October 2007 Archives

Chicagoans haven’t experienced an October milder than the one just completed in 36 years—since 1971. The month finished with an average temperature of 60.4° at Midway Airport—a reading well above the 54.1° October average since 1928. Only four Octobers have been milder there in the past 80 years.
This autumn’s mild, dry character is typical of a Niña autumn. La Niñas are declared when ocean temps in the central equatorial Pacific drop 0.5° or more below normal over three consecutive months, a shift which produces weather changes globally. Among them is the tendency for autumns to be mild and dry over a huge swath of the country. Winters can be a different story. La Niña winters have been known to turn wetter in the Midwest, roughly from Chicago south. And, while temps in these winters often average above normal, La Niña winters can be volatile—featuring spells of bitter cold interspersed with spells of mild Pacific air.
--By Tom Skilling, WGN-TV Chief Meteorologist

Our friend and regular photographic contributor Amanda Pickett from Winfield in northwest Indiana has sent us this Wednesday photo of that area’s spectacular fall colors. Many thanks for sharing this with us Amanda!!

Tom Skilling

Photo Courtesy: Amanda Pickett

Powerful NE winds rake Florida a fourth consecutive day Wednesday, threatening to worsen beach erosion already being characterized as extreme in Palm Beach County by the National Weather Service. Winds topped 40 m.p.h. on the state’s east coast Tuesday, sending 6-8 ft. breakers into area beaches while generating 14-18 ft. swells offshore. Pounding waves collapsed a retaining wall on the coast at Lantana, just south of West Palm Beach, and the relentless gales pushed tides at Jacksonville Beach 4.6 feet above sea level, sending sea water across backyards near Oak Landing.
The winds were not directly related to Tropical Storm Noel, which churned along the north Cuban Coast Tuesday. Instead, the huge variation in air pressure between Noel and a sprawling high pressure to the north, produced an environment for a huge swath of easterly winds which swept much of the Southeast coastline—not just Florida.
--By Tom Skilling, WGN-TV Chief Meteorologist

Our meteorological colleague Richard Koeneman shares these spectacular shots taken Tuesday afternoon of the fall colors which have come to the mountains of western North Carolina near Asheville. The panoramic view of the mountains were snapped earlier in the day and show daybreak stratus diminishing in the rising sun in forested mountains ablaze with fall color. Richard tells us the region’s peak colors will arrive there in a week or two.

Tom Skilling

Photo Courtesy: Richard Koeneman

Many thanks for Gary Wojton for sharing this amazing shot of the fall colors which are so stunningly evident in this photo! Gary tells us he took this outside Oakton Community College in Des Plaines. Thanks for sharing this with us, Gary!

Tom Skilling

Photo Courtesy: Gary Wojton

Tuesday's gusty southwest winds deliver the 40th day of 70-degree-plus temperatures since Sept. 1 in what has been one of this area's mildest autumns here. With the three-month meteorological fall season (September-November) nearing the two-thirds mark, Chicago's 63.9-degree average temperature to date ranks 8th warmest of 137 comparable periods on the books since weather records began in 1871. Daily temperatures have averaged above normal 78 percent of the time the past 59 days.
Florida and much of the Southeast Coast is being pounded by a nor'easter. Huge barometric pressure variations between a sprawling high pressure off New England and late-season Tropical Storm Noel, which moved from Haiti into the South Atlantic Monday, are whipping up the 40-50 m.p.h. coastal gusts and towering 1-2 story waves predicted to continue over Florida’s east coast Tuesday. Northwest-bound Noel could pass within 130 miles of Miami on Wednesday.
--By Tom Skilling, WGN-TV Chief Meteorologist

Fall colors out across northern Illinois and AT or JUST PAST peak:

Photos courtesy: David Lindgren

Frost was widespread Sunday morning and scattered across the area but less widespread Monday, on the precipice of a move into a substantially milder weather for the closing days of October, 2007. These beautiful shots, capture a morning mist rising in the chilly morning air above Willow Pond in Prospect Heights as well as widespread frost evident on grassy surfaces as well as the roof of the home pictured here. The current state of the area's striking fall colors (as of Oct. 28-29) and evidence of the region's annual geese migration is also quite evident. This area's fall colors are at or are just beyond their peak across northern Illinois into northwest Indiana. The photos come to us from Jay Kleeman who has been generous in sharing his spectacular photos of so many area weather events over the years with us. MANY thanks Jay!
--By Tom Skilling, WGN-TV Chief Meteorologist

Our trans-Atlantic friend Mark Vogan sends us these morning shots from the United Kingdom of frost last week across Scotland. Mark, an avid weather enthusiast who keeps a close eye on weather trends in the UK as well as here in the U.S., wonders if it's not possible this autumn's earlier frost arrival might offer at least a hint on the nature of the coming winter across the UK. He tells us:

“Last year there was not one morning where the temperature dropped low enough to support frost. To the best of my knowledge the earliest frost of last year was October 31st. This year we had frost as early as mid September. Typically first frosts arrive in late October across the central lowland region, earlier in the highland valleys and glens.

