back in 1940.
--By Tom Skilling, WGN-TV Chief Meteorologist

These storm photos are of a huge tree uprooted on May Street that landed on this car in Elmhurst. Photos courtesy of Michael White. Elmhurst was another community hit hard by the storms. Many residents there are still without power as of 7 p.m. Friday. Thanks for the photos, Mike.
--By Bill Snyder, WGN-TV Weather Producer

Photos courtesy of Michael White

Jim Marocchi, who sent us these pictures from the Winfield area, tells us he was out riding his bike when he spotted the approaching storms. At that point, "I saw the front part of the line, the wall cloud, with what looked like some rotation, or at least dropping cloud structure on the front side of the wall cloud. I didn't take a picture of that, but did capture these other pics. I was too concerned about getting home before getting swept aside by the gust front. Lots of damage in and around the Winfield area." Thanks for the great photos, Jim! Glad you made it home!
--By Tom Skilling, WGN-TV Chief Meteorologist

Photos courtesy of Jim Marocchi

Photographer David Mayhew, whose work always amazes us, was busy again Thursday as storms hammered the city and put on another spectacular lightning display. For hours Thursday afternoon and evening, the deluge-generating thunderstorms generated more the 3,400 cloud-to-ground lightning strikes over ten-minute periods. Thanks for sharing these incredible photos with us, David!
--By Tom Skilling, WGN-TV Chief Meteorologist

Photos courtesy of David Mayhew Photography

Mike Frankowski shares this remarkable photograph taken in South Elgin around 1:30 am Friday morning. Great shot, Mike!
--By Tom Skilling, WGN-TV Chief Meteorologist

Photo courtesy of Mike Frankowski

Tracey Surface captures airborne debris swirling within Thursday's 70 m.p.h.-plus gust-generating thunderstorms. Her perspective is an interesting one -- looking west from the 22nd floor window as the the storms rolled in...
--By Tom Skilling, WGN-TV Chief Meteorologist

Photo courtesy of Tracey Surface

Brian Bessler captured the storms sweeping into DeKalb Thursday--and the sun which tried to shine afterward. Thanks Brian!
--By Tom Skilling, WGN-TV Chief Meteorologist

Photos courtesy of Brian Bessler

Few sections of the Chicago metro area have been hit any harder by recent storms than DeKalb. Northern Illinois University's Dr. Dave Changnon reports classes cancelled today in the wake of Thursday's fierce storms and the recent rash of downpours which have produced horrendous flood problems shown here. Our thanks to Suzy Changnon for these remarkable photos from the DeKalb area. Here's a portion of the e-mail from Suzy:

"Here are some photos our family took as we toured flood-ravaged DeKalb
this morning. Both public golf courses are flooded. The first five photos are of the Kishwaukee River, near the WNIU/WNIJ studios on First Street. The last photo shows water flowing over the Lucinda Avenue bridge on the NIU campus. The campus closed at mid morning due to lots of basement flooding and other facilities difficulties."

Thanks to both Dave and Suzy for the timely updates--and stay dry!

--By Tom Skilling, WGN-TV Chief Meteorologist

Photos Courtesy of Dave and Judy Changnon

Daniel Casper shares these photos of Thursday's storms sweeping into south-suburban Manhattan, Illinois. Many thanks, Dan!
--By Tom Skilling, WGN-TV Chief Meteorologist

Photos courtesy of Daniel Casper, Midwest Video Productions, Manhattan, Illinois

So far August, 2007 has brought an unprecedented 13.25" of rain to my Arlington Heights rain gauge. Yesterday's storms were as prolonged and intense as any that I can remember. The neighborhood is littered with large branches and limbs after winds of 70+ m.p.h. roared through yesterday afternoon. Standing water is everywhere and retention basins are brim-full after the unrelenting downpours.

As Tom Skilling mentioned last night on his TV weathercast and also on this morning's Tribune weather page, the severity of yesterday's storms in terms of the vast expanse of the metropolitan area that was affected is one of the greatest in memory.

The scope of the damage brought back memories of a derecho that swept the Chicago area in similar fashion 42 years ago across the midnight hours of August 26-27, 1965, but that storm was a "hit-and-run" job and not part of a week-long siege of deluges like the region is currently experiencing.

That memorable storm will be revisited as the subject of the main feature on Monday August 27th's Tribune weather page and on this blog .

Partially submerged bench on Monday August 20 when monthly rainfall stood at 10"+
Photo by Steve Kahn

Same bench on Friday August 24 with monthly rainfall now at 13.25".
Photo by Steve Kahn

Snowy egret surveys the flooded Lake Arlington shoreline
Photo by Steve Kahn

The Chicago area is no stranger to powerful thunderstorms. But the expanse and breadth of Thursday afternoon and evening’s outbreak was enough to make even veteran meteorologists, like my colleague Steve Kahn, who for more than 40 years worked for the National Weather Service here, sit up and take notice. Rare is the storm outbreak that produces damage and flooding from one corner of the metro area to the other. Yet, that’s just what happened yesterday. Steve compares the scope of the damage produced by Thursday’s storms to an Aug. 26-27, 1965 squall line which, unlike the latest surge, hit in the middle of the night. The area’s strongest wind gusts reached 80 m.p.h. at Manhattan and 75 m.p.h. at Elgin. But 60+ m.p.h. wind gusts swept virtually every corner of the region. The storms roared across the area at nearly 60 m.p.h. and towered at one point to 64,000 ft.—more than 12 miles into the atmosphere.

--By Tom Skilling, WGN-TV Chief Meteorologist

Thanks to Mark and Jaimi Vortruba for these shots of Thursday's storm damage in Chicago's Lakeview neighborhood.

