Severe Thunderstorm Warning 113, NWS Chicago, IL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO IL
300 PM CDT MON MAY 31 2004

.DISCUSSION...
DEEP H5 LOW OVER THE UPPER LAKES BROUGHT CLOUDY SKIES...SCATTERED
THUNDERSTORMS AND SMALL HAIL TO MOST OF THE FORECAST AREA TODAY.
WITH LOW BEING SLOW TO MOVE EAST OF THE AREA...EXPECT SCENARIO
SOMEWHAT SIMILAR TO TODAY WITH SHOWERS AND SOME THUNDERSTORMS TO
REVELOP AGAIN TUESDAY AS WAVES ROTATE AROUND/THROUGH TROUGH.
COMBINATION OF DIURNAL HEATING AND COLD TEMPS ALOFT PRESENT THE
POSSIBILITY OF PEA HAIL ALSO.

SOME DIFFERENCES ON WHEN UPPER LOW IS EAST OF AREA WITH GFS BEING
ODD MAN OUT. FORECASTS REFLECT ETA/NGM SOLUTIONS WITH CLOSED LOW
NORTH OF LAKE HURON WEDNESDAY MORNING AND SURFACE FROPA THROUGH
NORTHEAST ILLINOIS EARLY WEDNESDAY. HI AMP RIDGE BUILD OVER CENTRAL
US AFTER TROUGH MOVES EAST THAT SHOULD FINALLY BRING SOME DRY WX TO
THE AREA. SURFACE RIDGE BUILDS OVER THE UPPER LAKES WEDNESDAY
THROUGH SATURDAY. NEXT WEATHER APPEARS LATE SATRUDAY INTO
SUNDAY/MONDAY AS WAVES IN H5 FLOW PASESES ACROSS AREA.

&&

.AVIATION...
WITH VORT MAX CURRENTLY ROTATING NEWRD INTO FAR SERN WI...NUMBER OF
SHRA/TSRA SHUD CONT TO DEC DURG EARLY PART OF FCST PD.  SUBSIDENCE
IN WAKE OF VORT AND LACK OF SFC FOCUS TO LIMIT RENEWED DVLPMNT BUT
GIVEN STEEP LAPSE RATES INDICATED BY FCST SOUNDINGS DUE SFC HEATING
AND COOL MID LVLS...STIL LOW PROB OF OCCURENCE THRU LATE
AFTERNOON/EARLY EVE BUT NO MENTION IN TAFS BEYOND 20Z DUE
RESTRICTION ON PROB GROUPS FIRST 9HRS. STEEP LAPSE RATES ALSO TO
ALLOW STGR WND ALFT TO MIX DOWN WITH GUSTY SFC WNDS EXPECTED TIL
NEAR SUNSET. WRAP AROUND MOISTURE TO SPREAD INTO NRN IL OVRNGT AS
UPR LOW ON ND/MN BORDER DROPS SEWRD.

TRS

&&

.LOT...WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LK MI...NONE.

IMPORTANT NOTICE...EFFECTIVE JUNE 8...THE AWIPS IDENTIFIER FOR
THIS PRODUCT WILL CHANGE FROM CHIAFDCHI TO CHIAFDLOT. THE WMO
HEADER FXUS63 KLOT WILL NOT CHANGE.

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE CHICAGO IL
600 AM CDT MON MAY 31 2004

ILZ003>006-008-010>014-019>022-023-032-033-039-INZ001-002-010-011-019
-011100-
WINNEBAGO-BOONE-MCHENRY-LAKE IL-OGLE-LEE-DE KALB-KANE-DU PAGE-COOK-
LA SALLE-KENDALL-GRUNDY-WILL-KANKAKEE-LIVINGSTON-IROQUOIS-FORD-
LAKE IN-PORTER-NEWTON-JASPER-BENTON-
600 AM CDT MON MAY 31 2004

THIS PORTION OF THE HAZARDOUS WEATHER OUTLOOK IS FOR NORTH CENTRAL
AND NORTHEAST ILLINOIS...AND NORTHWEST INDIANA.

.DAY ONE...TODAY AND TONIGHT

THERE WILL BE A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS NORTHEAST
ILLINOIS AND NORTHWEST INDIANA TODAY. A POOL OF COLD AIR ALOFT WILL
MOVE OVER THE REGION AND DESTABILIZED THE ATMOSPHERE THIS AFTERNOON.
THIS WILL PROVIDE ENOUGH INSTABILITY TO SET OFF SCATTERED SHOWERS
AND THUNDERSTORMS. SOME OF THE THUNDERSTORMS MAY PRODUCE LARGE HAIL
AND GUSTS OF WIND UP TO 58 MPH.

THERE ARE RIVERS IN FLOOD. HEAVY RAIN FELL ACROSS MOST OF THE REGION
SUNDAY. THE RIVERS ARE THE FOX...DES PLAINES...KISHWAUKEE...ROCK...
ILLINOIS AND VERMILION RIVERS. SEE FLOOD STATEMENTS AND FLOOD
WARNINGS FOR ADDITIONAL DETAILS.

.DAYS TWO THROUGH SEVEN... TUESDAY THROUGH SUNDAY

THERE WILL BE CHANCE OF THUNDERSTORMS TUESDAY AND WEDNESDAY AS THE
LARGE UPPER AIR DISTURBANCE MOVES SLOWLY ACROSS THE REGION.

.SPOTTER INFORMATION STATEMENT...

SPOTTER SHOULD BE ALERT TODAY FOR THUNDERSTORMS THAT MAY BECOME
SEVERE.

&&

COMPLETE FORECAST INFORMATION IS AVAILABLE ON THE
NWS CHICAGO WEBPAGE: WWW.CRH.NOAA.GOV/LOT (LOWER CASE)

LMZ740>746-766-011100-
WINTHROP HARBOR IL TO NEW BUFFALO MI-
LAKE MICHIGAN-
600 AM CDT MON MAY 31 2004

THIS PORTION OF THE HAZARDOUS WEATHER OUTLOOK IS FOR THE ILLINOIS
AND INDIANA WATERS OF LAKE MICHIGAN.

.DAY ONE...TODAY AND TONIGHT

SCATTERED THUNDERSTORMS MAY OCCUR TODAY. SOME ISOLATED SEVERE
THUNDERSTORMS ARE POSSIBLE.

.DAYS TWO THROUGH SEVEN... MONDAY THROUGH SATURDAY

SCATTERED THUNDERSTORMS ARE POSSIBLE TUESDAY AND WEDNESDAY.

&&

COMPLETE FORECAST INFORMATION IS AVAILABLE ON THE
NWS CHICAGO WEBPAGE: WWW.CRH.NOAA.GOV/LOT (LOWER CASE)