With year after year of very balmy winters across the UK and the early arrival of frosty mornings in 2007 on the backside of the coldest September in Scotland since 1994, could we have a considerably colder winter ahead, even if we average overall warmer-than normal? I beleive this winter may bring back some true cold and perhaps a modest snowstorm, that perhaps blankets the ground for a 5-7 day period to produce a cold week of freezing days and bitter nights. Something we haven't seen much of over recent years. Any snow that has fallen of late has melted within a couple of days, with no cold air in to take advantage of the fresh snow cover.”

An interesting observation indeed and one which is worth watching as we move more deeply into the new cold season.
--By Tom Skilling, WGN-TV Chief Meteorologist

A strong southwest flow will establish itself over Illinois today and persist through Tuesday into Wednesday. Chicago's high temperatures today may end up some 10 degrees higher than the mid 50s experienced Sunday. On Tuesday, the warming will continue with unseasonable 70-degree readings forecast. On Halloween, some cloudiness may precede and accompany a cold front that is not expected to pass through Chicago until later in the afternoon. A much cooler air mass should then be in place the remainder of the week.
Meanwhile, Tropical Storm Noel formed just south of Hispaniola, and Sunday night the National Hurricane Center in Miami forecasted a slow-moving northward track which left Haiti, the Dominican Republic, southeast Cuba and Jamaica bracing for a foot or more of rain, extensive flooding and mudslides. Haiti was under a Tropical Storm Warning, and a Tropical Storm Warning and Hurricane Watch were in effect for southeastern Cuba.
--By Paul Dailey, WGN Weather Center Meteorologist

This autumn has not only been characterized by warm daytime temperatures, but by exceptionally mild nights as well. Before Sunday morning’s frosty lows, the city’s lowest official minimum temperature this fall had been just 39º and that was recorded more than a month ago on Sept. 15. Frost had been limited to some scattered occurrences at far inland locations.
All that is changing this week, as two more intrusions of cold air will bring some of the season’s lowest daytime readings, and frosty overnight lows as well. Some frost will be possible again Sunday night away from the heat of the city.
However, sandwiched between the cold snaps, a midweek warm-up will boost the mercury back into the 60s on Tuesday and Wednesday, raising prospects for another mild Halloween—a frequent occurrence here in recent years. Ten of the last 12 Halloweens have been warmer than normal.
--By Tom Skilling, WGN-TV Chief Meteorologist

This ninth weekend of meteorological autumn is to end up the season's chilliest to date -- 22 degrees below last weekend's temperatures which included an unseasonable late-season 80 degree Sunday high. Northerly winds -- in effect a 3,000-mile atmospheric conveyor belt extending from the northernmost tip of Hudson Bay south to Mexico's Yucatan Peninsula -- are encouraging chilly air to spill southward off northern Canada's growing snowpack into the U.S. A mammoth Canadian high pressure is behind the gusty 20 m.p.h.-plus north winds raking Chicago and much of the Midwest and is expected to import enough dry air Saturday afternoon that the area's sprinkly morning cloud deck should break.
The incoming chill set new low temperature records in the Pacific Northwest Friday in Seattle (35 degrees) and Pendleton, Ore. (22 degrees).
Though cool in Chicago Saturday, city residents shivered even more a year ago when the high only reached 45 degrees.
--By Tom Skilling, WGN-TV Chief Meteorologist

Chilly weather intensifies its grip on the area this weekend. The area is headed for its coolest Saturday/Sunday period in the 7 months since last April—a far cry from last weekend’s unseasonable 73° and 80° highs. The coming weekend’s temperatures will average more than 20° colder.
The meteorological autumn period which began Sept. 1 has been so warm that the other shoe eventually had to drop. The city hasn’t recorded a sub-40° temperature at Midway or O’Hare yet this month. That’s the first time Chicago’s advanced this far into October without a reading falling into the 30s or lower in 44 years. (Note: Normally cooler suburban areas have been cooler than in the city and low 30s have been reported in recent days. There’s been patchy frost in far western suburbs—e.g. in DeKalb County.)
--By Tom Skilling, WGN-TV Chief Meteorologist

October, until recently among the 7 warmest here since records began in 1871, has shifted meteorological gears in dramatic fashion. That was evident to anyone who braved Wednesday’s chilly temperatures amid wind gusts which topped 35 m.p.h. at times. The day’s 55° high was the coolest in two weeks and the second coolest daytime temperature of Fall, 2007 to date. By this time a year ago, fall had already produced 11 days as cool or cooler than Wednesday. October alone had averaged 11° cooler than the 61.4° on the books for the month’s opening 24 days this year.
What’s happened to Chicago’s temps in recent days—and what is predicted to occur in terms of temperatures over the coming two weeks—is stunning when compared to October’s opening week which averaged more than 13° above normal. By comparison, the coming week is predicted to run 3° below normal with a 1° deficit in week #2 as November gets underway.
--By Tom Skilling, WGN-TV Chief Meteorologist

Another spectacular shot of Tuesday evening’s beautiful sunset from Whiting, Indiana taken by Carolyn Szepanski. Carolyn, you’re great! Thanks for sharing this with us!