Photo courtesy: Mark and Jaimi Votruba

John Lykowski, who sends us this revealing shot taken after Thursday's
storm hit around 3:30 pm, reports:

"A parked Oldsmobile on Henley St. in Glenview, IL. was the unfortunate
victim of a large branch which broke off a tree during the storm and
crushed the upper part of the roof and window."

Thanks for the report and photo, John

Tom Skilling

Photo courtesy of John Lykowski

John Denk for this Tinley Park offers us this perspective on Thursday afternoon's incoming storms. Thanks John!

Tom Skilling

Photo courtesy: John Denk

Storms, which for a time, forced evacuation of the control tower at O'Hare International and halted all flight operations there, lambasted the Chicago area. The power has flickered much of the afternoon here at WGN as we've moved to back-up power.

Terri Bradley of Buffalo Grove shares these photos of this afternoon's squall line as it roared into the area at nearly 50 m.p.h. At one point or another this afternoon, tornado warnings were in effect for portions of DeKalb, Boone, Kane, DuPage, Cook and Will Counties Damage reports have been numerous and it's going to take some time to get a read on the full extent of the damage. We're told many trees are down across the Fox Valley, where power failed for a time---including trees which fell on buildings and took down power lines down in the west suburban Geneva in the Fox Valley. There, WeatherBug sensors indicate 60+ m.p.h. gusts.

Damage has been reported in Mt. Prospect and 70 m.p.h. winds have been clocked by my meteorological colleague Steve Kahn in Arlington Heights. Windows were reportedly blown out of the Chicago Historical Society at Fullerton and Lake Shore Drive and a building has reportedly been heavily damaged if not demolished by the storm's fury near Belmont and Western with emergency vehicles on the scene as of this posting (at 5 p.m.). We've received numerous reports of funnel clouds and an unconfirmed tornado was reported in the Bolingbrook area. Gusts of 70 m.p.h. hit Wheaton, Streamwood and Glenview--and 80 m.p.h. gusts reported by the National Weather Service in the Will County community of Manhattan.

The dramatic wall cloud photos we've posted with this text were taken by George Isaacs 1/4 mile south of his home in far west suburban Elburn around 2:57 p.m.
This afternoon's storms emanated from huge thunderstorms with tops scanned to 55,000 ft.
Importantly, the flood threat hasn't passed. Downpours accompanied Thursday afternoon storms and new storm clusters threaten overnight, Friday and Friday night--any one of which could also produce severe weather. All of northern Illinois continues under a Flash Flood Watch through late Friday night. A severe t-storm watch continues until 8 p.m.

Tom Skilling
Chief Meteorologist, WGN-TV

Photo courtesy: Terry Bradley

Photo courtesy: George Isaacs

Wednesday’s evening’s powerful thunderstorms brought 1-2” rains and gusts to 40 m.p.h. to sections of the metro area. We noted as many as 4,500 cloud to ground strikes from our lightning detection data over a whole series of ten minute periods from thunderstorms which towered as high as 68,000 ft. on occasion. David Mayhew, whose remarkable photographic work we’ve featured on this page before, shares these images of last night’s lightning with us as the storms swept across Chicago. Many thanks David!!

Tom Skilling



Photos courtesy: David Mayhew

A second wave of powerful t-storms erupted late Wednesday battering sections of the area with 60 m.p.h. winds while unloading as much as 1.60” of rain near SW suburban Marseilles. Waves of storms to Chicago’s north in recent days have left La Crosse and Madison, Wisc. reeling with 12.23” and 13.33” August rain tallies—amounts which have exceeded all previous August records and now stand as new all-time monthly precipitation highs.
Wednesday evening’s storms, which generated dazzling cloud to ground lightning—4,500 cloud to ground strokes within a 200 mile radius of Chicago in just ten minutes—followed Chicago’s first 90° high in 15 days.
Predawn t-storms Wednesday sent 50 m.p.h. winds roaring across the area and out over Lake Michigan. The waves generated there were reflected from Michigan/Indiana back to Chicago’s shoreline, giving rise to a series of minor seiches (lake-level fluctuations.
--By Tom Skilling, WGN-TV Chief Meteorologist

Dan Strickland, on vacation with his family (which includes our own Jackie Bang) in Green Lake, Wisconsin, photographed this spectacular cloud to ground lightning discharge around 2 a.m. Wednesday morning. The powerful storms, which appeared as a fast moving bow-shaped line on radar displays--the signature for strong and potentially damaging winds, swept across southern Wisconsin and northern Illinois generating powerful wind gusts, driving downpours and stunning lightning displays, as pictured here. Once out over Lake Michigan, the squall line appears to have generated a "seiche" activity--rapid lake level fluctuations--- Wednesday morning along Chicago's lakefront--notably near Montrose Harbor. One of our viewers reported the 6" of water she had waded into while walking her dog suddenly disappeared only to return shortly afterward--the sort of oscillation in lake levels typical with seiches. The strong winds which gush out of a line of storms like those which swept the area this morning, produce waves on the lake which hit the Michigan/Indiana shoreline and reflect back to the Illinois side of the lake as a seiche.
Thanks to Dan Strictland for the stunning photo--and have a great vacation!!

-Tom Skilling


Photo courtesy of Dan Strickland

My friend and meteorological colleague Mike Stone of WTOL-TV forwards these photographs of the serious flooding which has swept northern Ohio in the past week. Mike writes:

“Areas south of Toledo near Findlay, Bucyrus and Mansfield have picked up a ton of rain. Some spots had 3-6"+ of rain Sun-Tue, and saw another 1-4"+ Tuesday night into Wednesday morning. Isolated areas picked up 12"+. Storms this morning trained over the already flooded areas. The Blanchard River in Findlay may reach a historic high. Currently at 18.24', forecasted to hit the record stage of 18.5'.—the flood stage is 11'.”

