Severe Thunderstorm Warning 28, NWS Chicago, IL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO IL
600 PM CDT SAT MAY 10 2003

AVIATION DISCUSSION FOR 00Z TAFS...
SFC LOW FAR S CNTRL IA TO CONT RAPID DEEPENING TONIGHT AS IT MOVS TO
SW WI BY 06Z AND TO NE WI BY 12Z WITH UPR LOW CLOSING OFF OVER NRN
NEB/SE SD AS 120KY JET PUNCHES NEWRD INTO UPER MIDWEST. SQ LN
RAPIDLY FILLING FM SE IA TO NW AR AHEAD OF CDFNT. CELLS MOVG NE AT
60KT WITH LN MOVG E AT 40KT. LN ARRIVAL TIME STILL EXPECTED 01-02Z
RFD VC...02-03Z CHI VC...03-04Z GYY VC WITH VERY UNSTABLE AIRMASS IN
QUICKLY SPREADING FM CNTRL INTO NRN IL. CONT G45KT WITH TSRA GIVEN
MDL FCST OF 40KT WNDS WITHIN 2K FT OF SFC DURG EVE. THIS VERIFYING
WITH WINCHESTER PROFILER MEASURING 30KT AT 750M AGL AT 22Z. BRIEF
CLRG WITH CFP THEN MVFR SC DECK RAPIDLY MOVS IN OVRNGT. STG
UNIDIRECTIONAL FLOW TOMORROW...UP TO 50KTS WITHIN 2K FT OF SFC PER
MDL SOUNDINGS...WILL RESULT IN VRY GUSTY WSW WNDS...WITH CHC -SHRA
IN WRAP AROUND MOISTURE.

TRS

DISCUSSION FOR AFTERNOON GRIDS...

HIGH THREAT OF SEVERE WEATHER CONTINUES ACROSS THE FORECAST AREA
THIS AFTERNOON. CLOUD COVER ASSOCIATED WITH EARLIER RW/TRW
DISSPIPATED AROUND NOON ALLOWING STRONG HEATING THROUGH THE COURSE
OF THE AFTERNOON. DEWPOINTS THROUGH SOUTHERN SECTIONS OF AREA HAVE
CLIMBED INTO MIDDLE AND UPPER 60S. AIRMASS IS PRIMED FOR STRONG
FORCING WITH ARRIVAL OF DEEPENING SURFACE LOW NOW AROUND MKC AND
MOVING TO INFLUENCE AREA THIS EVENING. EXPECT ACTIVITY TO BEGIN IN
THE NEXT FEW HOURS.

SURFACE LOW CONTINUES TO DEEPEN AFTER PASSAGE TO THE NORTHEAST LATE
TONIGHT/SUNDAY MORNING. TIGHTENING GRADIENT WILL BRING STRONG WINDS
IN 20 TO 30 MPH RANGE ALONG WITH NOTICEALBLY COOLER AIRMASS.
INSTABILITY SHOWERS IN THE COLD AIR WILL BE LIKELY IN THE NORHTERN
SECTIONS BUT LIMITED TO A CHANCE IN THE SOUTH. WINDS SHOULD STAY AOB
20 MPH UNTIL EARLY MONDAY AS LOW BEGINS TO FILL AND MOVE NORTHEAST
OF GEORGIAN BAY.

SURFACE RIDGE BUILDS ACORSS CENTRAL US THROUGH WENDESDAY WHILE WEAK
SURFACE LOW DEVELOP ON SOUTHER PLAINS AND BRING A CHANCE OF SHOWERS
WED.

.CHI...GALE WARNING SOUTH 2/3 LAKE MICHIGAN SUNDAY AND MONDAY

ILZ003>006-008-010>014-019-020>023-032-033-039-INZ001-002-010-011-019
-111100-

HAZARDOUS WEATHER OUTLOOK...UPDATED...
NATIONAL WEATHER SERVICE CHICAGO IL
815 PM CDT SAT MAY 10 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTH CENTRAL AND NORTHEAST
ILLINOIS...NORTHWEST INDIANA...AND THE ADJACENT WATERS OF LAKE
MICHIGAN.

.DAY ONE... TONIGHT

A TORNADO WATCH IS IN EFFECT UNTIL 200 AM SUNDAY MORNING FOR THE
ENTIRE AREA. TORNADIC STORMS IN WESTERN ILLINOIS ARE SPREADING
NORTHEAST THIS VERY MOMENT. THIS IS A VERY SERIOUS WEATHER SITUATION
THAT IS NOW UNDERWAY.

YOU SHOULD HAVE EMERGENCY PLANS IN PLACE RIGHT NOW IN CASE YOU ARE
IN A TORNADO...SEVERE THUNDERSTORM...OR FLASH FLOOD WARNING.
EMERGENCY MANAGERS SHOULD NOW BE IN PREPARATION FOR SEVERE WEATHER.
LISTEN TO NOAA WEATHER RADIO FROM THE NATIONAL WEATHER SERVICE...
TELEVISION OR RADIO FOR STATEMENTS AND UPDATES.

.DAYS TWO THROUGH SEVEN... SUNDAY THROUGH FRIDAY

STRONG WINDS OF 20 TO 30 MPH WITH HIGHER GUSTS WILL OCCUR MOST OF
THE DAY SUNDAY ACROSS THE ENTIRE REGION.

.SPOTTER INFORMATION STATEMENT...

SPOTTERS ARE NEEDED AT THIS MOMENT UNTIL THE STORMS CLEAR THE AREA
AFTER 2 AM SUNDAY.

&&

           NWS CHICAGO WEBPAGE

    HTTP://WWW.CRH.NOAA.GOV/LOT (LOWER CASE)
OR  HTTP://WEATHER.NOAA.GOV/CHICAGO (LOWER CASE)

BRUMER