-Tom Skilling

Photo Courtesy: Carolyn Szepanski.

Thanks to our friend and Remington, Indiana weather observer Mary Anne Best for sharing these shots of Tuesday evening's spectacular sunset!

-Tom Skilling

Photo Courtesy: Mary Anne Best

International Space Station and the Space Shuttle visible from Chicago this evening (weather permitting) for 6 minutes.

We know from past experience that many of you may be interested is watching the International Space Station and the Space Shuttle move across Chicago area skies and want to provide you information on how to see it. Our astronomer Dan Joyce tells us the following is to be the sequence of events this (Wednesday) evening if you wish to view the southeast-moving International Space Station and the Space Shuttle from Chicago over a short 6 minute span.

6:43 P.M.: The International Space Station, a small moving object in the sky a little larger than a planet, will appear just above the west/northwest horizon at 6:43 p.m. moving southeastward.

6: 44 P.M. The Space Shuttle follows a minute later moving in the same direction

6:46 P.M. The International Space Station move to a position 26-degrees above the horizon—its highest point in the sky

6:49 P.M. The Space Shuttle sinks below the south/southeast horizon

Some areas of lake effect clouds, similar to those in the city as this is posted at 11:30 a.m. are expected to continue from time to time this afternoon and evening over extreme northeast Illinois and northwest Indiana and represent the only potential threat to viewing over sections of the Chicago metro area. But in areas farther west of Lake Michigan, clear viewing is expected. Clouds are expected to begin arriving -- but later tonight.

Tom Skilling
WGN-TV/Chicago Tribune Chief Meteorologist

Heavy rains walloped the southern Midwest Tuesday, swamping sections of Kentucky with as much as 5” of rain. Totals across the Blue Grass State included 4.13” at Lexington, 5.02” at Versailles, 4.62” at Ft. Campbell and 3.62” at Louisville.
Downstate Illinois got in on the rainfall bonanza tallying 1.41” at Vienna and 1.31” at Mt. Vernon. Clouds on the north flank of the wet system shrouded Chicago’s southern suburbs at the same time that uninterrupted sun poured down on the northwest half of the metro area. The cloud distribution led to a situation where southern areas warmed no higher than the low 50s while sunnier north suburban locations like Gurnee logged a 62° high.
California’s devastating wildfires spread amid howling winds and record heat Tuesday. Temps reached 100° at Anaheim, 99° at Santa Ana, Fullerton Airport and Costa Mesa.
--By Tom Skilling, WGN-TV Chief Meteorologist

Thanks to Mario DiLorenzo of Bartlett and Michael Leung of Chicago for sharing their pictures of tonight's beautiful sunset.

BUCKTOWN SUNSET

Photo by Michael Leung

BARTLETT SUNSET

Photo by Mario DiLorenzo

The meteorological party ended Monday. Temperatures, which only a day earlier surged to 80°, plummeted 30° by late Monday when readings hovered in the upper 40s and low 50s across the area—levels much closer to seasonal norms.
Sunshine returns Tuesday but the area is to remain locked in a cooler weather regime for the foreseeable future with clouds and rain next due late Thursday.
The heavens opened in New Orleans Monday producing extensive flooding. The thundery downpours reached 9” late Monday at Lacombe, La. (9.07”) and Picayune, Miss. (9.06”). One rain gauge in New Orleans proper indicated 7.37”.
The storm behind that Gulf Coast cloudburst is to bring desperately needed rain to the sections of the drought-ravaged interior Southeast. More than 4” is predicted from northern Mississippi and Alabama north to Tennessee over the next 5 days.
--By Tom Skilling, WGN-TV Chief Meteorologist

It should come as no surprise that Fall 2007, with its abundance of warm days, currently ranks 6th warmest out of 137 meteorological autumns since 1871. Sunday's average temperature of 70 degrees was 20 degrees above normal, and the city's 80 degree high marked only the 30th such 80-degree-plus occurrence this late in the season here.
However, weather patterns are showing signs of change, and a temperature decline beginning Monday afternoon will return readings here to near or below normal through the end of the month, though no exceptionally cold weather is expected.
Warm weather also covered much of the eastern U.S. Sunday, where several record highs were broken or tied, among them 81 degrees at Detroit, 80 degrees at Youngstown, Ohio, and 92 degrees at Midland, Texas. Hot 90-degree-plus weather is also forecast for parts of southern California Monday, where powerful northeast Santa Ana winds gusting to more than 80 m.p.h. are spreading more than a dozen wildfires.
--By Steve Kahn, WGN Weather Center Meteorologist

