| Home | News | Weather | Programming | Sports | Station Info | Employment | Contact Us | Contests |
|
|
« August 2007 | Main | October 2007 »
In yet another demonstration of the truism that the weather does not read the calendar, Chicagoans will enjoy another week of summer temperatures in the autumn. The average of daily high and low temperatures from today through Oct. 7 is expected to be 68 degrees, and that is 11 degrees above the climatological normal for that period. The city's daily highs are forecast to reach or exceed 80 degrees on four of the next six days -- a significant contrast to the long-term historical expectation that only one day in eight climbs to that level in early October. Thunderstorms, too, will be rumbling across the city area this week with a frequency more typical of July than October. A parade of disturbances sweeping across the Upper Midwest (similar to the system that spawned Sunday night's storms) will trigger storms about every three days -- late Tuesday into Wednesday and again late Saturday.
--By Richard Koeneman, WGN Weather Center Meteorologist
At midnight tonight, September enters the record books as one of Chicago's warmest, sunniest, and driest in recent years. And summer refuses to let go, because October will begin where September left off. Afternoon temperatures in the 70s and 80s are projected right through the upcoming week.
Computer models indicate the jet stream and major storm track will remain well to the north, approximately along the Canadian border, and southerly wind flow will be the dominant factor in Midwest weather for several days. That keeps Chicago's afternoon high temperatures 7-16 degrees above the upper 60s that are typical at this time of the year.
September's exceptionally sparse precipitation totaled barely more than an inch -- only one-third of normal -- but that might improve in October. Several opportunities for showers and thunderstorms may present themselves, especially with a pattern change 6-8 days from now.
--By Richard Koeneman, WGN Weather Center Meteorologist
Chicago weather historian Frank Wachowski provides these preliminary weather statistics for September 2007: With 76 percent of possible sunshine (versus a normal of 62 percent), it will enter the record books as Chicago's sunniest month in three years (sunniest since, coincidentally, September of 2004, which registered 90 percent of possible sun).
With an average temperature of 68.2 degrees (4.4 degrees above normal), this becomes the fifth warmest September since temperature observations began at O'Hare Airport in 1959.
Finally, September delivered 1.09 inches of rain -- only one-third of the normal monthly total of 3.27 inches.
And the warm temperature regime continues. Chicago's afternoon readings are forecast to reach or exceed 80 degrees on four of the next six days, but the climatological expectation in early October is only one day out of six.
A few thunderstorms are possible late Sunday and again late Tuesday.
--By Richard Koeneman, WGN Weather Center Meteorologist
An enduring characteristic of Chicago’s vigorous temperature climate is its tendency to reach for the extremes, and that’s what lies immediately ahead. It will be a pleasurable experience this time around, because unseasonable daytime warmth is anticipated.
Strengthening southwesterly winds, surface and aloft, will dominate Chicago’s weather through most of the upcoming week. Today’s high temperature in the lower 70s is likely to be the coolest day by far of the next six. Expected high temperatures averaged over the week beginning today (Sept. 28-Oct. 4) is 79º, almost 11º above normal, and a temperature level that ranks among the five warmest such periods in 136 years of Chicago temperature history.
Those expected daily temps won’t challenge daily record highs—those are in the 90s—but the persistent warmth will take the week’s average high temperature into near-record territory.
--By Richard Koeneman, WGN Weather Center Meteorologist
Meteorologists love to describe temperatures in terms of “departures from normal.” They will say, “Yesterday’s high was 69º, and that was one degree below normal.” (And that actually was Tuesday’s departure from normal, as officially measured at O’Hare.)
What’s left unsaid, however, is that a “normal” temperature is the 30-year average derived from the period 1971-2000, and that it is quite unusual for a day’s temperature to be right at “normal.” It’s even more unusual for two days to run at or near normal, but that is the pattern in which Chicago will find itself today and again Friday.
Chicago’s temps usually spend most of their time bouncing from well above normal to well below, and back again. Today’s “near normal” pattern breaks down over the weekend, when a warming trend sends readings to the upper 70s (9º above normal) and into the lower 80s (14º above) by this coming Tuesday.
--By Richard Koeneman, WGN Weather Center Meteorologist
Severe thunderstorms blasted across metropolitan Chicago Tuesday afternoon and evening, but they were a hit-or-miss affair. Damaging winds and blinding rains struck a few locations, whereas residents in other spots bypassed by the storms were left wondering what the fuss was all about.
High winds left several buildings in Elgin (35 miles west of the Loop) with structural damage, and Gary, Ind., reported a gust to 60 m.p.h. Other locations experienced only moderate winds. Rainfall also varied widely, and that is typical of thunderstorm precipitation. West suburban Oak Brook recorded 1.13 inches of rain in 20 minutes around 3 p.m., but a sprinkle barely dampened the ground at Midway Airport.
Tuesday’s strong thunderstorms and 85° temperatures preceded the arrival of much cooler Canadian air that will dominate the local weather scene for several days.
--By Richard Koeneman, WGN Weather Center Meteorologist
Photo by Scott Korogodsky
Thanks to Scott Korogodsky for taking this great shot of a rainbow over Dolphin Stadium in Miami very early in tonight's game between the Cubs and the Florida Marlins.