Thanks Mike for sharing these photos with us!

Tom Skilling

Photo courtesy: Mike Stone

Linda Eck shares these views of downed trees Thursday afternoon and evening near 6300 W. Huntington Street in Chicago. Thanks for these shots, Linda!

Tom Skilling

Photo courtesy: Linda Eck

Thunderstorms, among this summer’s most powerful to date, lambasted sections of South Dakota, Nebraska and Iowa overnight late Tuesday. Reports of mammoth 6-8” diameter hailstones near Dante, S.D., which if verified would rival the all-time record 7” diameter hail which punched holes in roofs in Aurora, Neb. on June 22, 2003, underscored the remarkable intensity of Tuesday’s storm outbreak. With cloud tops which mushroomed to 72,000 ft., reports of 80 m.p.h. gusts near Rolfe and 4.50” of rain at Meridan—both in northwest Iowa—came as no surprise.
The eastbound storms threatened to push the record August rain tallies at LaCrosse, Wisc. (11.95”) and Madison (10.49”) to all-time monthly totals. Ironically, while these cities have never tallied bigger monthly totals, Duluth, Minn.—only several hundred miles to the north—has recorded only 0.24” this month, its driest August ever.

--By Tom Skilling, WGN-TV Chief Meteorologist

Our thanks to Eugene Winter of Des Plaines who was kind enough to send us this picture of the current flooding on the Des Plaines River. Eugene's question about another Des Plaines River flood event back in September, 1986 was answered in today's Ask Tom Why column.

Photo by Eugene Winter

With soils saturated and a number of streams and rivers in flood, area residents are likely to cast nervous glances at each new cluster of thunderstorms in the days to come. Were August to proceed through its remaining nine days without an additional drop of rain, the month -- with 6.40" on the books to date -- would rank 13th wettest of the past 137 Augusts.
There hasn't been a wetter 20-day August open at the city's official rain gauge since 1990 when 7.25" had fallen by this date. Only seven other Aug. 1-20 periods since 1871 have been wetter. But the story is an even wetter one in areas around the city. WeatherBug rainfall sensors in northwest suburban Palatine have tallied 13.05", while 9.82" has fallen at Highland Park and 9.33" in Glencoe.
Hurricane Dean, headed for what could be a calamitous landfall Tuesday in Mexico's Yucatan Peninsula, was declared a "catastrophic" Category 5 at 8:35 p.m. Monday evening when sustained winds reached 160 m.p.h.
--By Tom Skilling, WGN-TV Chief Meteorologist

Thanks to Jeremy and Sarah for for these photographs of the impact across our northern suburbs of this past weekend's extraordinarily heavy rainfall. Doppler radar esimtates put 6"+ down in Kenosha County and observer reports into our office indicate a huge swath of the metro area wound up with as much as 4"+ of rain. Jeremy and Sarah tell us these photos show the swollen waters of a creek in Lake in the Hills and the Fox River out of its bands just below the dam in Algonquin. Many thanks for the great shots!
--By Tom Skilling, WGN-TV Chief Meteorologist

Photos courtesy of Jeremy and Sarah

Not only have rivers in the Chicago area risen--among them the Des Plaines, expected to crest a foot and a half above flood stage according to current forecasts--Wisconsin's Lake Geneva is up as well. Eric Sorensen, Chief Meteorologist at WREX-TV and longtime visitor to the Lake Geneva area, has sent us these pictures. He tells us:

"In thirty years, I can't ever remember Lake Geneva being any higher than today! Last night, the water level was a few inches below our pier ... now it's lapping at the cross-boards. The water going over the spillway in downtown Lake Geneva was a deafening roar! The water spilled onto the hotel parking lot at Houlihan's. Several large mouth bass were seen in the parking lot! The water then flowed over streets toward Wells Street where it eventually all drained into the White River (the only outlet of Lake Geneva)."

Thanks for the pictures and the update, Eric!

--By Tom Skilling, WGN-TV Chief Meteorologist

Photos courtesy of Eric Sorensen

FLOATING AWAY AS AUGUST RAINFALL EXCEEDS 10 INCHES
As I gaze upon my lush yard that currently resembles the Amazon rain forest I think back to parched, dry appearance it had just a few weeks ago. August continues to amaze me with its recent penchant for producing heavy rainfall here.

August 2007 rainfall in Arlington Heights IL
4th .05"
5th 1.70"
6th .50"
7th 2.13"
8th .59"
9th .09"
12th .37"
14th .42"
15th .09"
18th .11"
19th 2.94"
20th 1.10"

Monthly total to date for August 2007 10.09" with undoubtedly more to come!

Waterlogged yard after more than 10 inches of rain
Photo by Steve Kahn

HIGH WATER AT LAKE ARLINGTON

Partially submerged bench illustrates the high water level at Lake Arlington after recent heavy rains.
Photo by Steve Kahn

The National Weather Service has northeast Illinois under a Flash Flood Watch today. Remnant moisture from Tropical Storm Erin feeding into strong southwest flow forced aloft over a warm front continues to produce a parade of showers and thunderstorms across northern Illinois.
"Training" storms developing and moving repeatedly over the same area gave rainfall totals of 1-3" or more Sunday, and similar action is expected today over much of the Chicago metro area. Two-day rainfall totals could exceed 5 inches in some locations.
Small stream, street/road and basement flooding are the most immediate problems anticipated, but already swollen larger streams and rivers could flood out of their banks in the coming days as the runoff quickly feeds into the hydrologic system.
Elsewhere around the nation, response to major flooding from 10-15" downpours was ongoing in Oklahoma, La Crescent, Minn., and La Crosse, Wis.
--By Paul Dailey, WGN Weather Center Meteorologist