An intensifying storm in the Upper Mississippi Valley will not only boost temperatures here to rare 80º territory Sunday, but it will generate very strong south winds with gusts in excess of 40-45 m.p.h. If Sunday’s high reaches 80º, it will mark the latest such occurrence here in eight years (since 80º on Oct. 28, 1999).
While Chicago has been graced with warmer than normal weather much of October, residents are well aware that approaching late autumn’s chill cannot be too far away. Temps will crash Monday afternoon as winds shift into the northeast with highs the rest of the week to be at more seasonable levels hovering near 60º. An even stronger cool-down is expected by next weekend with readings struggling to reach 50º by Saturday.
A National Weather Service storm survey team investigated the devastating twister that struck Nappanee, Ind., Thursday evening, rating it an EF-3 on the Enhanced Fujita Scale with 136-165 m.p.h. peak winds.
---By Steve Kahn, WGN Weather Center Meteorologist

Days have been shortening here for over three months. By Saturday's close, Chicagoans will have witnessed the loss of four hours and 20 minutes of daylight, and can expect another hour and 14 minutes to vanish in the coming month. Saturday's 6:02 p.m. sunset is nearly 2-1/2 hours earlier than the 8:29 sunset on June 21 -- the day summer began and this area's longest day of the year. Remarkably, despite that loss of daylight and the resulting reduction in solar energy, this 8th weekend of meteorological autumn is to be unusually mild.
Temperatures will average 14 degrees above last weekend -- the season's coolest to date. Included in the warm-up is a predicted high of 80 degrees Sunday, a reading rare this time of the year. Just 0.3 percent of the 80 degree and warmer temperatures on the books here have occurred this late in the season. The city has logged 9,211 highs in excess of 80 degrees since records began -- and only 29 of them have occurred beyond Oct. 20.
--By Tom Skilling, WGN-TV Chief Meteorologist

Here are just a few of many great photos we've received of Thursday's storm. Thanks to everyone who sent photos in!
—WGN-TV Weather Center

Thursday's storms as viewed at 5:30 p.m. from western suburban Oswego

Photo courtesy: Jeri Jahnke, Oswego, Illinois

Thursday’s storms as viewed from the Fox Valley

Photo courtesy: Matthew Liechota, Batavia, Illinois

Thursday's late day thunderstorms as viewed from a distance from DeKalb County

Photo courtesy: David Lindgren, Shabbona, Illinois

Michael Foradas, who snapped this photo of Thursday's violent evening storm from the 60th floor of the AON Center, says hail crashed intensely into the windows just minutes after this photo was taken! With winds unimpeded by frictional drag at such heights, the hail was able to hit with particular force.

An e-mail from another Chicagoan, Bill Kijek, who was caught around 5:30 p.m. in yesterday's storm while walking near Clark and Adams, indicates he saw what he thought was white smoke approaching. It turned out to be the rain and hail shaft (which you see on the time lapse of the storm from one of our WGN Hancock cameras) and the approaching downburst, which ended up generating 60 m.p.h. gusts in the Loop. Bill reports it rained for five minutes at the height of the storm harder than he's ever seen it rain before, and that the winds sound like, as he put it, "...the proverbial freight train, then it was gone." Bill's description is that of a downburst. Thanks to all of our readers and viewers for sharing their extraordinary pictures and accounts with us!
--By Tom Skilling, WGN-TV Chief Meteorologist

Downbursts occur when cool air plunges earthward out of thunderstorms, often during driving downpours. Once making contact with the ground, the powerful winds fan out in all directions, setting up the powerful straight-line winds so many of us associate with t-storms. Winds hit 60 m.p.h. in the Loop in a downburst late Thursday. It was captured by WGN time-lapse cameras on the Hancock Building. The footage is posted on the wgntv.com website.
Winds reached 74 m.p.h. as they roared offshore at the Harrison-Dever Crib just off the Chicago shoreline. Other thunderstorm wind gusts late Thursday reached 72 m.p.h. at Midlothian. The storms bombarded parts of Joliet with golfball size hail (1.75” in diameter). During the evening, the t-storms spread east into Indiana and Michigan, where a late night tornado (9:25 p.m.) south of South Bend seriously damaged homes and caused injuries.
--By Tom Skilling, WGN-TV Chief Meteorologist

A view from the north of the developing storms taken at Waukegan Airport was sent to us by pilot Anson Mount.

Photo by Anson Mount

Storm photos taken by WGN Weather Center intern Meredith Garofalo while storm chasing
Thursday evening.

Photo by Meredith Garofalo

Thanks to Chuck Hagen of Oak Lawn who captured this evening's thunderstorm activity for us while driving through the Monee area.

Photo by Chuck Hagen

Photo by Chuck Hagen

THUNDERSTORM OVER THE LOOP
Thanks to Sven Svede and Tiffany Dunlevy for capturing these spectacular pictures of severe thunderstorm activity that raced through the city and southern suburbs earlier this evening.

Photo by Tiffany Dunlevy

DEVELOPING THUNDERSTORMS VISIBLE FROM SCHAUMBURG

Photo by Sven Svede

Severe thunderstorms developing rapidly, hail in the Loop

Marble size hail fell in the Loop on Michigan avenue and 60 m.p.h. wind gusts measured by the WeatherBug sensor atop the LaSalle Bank Building this evening just after 5:30 p.m. as severe thunderstorms rolled northeast into the city from the Joliet area. Shortly after
5:45 p.m. golf-ball size hail was reported in Joliet and winds gusts to 75 m.p.h. were clocked at Wilmington in Will County.