It’s an ideal brew for strong thunderstorms across the Midwest: A vigorous jet stream aloft and a strong cold front advancing into warm, humid air. The Storm Prediction Center indicates the possibility of severe t-storms here and elsewhere in the Midwest.
Yesterday’s warmth sent Chicago’s temperature to an official high of 90º at O’Hare (one degree shy of the record for the day) and to 91º at Midway (which established a new, though unofficial, daily record high at that station). Kankakee registered the area’s hot spot, with 95º.
Proving that some good can come from just about any kind of weather, the recent long stretch of dry days has advanced Illinois crop harvests. WGN’s AgriBusiness broadcaster Max Armstrong says the Illinois corn and soybean harvests are running well ahead of normal. However, August’s heavy rains and flooded fields have devastated area pumpkin production.
--By Richard Koeneman, WGN Weather Center Meteorologist
Borne in by gusty southerly winds strong enough to overcome the cooling influence of Lake Michigan, warm air surging across Chicagoland today will send afternoon temperatures well into the upper 80s.
This is the ground-level effect of a powerful jet stream whose 90-m.p.h. winds (at an elevation of 45,000 feet) are blasting in a corridor from Oklahoma to Lake Superior. Chicago's expected high temperature in the upper 80s puts the thermometer within shooting distance of the record high for the date, 91 degrees, registered 116 years ago (1891). The amount of temperature-lowering daytime cloudiness is an important consideration. Gathering afternoon clouds may cap area temperatures in the mid 80s, whereas a sunny afternoon would permit a run at the day's record.
Powerful thunderstorms that rattled across the Northern Plains late Sunday will develop again today, and remnants of those storms arrive here by Tuesday.
--By Richard Koeneman, WGN Weather Center Meteorologist
Geographer Dr. George Kimble once observed that, weatherwise, “September is a month of many virtues and few vices.”
Many Chicagoans might find Kimble’s generalization overly optimistic, but few will contest the splendid weather that the city is experiencing this weekend. Saturday’s sunny sky and temperatures in the 70s as well as Sunday’s readings in the 80s provide a perfect setting for outdoor activities.
However, late September has also delivered genuinely nasty weather in years past in other places. The temperature plunged to -9ºF at Yellowstone National Park on Sept. 24, 1926, and widespread freezing readings caused huge crop losses from Washington to Montana. A rare West Coast hurricane moved onshore south of Los Angeles on Sept. 25, 1939.
Finally, large hail killed several hundred Canada geese in Wisconsin’s Horicon Marsh on Sept. 30, 1993.
--By Richard Koeneman, WGN Weather Center Meteorologist
Chicago area temperatures hit rarified heights Friday afternoon, with most locations recording highs in the upper 80s to lower 90s. Highest readings included 93 degrees at Kankakee and 91 degrees at Northerly Island. Midway's 90 degrees was only the 4th time this figure was reached on Sept. 21 in 80 years of weather records at that site.
However, Chicagoans will experience significantly cooler and less humid conditions today as Canadian high pressure pushes into the area. The impact of this high will be short-lived as it quickly moves east. Strong warming southerly flow up the backside of that high reaches into Illinois Monday. The best chance of thunderstorms next week will most likely be Monday night and Tuesday, preceding and accompanying a vigorous cold front.
Tornadoes were associated with a low pressure system along the northern Gulf Coast Friday night, with heavy rains and flooding expected as it moves into southern Mississippi today.
--By Richard Koeneman, WGN Weather Center Meteorologist
On today’s date, the “Great New England Hurricane of 1938” smashed without warning across a portion of the nation that rarely experiences such storms: New England. The tropical cyclone grazed Cape Hatteras, N.C., about 3 a.m. on Sept. 21 and, from there, Weather Bureau forecasters believed the hurricane was headed northeast into the Atlantic Ocean, as such storms typically do. This was in the days before aircraft reconnaissance, weather radar or satellite surveillance. Unrealized by the forecasters, the hurricane instead accelerated north at 50-60 m.p.h.—the highest forward speed a hurricane has ever attained—and blasted with Category 3 intensity (winds 111-130 m.p.h.) across Long Island, N.Y., and into Rhode Island and surrounding areas by early afternoon. The sun had been shining only two hours earlier. Winds and storm surge claimed nearly 600 lives, and left New England in a shambles.
--By Richard Koeneman, WGN Weather Center Meteorologist
Wednesday marked the seventh time this month temperatures here have surged to 84° or higher. The 84° high at both Midway and O’Hare and the 87° reading at Northerly Island were 29° warmer than the chilly 55° high a year ago. It was so cool in September a year ago, the month’s warmest reading never even reached Wednesday’s levels, peaking just once at 83° on Sept. 8 and reaching or exceeding 80° in 2006 only four times all month! By contrast, there have been eleven 80°+ days this September.
Easterly winds off Lake Michigan lower temperatures Thursday—but only modestly. Strong southerly winds send readings back to the upper 80s Friday.
North Floridians dealt with high winds and waves of heavy rain a third day Wednesday. Rainfall at Daytona Beach had reached 4.21” by late evening—a new record—while Jacksonville Beach’s rain tally since Monday soared to 10.31”.
--By Tom Skilling, WGN-TV Chief Meteorologist