These pictures of the incredible damage which Wednesday evening's thunderstorm outbreak left behind in northern Indiana come to us from Eric Richeke. Eric, who works with WLIT-FM here in Chicago, is a trained National Weather Service spotter and a Griffith, Ind., resident. His photos illustrate some of the storm damage which
NWS-Chicago Warning Coordination Meteorologist Jim Allsopp, who along with Lead NWS Forecaster Gino Izzi surveyed the scene Thursday, characterizes as "the most widespread and intense 'straight-line' blowdown I have ever surveyed." That statement, coming as it does from a veteran of our Chicago NWS-Forecast Office, speaks volumes given the fact that Jim, a regular participant at our Fermilab Tornado and Severe
Weather Seminar, has been in the business for decades! By the way, Jim and Gino suspect straightline wind gusts may have reached 120 m.p.h. in spots across northern Indiana Wednesday evening. Many thanks, Eric, for the great photograph -- and give our best to your colleagues at WLIT-FM!
--By Tom Skilling, WGN-TV Chief Meteorologist

Photos courtesy of Eric Richeke

The thunderstorms which ended up roaring across the Chicago area, generating damaging 50 m.p.h. gusts in the predawn hours last Sunday (Aug. 12), had just passed Hayward, Wis., last Saturday evening (Aug. 11) when the photo below was snapped by Anson Mount. Many thanks for sharing this beautiful shot with us, Anson!
--By Tom Skilling, WGN-TV Chief Meteorologist


Photo courtesy of Anson Mount

With a warm front poised just to the west, widely scattered showers and thunderstorms will threaten the Chicago Air Show later this morning and afternoon. Tonight and Monday morning strong storms with heavy downpours could develop. Localized two to three-inch rains may cause flooding of streets and underpasses as well as some streams. T-storms will be in the forecast off and on through Friday, and rainfall totals for the week could exceed 4” at some rain gage sites. Heat and humidity will return to Chicago with 90°+ readings as early as Tuesday. Meanwhile, Hurricane Dean will feast on the warm waters of the Caribbean Sea as it passes south of Cuba on a westerly trek toward the southern Gulf of Mexico. Dean seems to be following a similar course as Hurricane Gilbert, which was the strongest hurricane to date in 1988. As it approaches the Yucatan Peninsula Monday, Dean’s sustained winds may peak out well over 160 m.p.h.
--By Paul Dailey, WGN Weather Center Meteorologist

Smoke off distant Idaho and Montana forest fires produced the red tint to the moon which caught the attention of many Chicagoans Friday night. The smoke rode westerly winds aloft and arrived at the 18,000-foot level.
Friday's 79 degree high was the second coolest daytime reading of the month and followed a morning low of 64 degrees at O'Hare -- coolest in nearly two weeks.
Eastbound t-storms erupted in the Plains and western Midwest Friday, towering to 60,000 feet. The storms pounded Rapid City, S.D., with 2.75"-sized hail and nearly 2" of rain. The stormy environment shifts into the Chicago area later Saturday and Saturday night.
In the tropics, Jamaica appears to be Hurricane Dean's next target. The storm -- a Category 4 with 145 m.p.h. sustained winds late Friday -- underwent explosive development once in contact with the bathtub-warm waters of the Caribbean. Dean is on a path similar to 1988's Gilbert, in which peak gusts reached 218 m.p.h.
--By Tom Skilling, WGN-TV Chief Meteorologist

A swath of intense wind damage produced by t-storms Wednesday night was concentrated in a 3 to 5 mile band wide from East Chicago and Gary in Lake County, Indiana southeast to Hobart and Merrillville and across Porter County. That’s the conclusion of a team from the National Weather Service which surveyed the area Thursday and attributed the damage to powerful straight line winds rather than a tornado. The team noted trees and corn were blown down uniformly in a southeast to south direction and lacked the rotary distribution which would have occurred in a tornado. Peak gusts were estimated as high as 100 m.p.h.
The storms have ushered the coolest air in nearly four weeks into the area. Chicago’s 77° high Thursday was the lowest daytime temp in 26 days. The cool-off sent downstate temps plummeting in the wake of thunderstorms—but not before Paducah reached 105°, its hottest reading in 4 decades.
-By Tom Skilling, WGN-TV Chief Meteorologist

T-storms, which went on to produce flooding 1”+ downpours, hail and 70 m.p.h. wind gusts, erupted rapidly Wednesday evening. Lightning data tells the story. The evening’s fast-evolving storms began as towering cumulus clouds with radar-scanned tops near 39,000 ft. around 7 p.m., then mushroomed to a height of 60,000 ft.—apparently energized in part by heat generated by the city and converging winds near the lake. Lightning discharges grew exponentially—exploding from just 54 cloud to ground strokes in ten minutes around 7 p.m. to nearly 3,500 by 9 p.m.
Rainfall grew heavier as the storms swept across the city’s South Side totaling 1.14” in under an hour near the 5000 block of South Archer. Local 1.50”+ totals innundated NW Indiana where hail and powerful winds prompted t-storm warnings. A radar-detected tornadic circulation in Porter County led to a tornado warning while a 69 m.p.h. straight line gust was clocked at Gary.
--By Tom Skilling, WGN-TV Chief Meteorologist

Hail and powerful winds accompanied storms which swept southeast Lake County, Indiana. These photos from the Crown Point area came to us from Amanda Pickett. Thanks Amanda!

-Tom Skilling

Photo courtesy: Amanda Pickett

Our friend Chuck Hagen captures this dramatic lightning strike near Ford City on Chicago’s South Side around 8 pm Wednesday evening. Chuck goes on to say:

“This is a single strike that put down a few bolts at one time, something I didn't realize until I loaded it to my computer. I darkened the photo a bit reveal the powerful strike.”