High winds blowing from the southwest, not associated with thunderstorms but directly related to the intensity of the storm system sweeping the Midwest have been raking the Chicago area throughout the afternoon and evening hours.

Some of the highest wind gusts are recorded on our WeatherBug network include
Tonti Elementary School Chicago 53 m.p.h.
Curie Metropolitan High School Chicago 52 m.p.h.
Simeon Academy Chicago 52 m.p.h
Bednarcik Junior High Aurora 51 m.p.h.
Gale Academy Chicago 50 m.p.h.

Steve Kahn WGN Weather Center Meteorologist

Powerful winds raking the area beneath jet stream, Chicago continues on west side of severe weather risk area into early tonight

A tornado watch has just been posted by NOAA’s Storm Prediction Center until 11 pm for Chicago and its south and southeast suburbs—including ALL of northwest Indiana. Counties in Illinois under the watch are Cook, Will, DuPage, Kankakee and Lake. Another tornado watch covers Wisconsin until 10 pm—from the Illinois/Wisconsin border northward. The Chicago area is being raked by powerful non-thunderstorm winds within the “dry slot” of a huge autumn storm. The dry slot is an area of large scale atmospheric subsidence, limited cloud cover and strong winds directly beneath the strongest winds of the jet stream. It is most often several hundred miles across and creates the indentation in huge storm’s cloud cover as viewed from space, lending storms the “comma-shaped” appearance we often refer to on our television weather programs when we display satellite movies. Powerful non-thunderstorm winds have been raking the Chicago area beneath this dry slot and have been clocked by WeatherBug sensors since 2 pm at 53 mph on Chicago’s West Side at Tonti Elementary School, 48 mph in west suburban Aurora and Lombard, 47 mph at Sugar Grove and 45 mph at Elburn.

The Chicago area continues under a severe weather risk, though the storms are likely to be selective, affecting only portions of the metro area. Storms have been actively developing across southern Wisconsin within the past hour (Note: This update is being filed at 3:30 pm Thursday afternoon). Thunderstorms rarely affect a region as large as the Chicago metropolitan area uniformly and the weather situation today will be no exception. What continues to concern us is the POTENTIAL for the development of fast-moving, north-northeastwardbound t-storms over at least SECTIONS of the metro area. Satellite imagery shows a field of enhanced cumulus clouds extending from central Illinois northward into the northeast quarter of the state and into Wisconsin. This corresponds with a region of varied wind speeds at jet stream level—what is known as a “shear-zone”. There, air parcels slow as they depart the region of strongest winds aloft— which encourages air to ascend, a development which enhances cloud development. Allowed to proceed, this cloud development can go on to produce showers and thunderstorms. Wisconsin and areas east may be particularly prone to t-storm development the remainder of the afternoon and early evening, given the presence of particularly “unstable” air there----air which cools faster than usual with height.

Several computer models area are hinting an upper disturbance is to swing northward into Chicago and/or its south and southeast (Indiana) suburbs later today and this evening---about the time these enhanced cumulus clouds reach the metro area. This may enhance cloud development and help initiate the formation of at least some scattered showers or t-storms, which would ascend into a band of powerful steering winds and therefore move at speeds of as much as 50 mph. Especially fast-moving storms, in combination with the normal flow of air out of thunderstorms often become capable of damaging wind production and of spawning microbursts. Not all parts of the Chicago area are likely to see severe weather and the most widespread severe weather is likely to be to our east in Indiana and Michigan. But, given the presence of such strong winds through the atmosphere today, any thunderstorm has a better than usual chance of producing strong gusts beyond the powerful non-thunderstorm wind gusts already occurring.

Ultimately, these storms—expected to selectively affect sections of the metro area—are likely to assemble into a more solid line/band of storms as they proceed eastward into Indiana and Michigan. The arrival of cooler air beyond 10 pm makes that the most likely time beyond which any threat of severe weather in the Chicago area ends.

Tom Skilling

WGN-TV Chief Meteorologist

Lines of powerful thunderstorms, which appeared in the ominous bow shaped configuration on Doppler radars across the Plains, wreaked havoc Wednesday, injuring scores and knocking out power to entire communities. A dozen twisters had been tallied by NOAA’s Storm Prediction Center late Wednesday evening among the more than 138 reports of severe weather.
In Oklahoma, 63 m.p.h. winds collapsed a tent injuring 40 in Tulsa, and rescuers in Woodall worked to free residents trapped by downed powerlines.
A late season severe weather outbreak threatens Chicago with high winds after a night of thundery downpours and could spawn an outbreak of afternoon t-storms capable of generating microbursts and even twisters over at least sections of the Chicago area. Since 1950, October has hosted only 12% of this area’s severe thunderstorms and tornadoes.

