WGN Weather Center Blog

Just days after a thorough soaking by the remnants of Gustav, more rain is headed for
Chicago. Some light showers may develop Sunday, but the city is in line for another
round of significant shower and thunderstorm activity Monday and Monday night as a
cold front pushes through the area. Chilly weather will follow, and low temperatures
may dip below 50 degrees both Tuesday and Wednesday mornings for the first time
since May 29, when the mercury dipped to 42 degrees.

A brief warm-up will boost readings back to around 80 by Thursday, but another cold
front will drop temperatures back to around 70 by next weekend.

HANNA EUROPE-BOUND AS DANGEROUS HURRICANE IKE MARCHES TOWARD FLORIDA AND THE GULF

Tropical Storm Hanna brushed the Eastern Seaboard with gusty winds and heavy rainfall
Saturday. After speeding through the Canadian Maritimes Sunday, it will make a beeline
for the British Isles. Meanwhile, Ike, now a Category 4 hurricane packing top winds of
135 m.p.h., appears headed on a path that will threaten Cuba and southern Florida
before entering the Gulf of Mexico by midweek.

--By Steve Kahn, WGN Weather Center Meteorologist

Posted by wgnweather at 8:11 PM | Permalink

Posted by wgnweather at 8:06 PM | Permalink | TrackBacks (0)

Dear Tom,
Please tell me a few things about the “eye” of a hurricane.
-Leecie Pearce, Delavan, Wis.

Dear Leecie,

The “eye” is a roughly circular area of rather quiet weather found at the center of a
hurricane. Eyes generally are 20 to 40 miles across, but they range in size from about 5
miles to (rarely) more than 120 miles. Winds are light or calm at the very center of an
eye, but strong winds can sometimes extend into its periphery. There is little or no rain,
and sometimes the sky is partially clear, but the eye is surrounded by a circular ring of
towering cumulonimbus clouds— the “eyewall”—that often extends upward more than
30,000 feet. A hurricane’s lowest air pressure is found in its eye, and its highest winds
occur in the eyewall. Temperatures in the eye are only slightly warmer than in the
surrounding storm.

Posted by wgnweather at 7:40 PM | Permalink | TrackBacks (0)

The cool air mass responsible for Chicago's first back-to-back 60s -- on Thursday and
Friday at Midway Airport -- in nearly 11 years during September's opening five days
dominates this weekend. While both Saturday and Sunday a week ago produced highs
of 90 degrees, peak readings Saturday and Sunday will average 20 degrees cooler.
Those are levels modestly below normal by early September standards. Weak
disturbances embedded in the jet stream will produce several periods in which showers
may flare.
Final rain tallies from Gustav's blustery remnants Thursday approached 3 inches. The
National Weather Service confirms damage in Wheatfield in northwest Indiana was
produced by winds that were part of an EF1 twister that hit the community around 5:30
p.m.

DANGEROUS IKE MAY THREATEN FLORIDA AND ENTER THE GULF OF MEXICO
While Tropical Storm Hanna rapidly spins up the Eastern Seaboard, all eyes are turning
to Hurricane Ike, currently heading toward the Bahamas.
Ike, a Category 3 hurricane packing top winds of 115 m.p.h. Friday night, is expected to
grow even stronger as it steadily churns westward toward Florida and the Gulf of
Mexico.
--Tom Skilling, Chief Meteorologist, WGN-TV/Chicago Tribune

Posted by wgnweather at 11:10 PM | Permalink

Posted by wgnweather at 11:02 PM | Permalink

Dear Tom,
Why does the Atlantic Ocean get more hurricane activity than the Pacific?
Scott Okun
Dear Scott,
With all of the recent hurricane activity in the Atlantic Basin it may seem
that way, but the truth is the Pacific wins the tropical cyclone competition
hands down. The Atlantic Basin averages about 10 named storms each year
while the Eastern Pacific typically logs 16 storms. Because of the potential
threat to the United States, the Atlantic storms get a lot of publicity
while most of the eastern Pacific storms get little press as they pose a
threat only to shipping. In addition, each year the Northwest Pacific
averages 20 typhoons and the Southwest Pacific waters generate as many as 10
hurricanes. In contrast, because of colder water and strong winds aloft
there are almost no hurricanes in the South Atlantic.

Posted by wgnweather at 10:43 PM | Permalink

Thanks for joining us for this Friday, weekend edition of Before the Forecast! And a special thanks to Kim, our intern, for working hard to bring you today's webcast!

For complete weather information, tune in to WGN News at 9pm and wgntv.com for Tom Skilling's Full and 7-day forecasts.

Tune in tomorrow for another edition of Before the Forecast, and as always continue
to watch WGN for more coverage: Morning, Noon & Nine.

Posted by Brandi Larsen at 10:14 AM | Permalink | TrackBacks (0)

Gustav's blustery remnants lived up to the advance billing Thursday, dousing the
Chicago area with its heaviest official rain in more than five years. By evening,
preliminary totals at the Whitney Young High School Weather Bug sensor had reached
4.12 inches with rain still falling. Other reports included 4.06 inches at Justice, 3.76
inches at Palatine, 3.67 inches at Wilmette, 3.62 inches at Orland Park and 3.51 inches
at Lake Zurich. A rainfall of 4.50 inches hit Downstate at London Mills -- located
between Peoria and the Mississippi River. It marked the first time in three years that the
remnants of a landfalling Gulf Coast hurricane reached Chicago. Hurricane's Rita's
remnants were the last to occur here in 2005.

POWERHOUSE HURRICANE IKE CHURNS TOWARD BAHAMAS; FLORIDIANS
UNEASY

Ragged Tropical Storm Hanna is headed for the Carolinas -- but more ominously,
powerhouse Category 4-intensity (135 m.p.h. peak winds) Hurricane Ike appears
headed for the Bahamas. Some computer models indicate Florida may later be a target
which has residents there on edge. The storm is still five days aways and much can
change. But it's a situation that warrants close observation.

--Tom Skilling, Chief Meteorologist, WGN-TV/Chicago Tribune

Posted by wgnweather at 10:20 PM | Permalink

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Dear Tom,

I lived in Liberia for seven years and we experienced dust storms called harmattans. Do
these winds eventually cause the hurricanes that reach the U.S.
-Patrick McKeen Buffalo Grove

Dear Patrick,

Hurricanes that affect United States often do develop from westward-moving
disturbances the move out of Africa into the Atlantic near the Cape Verde Islands.
However, these dust storms are not associated with hurricanes. Instead, the harmattan
winds are dry, dust-carrying winds from the northeast or east that blow in West Africa
especially from late November until mid-March. In summer, an onshore flow called the
southwest monsoon brings cooler air inland to West Africa, undercutting the
harmattan. The harmattan continue to blow aloft in a layer from about 3,000-6000 feet
carrying dust out into the Atlantic.

Posted by wgnweather at 9:44 PM | Permalink