Thanks for another terrific photo, Chuck!

- Tom Skilling

Photo courtesy: Chuck Hagen

It’s been wet this month and additional thundery rains are on the way. The rains have kept lawns green, fostered the best corn and soybean crops on area farms in memory and shielded the Chicago area from the string of hot days which have broiled much of the nation’s midsection. St. Louis, where the mercury has climbed above 90° every day this month, has accumulated more 90° temperatures in the past two weeks than Midway Airport has seen all summer. Yet, despite all the rain and the limited number of truly hot days, the month has managed an average of 78.0° at the O’Hare —a reading 5.7° above the long term average and warm enough to qualify as the third warmest open since 1959.
The tropics continue to heat up. Tropical Storm Dean threatens to become a major 110+ mph hurricane before this weekend and Tropical Storm Erin may form in the Gulf and head toward Texas. Trop. storm watches were hoisted there Tuesday evening.
--By Tom Skilling, WGN-TV Chief Meteorologist

Mike Frankowski was good enough to share these amazing photographs of some of the lightning discharges which accompanied Tuesday morning’s southeastbound thunderstorms. Thanks Mike!

Tom Skilling

Photo Courtesy: Mike Frankowski

These surreal-appearing cloud formations were generated as the powerful, derecho-like squall line which swept the Chicago area reached downstate central Illinois near the Decatur area Tuesday. Our thanks to Paul Hadfield, who is responsible for these photos. Paul writes:

“The outflow generated by dying storms up near Chicago kicked up a heckuva show at it crashed into Macon county. It should come as no surprise why several people were watching--- however nothing in either this or the last set (of storms) was the least bit severe; it barely even rained.”

Tom Skilling

Photo Courtesy: Paul Hadfield

A line of powerful, swift-moving t-storms threatens to rake sections of the Chicago area Tuesday morning after battering the Dakotas and Minnesota with 60 m.p.h. gusts and hail the size of golf balls. Hailstones produced by the 55,000 ft. tall storms covered the ground to a depth of 3” at Fort Ripley, Minn. More than 100 reports of severe weather had been logged late Monday evening by the Storm Prediction Center.
The squall line which could sweep parts of northern Illinois early Tuesday, is referred to as a derecho by meteorologists—a feature noted for its bow-shaped appearance on weather radar screens and its ability to endure for hours, producing wind damage over hundreds of miles of terrain. Another derecho Sunday night into Monday morning, left a swath of damage from the Dakotas south to Missouri.
Blistering heat—like the 107° record high at Rapid City, S.D. Monday—is fueling the t-storm eruptions.
--By Tom Skilling, WGN-TV Chief Meteorologist

After a sunny and warm Monday, the overnight hours will likely feature a blast of thunderstorms similar to those that raked the area early Sunday morning packing wind gusts to 50 m.p.h. and brief but heavy downpours. With searing triple-digit heat anchored from the southern Midwest to the Gulf Coast and a northwesterly jet stream across the upper Midwest, Chicago lies in a favorable path for repeat episodes of thunderstorms arriving from the northwest.
Weather across the Chicago area will remain unsettled through the week as a frontal system separating hot, steamy weather to the south from cooler, drier conditions on its northern flank wavers across the region. Meteorological setups like this favor the development of nocturnal thunderstorms in the Midwest.
The tropics are becoming active as mid-August approaches. In the Pacific, Hawaiians are nervously watching the approach of powerful Hurricane Flossie.
--By Steve Kahn, WGN Weather Center Meteorologist

With weather patterns remarkably similar to last week’s, Chicago is in line for a continuation of the recent warm, muggy weather punctuated by several periods of showers and thunderstorms. With dew points flirting with steamy Gulf-Coast-70º levels, episodes of heavy rainfall are possible as waves of t-storms amble through the area. The week promises to be an unsettled one as a frontal system oscillates across the region, generating a lot of cloudiness and triggering periodic thunderstorms.
Searing heat continues to bake the South, where triple digit readings shattered records from Texas to South Carolina Saturday. Baton Rouge, Louisiana led the “heat parade” with a scorching 104º.
With a little luck night skies may be clear enough here to allow viewing of the spectacular Perseid meteor shower which peaks Sunday night with a possibility of viewing more than 100 meteors each hour.
--By Steve Kahn, WGN Weather Center Meteorologist

It's back to the 90s this weekend over much of the metro area, extending to 14 and 15 the number of consecutive above-normal days here. August's warmer-than-normal trend -- nearly 6 degrees above average -- has pushed the month's ranking to 3rd warmest at O'Hare since 1959.
Saturday's light easterly winds protect the narrow corridor within a few miles of the lake from the area's hottest temperatures as readings there hold to the mid 80s. But on Sunday, the heat is to extend up to and over the shoreline as SW winds take hold.
Several potential complications arise Sunday. Oppressive levels of humidity are predicted with dewpoints surging into the mid 70s -- similar to tropical rain forests. In addition, the atmosphere is to become incredibly unstable -- i.e. temperatures are to plummet vertically at a much faster pace than usual. Add to the mix converging winds along a cold front, a vigorous jet stream above and atmospheric energy levels at the upper end of the spectrum, and powerful storms may erupt over parts of the area.
--By Tom Skilling, WGN-TV Chief Meteorologist

Friday brings the area’s first break in daily thunderstorm eruptions in a week. A final t-storm late Thursday evening—with a cloud top to just 20,000 ft.—produced surprisingly heavy rain. An inch of rain fell over sections of suburban Elgin before the cell weakened as it traversed DuPage County. Doppler radar tracked a modest circulation aloft with the storm for almost 45 minutes. And, what appeared to be a funnel cloud was photographed around 9:15 p.m. in near Elgin. But, in the end, the downpour-generating t-storm produced only a handful of cloud to ground lightning strokes and any circulation never made it to the ground.
Storm downpours have hit one section or another of the Chicago metro area in nine separate clusters since Sunday. Total rainfall in some west and north suburban locations has reached 4 to 7-inches—as much or more than a full August. Not all areas have been as wet. Midway Airport has recorded just 1.26” for the period.