--By Tom Skilling, WGN-TV Chief Meteorologist

Wednesday’s mixed sunshine comes just a day after the area’s far western suburbs were hit with 2”+ rains—the biggest in over 7 weeks. It may literally be the calm before the storm. Computer models project a rapidly intensifying low pressure system is to assemble over the Plains. Air drawn aloft into a powerful jet stream leads to strengthening southerly winds which by Thursday are to be stacked vertically tens of thousands of feet through the atmosphere above Chicago. The howling flow—whistling through Chicago airspace at 60+ m.p.h. only 2,000 ft. above ground—sweeps 70°+ warmth and moist 65°+ dew point air into the area and is likely to feed waves of showers and t-storms. It’s beyond that point at which there is the greatest concern for severe weather.
Only 12% of the tornadoes and severe t-storms here since 1950 have occurred in autumn months. Thursday’s weather will have to be monitored.
--By Tom Skilling, WGN-TV Chief Meteorologist

The chill which hit late last week—the first extended spell of cool weather this autumn—cleared the Chicago area Monday allowing temps to surge into the 70s—levels to which they’ll return Wednesday, Thursday and again Sunday. Monday’s 74° at O’Hare and 77° at Midway marked the ninth time this month the mercury has reached or exceeded 70°-—more than the 137 year average of eight 70s in a full October. By comparison, half that number-—only five 70s—had occurred last year through October 16. The first half of the month is 10.3° warmer than the same period a year ago.
The warmth is just part of an autumn which has been extraordinarily dry. It’s allowed farmers to proceed with this fall’s harvest ahead of schedule. Veteran Will County farmer John Hazzard reports that he was able to bring in nearly 200 bushels per acre. That’s far more than the usual 160-180 bushels per acre. Good weather, John reports, went a long way toward making it happen.
--By Tom Skilling, WGN-TV Chief Meteorologist

These beautiful orange and yellow hues preceded Monday’s sunrise captured in these photos near Hobart, Indiana by Amanda Pickett, who’s always beautiful work has graced our weather blog in the past. Thanks Amada and Jim for sharing these beautiful shots with us!

-Tom Skilling

Photos courtesy: Amanda, Pickett

After four cloudy and chilly days with highs in the 50s, the mercury finally broke 60 degrees in the city Sunday, while readings in the south suburbs surged into the lower 70s. Although this week's highs will fall far short of the unseasonable 80-degree-plus warmth featured in October's opening days, a preponderance of southerly winds should keep this week's maximums in the 60s and 70s, with most days at levels substantially above the typical mid-October highs in the lower 60s.
The week should also feature much-needed rainfall. Due to lackluster precipitation since late August, Chicago area soils are drying out, and moisture replenishment would be welcome before cold weather sets in. With frequent weather systems slated to pass through the region this week, the potential for significant rainfall is greater than it has been for quite a while. Sunday's rain was heaviest across north portions of the metro area. Heavier totals included 0.39" at Waukegan and Vernon Hills.
--By Steve Kahn, WGN Weather Center Meteorologist

The recent string of cloudy and chilly days following this October’s unseasonably warm open was a reality check for many Chicagoans, reminding them that the seasonal transition into winter is well under way. Chicago is entering the historical window for this area’s growing-season-ending freezes and is only a little more than two weeks away from the Oct. 30 average date of first snow flurries.
However, Chicago’s “fall into winter” will be placed on hold again in the upcoming week as temperatures are expected to rebound to quite mild levels for the season, reaching the lower 70s on at least two occasions.
The warmth will be accompanied by a noticeable increase in humidity and raise the specter of several periods of showers and t-storms that could bring some welcome rainfall to an increasingly parched landscape. Rain has been sparse here since the deluges of August, making this fall the 16th driest here since 1871.
--By Steve Kahn, WGN Weather Center Meteorologist

Temperatures rebound a bit Saturday and Sunday to more typical mid-October levels before surging into the 70s for a day on Monday. Despite that predicted early week temperature spike, none of Chicago's high temperatures over the coming week are predicted to come anywhere close to the 87 degree highs recorded last Saturday and Sunday.
Temperatures this weekend will run 25 degrees cooler than the same period a week ago. It's a stunning change and one which won't be lost on area residents.
Meteorological Fall 2007 is now six weeks old, and it remains one of the area's warmest and driest of the past 137 years. Temperatures since Sept. 1 are running 4 degrees warmer than the city's long-term average since 1871.
Rainfall since Sept. 1 is more than a half a foot (6.20") below the same period a year ago, and measurable rain has fallen in Chicago on eight days -- far less than the 13 considered normal by this date.
--By Tom Skilling, WGN-TV Chief Meteorologist
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Chicagoans, who until Wednesday had experienced 23 consecutive days of above normal temperatures, shiver through a third day of 50s Friday. Though the chill is more typical of November than mid-October, it pales in comparison to conditions a year ago when the high struggled to reach 39° and the area was hit by its first measurable snow of the season—0.3” of it.
Though weather records indicate the first three-day string of 50s has historically held off another week, chilly temps aren’t a novelty this early in autumn. Back-to-back highs of 54° or lower—similar to those observed here Wednesday and Thursday—have occurred in 17 of the past 48 years.
Cool as the current air mass is, frost is far from a certainty over much of the metro area given the expectation of high clouds Friday night. NW suburban areas appear at greatest risk for any frost.
-By Tom Skilling, WGN-TV Chief Meteorologist

