Special Marine Warning 21, NWS Chicago, IL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO IL
315 PM CDT MON JUN 10 2002

GOING FCST STILL ON TRACK.  LATEST SATLT/RADAR LOOPS SHOW SMALL
CLUSTERS OF TSTMS OVR ENTR RGN.   AMS WILL BE TEMPORARILY
STABILIZED BY PASG OF STGR STMS DUE TO OUTFLOW.  HOWEVER...
OVERALL SYNOPTIC PATN STILL SHOWS BROAD 30 TO 35 KT H85 FLO INTO
RGN WITH PLENTY OF INSTABILITY JUST UPSTREAM.  THEREFORE EXPECT
OTHER TSTM CLUSTERS OVER CNTRL IL TO MIGRATE NWD INTO FA THIS
EVE.  BASED ON THIS AND ONGOING CONVECTION ACRS AREA WILL JUST
GO WITH UNQUALIFIED MENTION OF SCTD TSTMS...MAIN EMPHASIS ON
THIS EVE AS COMBINATION OF LOSS OF DIURNAL HEATING AND PASSAGE
OF S/W NOW MOVG THRU RGN SHUD LIMIT DVLPMT LATER DURG THE NIGHT.

BIG QUESTION DEALS WITH TUES/TUES NGT TIME FRAME.  MODELS HAVE
BEEN SOMEWHAT INCONSISTENT WITH FRONTAL TIMING...BUT SEEM TO BE
ZEROING ON LATE TUES NGT-WED MRNG.  AT ANY RATE EXPECT FRONTAL
ACTIVITY TO BE SAGGING S OF CWA BY NOON WED FOLLOWED BY PARTIAL
CLRG.  WILL GO WITH LIKELY POPS FOR TUES NGT AS PER MAV GUID DUE
TO HIGH DEGREE OF INSTABILITY AHD OF FRONT.  ONLY LIMITING
FACTOR APPEARS TO BE WIND PROFILES AS WK LO LVL RIDGE AXIS JUST
TO SW OF RGN CONTINUES TO BE ADVERTIZED BY MDLS ON TUES AND TUES
NGT.

WILL MAKE LTL CHG TO RMNDR OF FCST AS INSTABILITY SHWRS APPEAR
LIKELY GIVEN AVN FCST SOUNDINGS THUR AFTN AND PROBABLY FRI AFTN
AS WELL.

.CHI...NONE

MERZLOCK

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

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE CHICAGO IL
1200 PM CDT/EST MON JUN 10 2002

FOR NORTH CENTRAL AND NORTHEAST ILLINOIS AND NORTHWEST INDIANA.

NO SEVERE THUNDERSTORMS ARE EXPECTED THIS AFTERNOON OR TONIGHT.

UNSTABLE TROPICAL AIR IN COMBINATION WITH AN UPPER LEVEL DISTURBANCE
OVER THE MIDDLE MISSISSIPPI VALLEY WILL PROMOTE THUNDERSTORM
DEVELOPMENT ACROSS THE REGION THIS AFTERNOON AND TONIGHT.  THESE
STORMS ARE NOT EXPECTED TO BE SEVERE...HOWEVER...BRIEF GUSTY WINDS
AND BRIEF HEAVY DOWNPOURS ARE LIKLEY.

ON TUESDAY AFTERNOON AND TUESDAY NIGHT THERE EXISTS A SLIGHT RISK
FOR SOME SEVERE THUNDERSTORMS ACROSS THE REGION AS A COLD FRONT
APPROACHES FROM THE NORTHWEST.

MERZLOCK