--By Tom Skilling, WGN-TV Chief Meteorologist

Michael Frankowski sent us this picture from South Elgin of a wall cloud and what appears to be a lowering funnel at around 9:15 p.m. Thursday night. This funnel was part of an isolated low-topped supercell that developed north of Rockford and slid southeast into the northwest suburbs along and near Interstate 90. Despite the fact there was very little lightning associated with the storm, National Weather Service personnel in Romeoville, IL confirmed that there was enough rotation detected by Doppler radar to attract their attention. The apparent funnel never did touch down and the storm quickly dissipated by 10 p.m. as it moved into northern Du Page County.

-Mike Hamernik, WGN-TV Weather Center CLTV Meteorologist

Photo credit: Michael Frankowski

Dan Hanson, who does such a great job of keeping us informed of meteorological happenings in the beautiful North Woods, sends us these shots of his drought-stricken yard. He says the fire danger in his region near Winter, Wisconsin is high. In his e-mail to me, Dan goes on to say:

" Up here in Winter we have not seen rain now for about 2 weeks now. My back yard has gone from green to brown. I enclosed you some photos I took a few minutes ago."

Thanks for the revealing photos, Dan, and here's hoping the rains come sooner rather than later. Models are depicting the potential for t-storms on several occasions during the coming week. But, droughts have a way of feeding on themselves and time will tell whether the needed thunderstorms materialize.

-Tom Skilling

Photo courtesy: Dan Hanson

Tornado siren systems were activated across many northwest suburbs Wednesday afternoon around 3pm as a result of numerous sightings of funnel clouds like these as well as Doppler radar velocity information which indicated the presence of a tornadic circulation. The thunderstorm responsible towered to 40,000 ft. at one point according to radar scans and moved from northern Kane to northern Cook Couty. George Issacs was the photographer and his shots are spectacular. George tells us these were taken over a developmental cycle which lasted eight minutes. Thankfully, no touchdowns were reported and the funnels eventually dissipated. Many thanks George for sharing these with us and those visiting our blog.

Tom Skilling



Photo courtesy: George Issacs

The 8th eruption of thunderstorms since humid air took up residence here last Sunday produced these spectacular lightning strokes in Thursday’s pre-dawn hours across Chicago’s southern suburbs. Chuck Hagen photographed the storms west of I-57 near the Will and Kankakee County borders around 3:45 am and shares them with us. I am always amazed at Chuck’s work and these shots are no exception. He tells us the storms put on quite a show. MANY THANKS for sharing these with us Chuck!

Tom Skilling

Photos courtesy of Chuck Hagen

The muggiest air of 2007, which first reached the area Sunday, exploded Wednesday for a fifth consecutive day into downpour and funnel-cloud producing t-storms. Doppler radar velocity measurements identified tornadic rotation around 2:45 p.m. Wednesday afternoon in northern Kane County. A flurry of funnel reports ensued from Maple Park to Schaumburg, prompting the activation of tornado sirens. A quick 1”+ of rain hit in sometimes blinding downpours. No touchdowns occurred beneath the 40,000 ft. tall storms and flooding proved the major culprit. The same westward moving lake breeze front responsible for the mid afternoon storm eruption produced the day’s second thundery cloudburst—this one focused on Sugar Grove and Aurora in southern Kane County. Rainfall rates there reached 3.50”/hour with radar storm estimates topping 3”. Significant flooding was reported in the area on Illinois Route 47.
--By Tom Skilling, WGN-TV Chief Meteorologist

Many thanks to Gary Alperin for sharing this shot of a wall cloud taken in the midst of Wednesday afternoon's severe storm outbreak across Chicago's northwest suburbs. Thanks too to fellow WGN-TV meteorologist Steve Kahn for relaying this to us for us on our blog.

Tom Skilling

Spectacular lightning displays—especially across our southern suburbs—accompanied the latest thunderstorm eruption very early Wednesday morning. David Mayhew, who's incredible photography has been a favorite of ours for years, capture several of the intracloud and cloud to cloud lightning discharges over the city between 12 midnight and 2 am Wednesday morning and shares them with us. Many thanks David!

Tom Skilling


Photos courtesy of David Mayhew, Chicago

Tornado warnings were issued for northern Kane and northern Cook Counties just before 3 pm Wednesday afternoon. The Weather Service's Doppler radar detected rotation and conventional radar reflectivity scans of the storm indicated a well defined "hook echo"--indicative of rotation. In addition, a funnel cloud was sighted a quarter of the way to the ground near Maple Park in Kane County around 2:50 pm. The thunderstorms, with radar scanned cloud tops to 38,000 ft., flared along an inland moving lake breeze front in the day's heat and humidity (temps in the mid 80s and stifling dewpoints in the low and mid 70s). Atmospheric energy calculations derived from vertical temperature/moisture readings indicate an atmosphere was primed to erupt. As these photos taken by Chris Gach of Carpenterville at 2:52 pm Wednesday show, rainfall in the storms has been impressive. A viewer reports more than an inch down in under an hour near Schaumburg. A number of funnel cloud sightings have been detected by the public and trained National Weather Service spotters since 3 pm--but there have been no confirmed touchdowns nor has there been any damage reported as of the time of this posting (3:28 pm Wednesday). Our high resolution RPM model is suggesting these storms will diminish as the afternoon progresses. New, better organized storms later Tuesday night threaten a new wave of downpours on saturated ground and are behind the flash flood watch in effect through tonight. In addition, the area is outlooked into Thursday for potential severe weather by NOAA's Storm Prediction Center.