Autumn’s chilliest air, which only days ago roamed Canada’s partially snow-covered tundra 1,700 miles to the north, delivers a second and third day of November-level 50s here Thursday and Friday. The chill, interacting with Lake Michigan’s comparatively warm waters, activated lake-effect rain showers in western Michigan and northeast Wisconsin Wednesday—rains which have shifted overnight into Indiana. Projected winds suggest those rain showers may end up swiping sections of extreme northeast Illinois Thursday—in particular eastern Lake and Cook Counties. But it’s northwest Indiana which is the target of the heaviest, most prolonged lake rains. Several computer forecast models, which aid forecasters in predicting small scale weather features, indicate some 0.50"+ rain totals are possible in Porter and LaPorte Counties before the lake-effect set-up breaks down Friday morning.
--By Tom Skilling, WGN-TV Chief Meteorologist

Wednesday’s blustery winds, combined with the chilliest temperatures since last April, are likely to jar many Chicagoans. The cool air arrives on the heels of one of the warmest October opens on the books. A buckling jet stream, the product of the northward flood of mild air ahead of a powerful landfalling Pacific storm, has developed a ridge aloft. Steering winds riding up and over that ridge have tapped the pool of chilly air collecting over northern Canada’s increasingly snow- covered tundra, forcing it south into the Midwest.
Wednesday’s predicted 53° high—a reading more typical of early November than Oct. 10—represents this area’s biggest three-day October high temperature plunge in 10 years. It was only Monday that readings here surged to 87°. Not since readings tumbled from 82° to 49° in Chicago between Oct. 12-14, 1997 have daytime temps here lost so much ground so quickly.

-By Tom Skilling, WGN-TV Chief Meteorologist

WGN-Weather Center intern Meredith Garofalo took this picture at Jacobs Field, home of the 2007 AL Central Division Champs during the first round of playoffs. Weather was not a normal fall day as partly cloudy skies prevailed with temps in the upper 80's.
Thanks Meredith!

Photo courtesy: Meredith Garofalo

If you are among the Chicagoans who suspect October’s unseasonable warmth has been unusual, new statistics back your assertion. While O’Hare’s 70.3° average temperature the opening eight days of October ranks third warmest since official records began here, Midway Airport’s 72.7° average is even more impressive. Not only does it illustrate the so-called urban heat island effect—the reading is 2.4° warmer over the same period than at O’Hare—it’s the South Side site’s warmest Oct. 1-8 since weather observations began there in 1928.
Monday’s 87° at O’Hare fell just 1° short of the day’s 1997 record. The warmth was part of an air mass which led to record breaking highs across sections of 17 states from Illinois to Washington, D.C. The 91° high at Indianapolis was the city’s warmest ever in October.
The National Weather Service-Chicago thanks the 1,200 visitors who turned out for Saturday’s Open House.
--By Tom Skilling, WGN-TV Chief Meteorologist

I’ve just returned from southern Alaska and wanted to share some photos I snapped over this weekend (October 6-7) of this year’s fall colors. Some of the images you see here were taken along the New Seward Highway which parallels the Turnagain Arm between Anchorage and Girdwood—a community 36 miles southeast of Anchorage. The region features a mix of spruce and deciduous trees. It’s the deciduous trees which change color in autumn. Given the species of trees there, fall colors feature vivid yellow and orange colors rather than the yellow, orange and red mix which occurs here in the Chicago metro area. I can tell you this year’s display, which is peaking in the area from Anchorage southward, is nothing short of spectacular.

“Termination dust”, the term used to cover the first snow cover of the cold season, is creeping down the mountains as snow levels and temperatures in the region drop. Interior and north Alaskan temperatures have fallen to single digits with increasing regularity in the past week and snow now dusts or covers the ground in much of the state’s interior. Note: Much of the Chicago area is two to three weeks from its peak autumn colors while fall colors are peaking (or in spots have just peaked) across northern Wisconsin and are on the verge of peaking in the southern third of the state.

-Tom Skilling

Photo Courtesy: Tom Skilling!

The Oct. 7 record high of 86 degrees set 60 years ago in Chicago was exceeded yesterday by a degree at O'Hare Airport and by at least that number at many other locations around the metro area. The record hot and humid conditions unfortunately coincided with the 30th running of the LaSalle Bank Chicago Marathon.
While southerly winds, warmth and humidity again greet Chicagoans today, increasing cloudiness, showers, and a wind shift to the west later this afternoon will signal the beginning of a change to much more fall-like weather. Temperatures will slowly drop the following 24 hours with the coldest air scheduled to hit northeast Illinois Wednesday. Highs Wednesday will struggle to hit the mid 50s -- more than 30 degrees cooler than the highs experienced over this past weekend. The remainder of the week will average about 3 degrees below normal. Longer-range projections indicate warmer-than-normal readings the following week.
--By Paul Dailey, WGN Weather Center Meteorologist