-Tom Skilling
WGN-TV Chief Meteorologist

Photos courtesy of Chris Gach, Carpentersville, Illinois

The winds of two dust devils, which occurred within two minutes of each other at one of Peninsula State Park's beaches in Door County, are pictured in these photographs. The photographs come to us from Jonathon Durr, who is vacationing there with his family. Jonathon tells us the winds were strong enough to hurl a raft at him from 40 feet away. Dust devils most often result when localized (small scale and concentrated) heating of the ground heats the air above producing thermals (buoyant upward moving columns of air). As air rushes in to replace the rising air, a swirling vortex of air, frequently able to entrain dust and other debris, develops. Many thanks to Jonathon for sharing the photos with us!

-Tom Skilling

Photos courtesy of Jonathon Durr

Flooding of historic proportions gripped the Rockford and Belvidere areas Tuesday forcing residents from their homes and vehicles in the hardest hit locations. Those with whom we talked Tuesday characterized the latest cloudburst as potentially as bad—if not worse—than last September’s Labor Day cloudburst. That devastating flood was the area’s worst in at least 30 years.
The latest storms, which struck in Tuesday’s predawn hours, drenched Belvidere with 6.30” while saturating Rockford with 5.25”—accumulations which produced 100+ and 75-year floods in those communities respectively according to Illinois state climatologist Dr. Jim Angel. Rainfalls of 4+” extended east across a wide swath of Lake and McHenry counties, forcing road closures for a time early Tuesday.
---By Tom Skilling, WGN-TV Chief Meteorologist

Overnight flooding in Rockford and Belvidere is of historic proportions. Dr. Jim Angel, our Illinois state climatologist at the Midwestern Regional Climate Center, reports Rockford's devastating overnight rains constitute a 75-year flood while Belvidere flooding is a 100+ year event.

--Tom Skilling

Rockford, Belvidere, Cherry Valley area reeling after overnight deluge; more than half a foot of rain hits some sections--and more's coming!

The heavens opened overnight over a wide swath of northern Illinois unleashing a 6"+ deluge of thundery rainfall for hours overnight night which left many areas under water with roads closed. The flooding was so severe, it necessitated water rescues like the ones pictured here between 7 and 7:30 am this morning in Rockford and photographed by Chris Long . From Rockford suburb Cherry Valley east to Belvidere, we've been inundated by stories of serious flooding which has trapped people in their homes and stranded many in vehicles on flooded roads. A number of Rockford residents with whom we've talked are calling the latest round of flooding worse than the Labor Day 2006 flooding there which resulted from 6.51" on Rockford's southeast side (interestingly, the official rain gauge at the airport in Rockford record under 0.75" on that occasion).
WIFR-TV Rockford Meteorologist Mark Henderson, a WGN-TV weather office alum, has e-mailed us the following:

"It really is an amazing story -- flood waters made it within 20 feet of my house. Sadly, we've heard stories about dozens upon dozens of people who had just finished rebuilding after last year's flood who now have to start over once again. It really was the exact same area hardest hit yet again. This, in my estimation, was even more noteworthy than the horrific flood of last year! So many major thoroughfares closed for hours upon hours....."

The overnight rains mark the fifth eruption of thunderstorms in the current stiflingly humid weather regime which established itself here over the past weekend. And, it's not over. More storms are predicted. They are likely target specific sections of northern Illinois---hammering some area, all but bypassing others. The Chicago area is outlooked for potential severe weather and may experience thundery downpours on several additional occasions later Tuesday into Thursday. Dewpoints, a measure of atmospheric moisture, are in the mid 70s and have reached the low 80s at some locations Tuesday afternoon--tropical rain-forest levels and a sign the atmosphere is still literally dripping with moisture!


-Tom Skilling
Chief Meteorologist, WGN-TV

The most humid air in a year erupted into thunderstorms for the third time Monday blasting sections of the Chicago area with 40 mph gusts, prodigious cloud-to-ground lightning and rains of up to 4”. Even before Monday’s rains hit, Chicago’s Aug. 1-6 rainfall (1.46”) ranked the 19th heaviest for the period since records began 136 years ago. Blinding rains and, at one point Monday evening more than 3,000 cloud-to-ground strokes in 10 minutes, walloped some south and western suburbs. Western DeKalb County—7 miles southwest of DeKalb—proved ground zero for the heaviest storms. There 3.82” of rain fell between 3:50 p.m. and 6:50 pm—2.90” of it in just 30 minutes.
Blistering heat downstate—this summer’s hottest yet—provided the fuel for the storms. Temps topped out near the century mark at St. Louis (99°), 99° at Centralia and 100° at Mt. Vernon. The heat index at Taylorville reached a staggering 113°.

-By Tom Skilling, WGN-TV Chief Meteorologist

Powerful t-storms, with cloud tops near 58,000 ft., swept into northwest Indiana late Monday. This cloud to ground lightning stroke was photographed by Amanda Pickett. Thanks for the great shot Amanda!
-Tom Skilling

Photo courtesy: Amanda Pickett

Thunderstorms erupted Sunday afternoon and evening and produced this tornado just after 6 pm in Chicago’s southwest suburbs. The National Weather Service issued a tornado warning for the area around 6:09pm after a circulation was detected by Doppler radar. A funnel cloud was reported minutes later over Bolingbrook around 6:13 pm Sunday and 6:18 pm over Romeoville. The funnel, with a circulation which appeared to reach the ground and is suspected responsible for some damage to Romeoville area roofs, was photographed by a number of our viewers, each of whom we thank for sharing them with us for you to see here on our blog. Sunday evening’s storms, which focused on Chicago’s south suburban area, followed downpours Saturday night which drenched the northern half of the metro area. Local 3” amounts occurred in the thundery deluges in sections of Lake and McHenry counties. New storms threaten Monday night and early Tuesday---then again Tuesday afternoon or evening. Given upper 70-degree dewpoints, the highest of 2007, the predicted passage of a warm front late Monday night and a cold front later Tuesday along which winds are to converge, and an abnormally strong late summer jet stream aloft, the potential for flooding and severe weather in at least sections of the metro area is uncomfortably high. This is a situation to monitor carefully.

Many thanks again for those whose tornado/funnel clouds pictures appear here and who have been kind enough to share their photos with us!

Tom Skilling

Photos courtesy: Jennifer Scamardi, Romeoville

Photos courtesy: Matthew Collier, Firefighter/Paramedic

Photos courtesy: Lt. Frank Laskey, Lockport Township Fire District

Northeast Illinois was served up a severe weather mix Sunday, and more of the same could be in store for the next few days. A nearly stationary front will be oriented west-east through southern Wisconsin just north of the Illinois border, and southerly winds will maintain hot, humid conditions over the metro area most likely into Thursday.
Early Sunday morning, strong thunderstorms spread into northern Illinois dumping from a half inch of rain along the Interstate 88 corridor to as much as 3 inches along the Illinois-Wisconsin border. Then later in the afternoon, very strong thunderstorms fired primarily along and south of Interstate 80 with torrential downpours of 1-2 inches per hour prompting flash flood warnings. Outflow winds gusted to 70 m.p.h. at Crete in southern Cook County, and a small tornado reportedly touched down in Romeoville.
Timing is difficult, but the next organized surge of storms may be due later tonight and Tuesday.
--By Paul Dailey, WGN Weather Center Meteorologist

Overnight showers and thunderstorms should gradually diminish during the morning hours. As the storms moved out of Iowa and NW Illinois, some “trained” (repeatedly passed over the same area) resulting in localized flooding where rainfall totaled well over an inch. The storm-triggering warm front is expected to move north of Chicago this afternoon, and as it does, clouds will break and winds shift to the south. The front should lie just to the north, orienting west-east across southern Wisconsin, the first half of the week.
Chicago will thus be situated on the northern edge of a hot, humid air mass centered over southern Missouri and Arkansas. An Extreme Heat Warning is in effect today and an Extreme Heat Watch for the remainder of the workweek in the St. Louis area. Meanwhile, Chicago will experience daily flirtations with 100° afternoon heat indices.
--By Paul Dailey, WGN Weather Center Meteorologist

Resurging heat, with implications to Chicago's weekend weather, fueled waves of powerful thunderstorms which unleashed a half foot of rain on sections of South Dakota late Friday. The mammoth storms towered to heights of 54,000 feet and flared as hot, humid air was lifted into an unusually strong mid-summer jet stream. Shifting wind direction with height generated storm rotation -- always an ominous development. Grapefruit-sized hail bombarded Rapid City, S.D., breaking windows, and at least two small tornadoes touched down briefly near St. Francis, S.D., and Sparks, Neb. Rainfall Friday reached 5.92" at Chamberlain and 2.36" at Pierre -- both in South Dakota—3.10" at Pine Bluffs, Wyo., and 2.61" at Fessenden, N.D.
The warm front responsible for the Plains storms is eastbound. It reaches Chicago late Saturday night. Increasing clouds and SE winds off the lake today threaten potentially prolific lightning-producing thunderstorms overnight.
--By Tom Skilling, WGN-TV Chief Meteorologist

Thursday’s 91° high was the year’s 13th daytime reading at or above 90°, and the third time this summer area residents have been treated to three consecutive 90° highs. Peak readings in this most recent hot spell of the season first topped 90° on Tuesday, then reached 92° Wednesday and 91° Thursday. This marks only the 6th time in the past four decades at Midway Airport that an August has opened with back to back 90s.
Meteorological summer has averaged 72.8° in Chicago—virtually identical to the same period a year ago and 1.6° above the 137-year long term average. That’s qualifies the 2007 season as Chicago’s 38th warmest since 1871. While humidities pull back Friday into Saturday, heat resurges strongly Sunday afternoon into next week—a development sure to push our summer temp ranking even higher.

--By Tom Skilling, WGN-TV Chief Meteorologist

With temperatures at their lowest levels Thursday morning and dewpoints in the low 60s around sunrise Thursday, Amanda Pickett photographed this ground fog near Crown Point in northwest Indiana. Amanda tells us she was up early and seeing this was her gift for rising early. Many thanks for these beautiful shots, Amanda!

Tom Skilling

Photos courtesy of Amanda Pickett, Winfield, Indiana

Though it’s become hot in recent days, the area has certainly dealt with more debilitating heat in the past. Chicagoans were saddled with triple-digit heat indexes as the mercury soared to 97° a year ago. But, gentle lake breezes and fairly moderate humidity levels, including low and mid 60° dew points instead of Gulf Coast level 70°+ dew points, have spared the area the full impact of the heat up to this point. Make no mistake, working outdoors hasn’t been easy. But, truly humid air—like that expected to take hold later this weekend into next week—would already have pushed heat indexes to dangerous 100°+ levels.
Thursday marks the sixth consecutive day with high temps warmer than the day before. It’s also the 13th of the past 15 days to feature a lake breeze. Pollutants have been building. An Air Pollution Action Day has been declared Thursday. Ozone levels reached 102 parts per billion in some areas late Wednesday.
--By Tom Skilling, WGN-TV Chief Meteorologist