It depends upon how much cloudiness develops, but with enough sunshine Sunday’s high temperature could reach into the upper 80s, exceeding the existing record 86° high set on this date back in 1947. Even without the record the day will be very warm and humid, with the morning temperatures just prior to the start of the LaSalle Bank Chicago Marathon expected to be in the lower 70s. If that is the case, another record—this one set ninety-three years ago—will be broken. The record high low temperature for October 7th was 66 degrees set back in 1914. Clouds will increase from the west, and the approach of a cold front should trigger showers and thunderstorms later Monday. Colder Canadian high pressure will move into the Midwest Tuesday with the core of coldest air over NE Illinois Wednesday and Thursday. A drop of some 30° in high temperatures from today’s upper 80s to Wednesday’s forecast mid 50s is possible.
--By Paul Dailey, WGN Weather Center Meteorologist

Friday's high temperatures ran in the mid 80s around the metro area except for cooler conditions along the Lake Michigan shoreline. If highs reach the upper 80s both today and Sunday as forecast, readings will average over 20 degrees above normal. This weekend would go down as the warmest in eight weeks -- dating back to the weekend of Aug. 11-12 -- and it would be the 4th warmest weekend of the entire year. This warmth is so unusual that the Cubs are actually coming back to continue the playoffs in a warmer location: Phoenix is expecting highs only in the low to mid 80s.
Sunday's 30th annual LaSalle Bank Chicago Marathon will most likely be run under the warmest conditions ever with runners advised to guard against potential overheating, cramping or other heat-related maladies. A cold frontal passage Monday will usher in much cooler air with highs expected to be 20 to 25 degrees cooler for the rest of the week.
--By Paul Dailey, WGN Weather Center Meteorologist

As south winds flowing up the back side of blocking high pressure along the east coast bring unseasonable warmth to the mid sections of the country, cold air wrapping around a deep low pressure pattern unleashes heavy snows over portions of the the Rockies. Six to 12-inch snows are forecast for Glacier Park in NW Montana and high elevations of western Wyoming today. July-like heat and humidity will build over northeast Illinois this weekend with Saturday’s Wrigley Field game time temperatures for the Cub-Diamondback playoff only some 5° lower than the 90° readings experienced by those baseball clubs in Phoenix Wednesday and Thursday. Sunday’s 30th running of the LaSalle Bank Chicago Marathon may be the warmest ever with 8 a.m. CDT starting time temperatures forecast to be 5° above the normal high temperature for that date. Significant cooling is not expected before next Tuesday.
--By Paul Dailey, WGN Weather Center Meteorologist

Chicago lies in the heart of a corridor of strengthening southerly wind flow, surface and aloft, that is set to deliver temperatures more typical of July than October. Today’s expected maximum temperature of 83º brings the city’s year-to-date total of 80º+ days to 97, with four additional 80º+ days expected. The all-time record is 103 days (2005).
Lost in the shuffle of Chicago’s spell of unseasonably warm afternoon temperatures is this fact: It’s going to be uncomfortably warm—and humid —at night as well. An examination of 48 years (1959-2006) of Chicago’s temperature records as measured at O’Hare reveals that overnight minimum temperatures have managed to remain above 69º on only two occasions this late in the season: 70º on Oct. 21, 1979, and 71º on Oct. 4, 2005. If forecasts verify, that two-day tally will double with 70º expected Friday night and 71º Saturday night.
--By Richard Koeneman, WGN Weather Center Meteorologist

Today's readings in the middle 70s (8 degrees above normal) are easy enough to take in mid autumn -- but break out the ice cubes and fire up the air conditioner because real warmth arrives tomorrow, then grows even stronger on Friday and Saturday.
Before cooler air finally arrives early next week, Chicago's afternoon temperatures are forecast to climb above 80 degrees for four consecutive days. That won't challenge the October record (eight consecutive 80-degree-plus days, Oct. 15-22, 1953), but it's a feat that has occurred here only 12 times in 79 years.
Oct. 3 is an auspicious day in weather history. Bagdad, Calif., is a settlement just to the south of Death Valley. A little bit of rain fell at Bagdad on Oct. 2, 1912, and the 3rd was dry -- and thus began the longest totally rain-free period ever recorded in the United States. Absolutely no rain fell there for 767 days -- slightly over two years -- beginning on today's date in 1912.
--By Richard Koeneman, WGN Weather Center Meteorologist

The weather forecasts continue to offer conditions more typical of August than early October: temperatures in the 70s and 80s, humid and gusty south winds and several thunderstorms in the mix.
The atmosphere is primed to generate strong thunderstorms this afternoon in the Great Plains, and the somewhat weakened remnants of those storms are forecast to sweep into Chicago, arriving here late tonight. They are likely to be copious rain producers, and one-inch rain totals are not out of the question. Beyond that, warm and humid air persists through midweek.
The tropics, currently rather quiet, might not remain that way much longer. The National Hurricane Center continues to monitor an area of low pressure between Florida and the Bahamas.
This system has some potential for tropical or subtropical storm development in the next couple of days as it moves generally to the west at 10 to 15 m.p.h.
--By Richard Koeneman, WGN Weather Center Meteorologist