Severe Thunderstorm Warning 47, NWS Chicago, IL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO IL
250 PM CDT THU AUG 9 2001

MODEL COMPARISONS WITH SFC DATA INDICATE AVN HAS BETTER HANDLE ON
COLD FRONT PLACEMENT WHICH STRETCHES AT 18Z FROM JUST W OF GRB TO
JUST E OF ALO. DEVELOPMENT SO FAR IN IA AND SRN WI HAS BEEN SPARTAN
WITH A FEW SHOWERS FROM MLI ON S THRU BRL. THIS MOVING RATHER SLOWLY
EAST AND PROBABLY WONT REACH CWA TIL 5PM. LOWER DBZ ON 88D INDICATE
THE LINE ASSOCIATED WITH THESE NWRN IL SHWRS APPEARS TO CONTINUE
NEWD THRU RFD TO THE MKE AREA. SAME LIGHT DBZ HIGHLITE THE COLD
FRONT ACROSS WI AND IA.

GOES SOUNDER INDICATES THE MKE AREA HAS SOME DECENT INHIBITION BUT
NOT SO MUCH REST OF NRN IL. ON THE OTHER HAND CAPES ARE BLO 1000 IN
NWRN IL. RICK DIMAIO AT FOX NOTED THE WESTERLY 850 WINDS NOT
SUPPORTIVE OF SEVERE WX WHICH SEEMS TO BE THE CASE ON UPPER AIR PLOT
ACROSS NRN IL. THUS MAY NOT BE RISK OF SEVERE TONIGHT AND MAY EVEN
ISSUE FCST WITH CHC POPS RATHER THAN LIKELY OR CATEGORICAL.

POST FRONTAL COOLING IMMINENT THOUGH LOOKING AT TEMPS AND DWPTS WEST
OF COLD FRONT. THUS WILL KEEP HEAT WARNG GOING WITH THE 330PM
PACKAGE AND HAVE EVENING SHIFT CANCEL IT WITH FROPA. THAT SHOULD PUT
THIS EVENT TO REST WITH WELCOMED COOLER AND DRIER AIR FOR FRIDAY AND
THE WEEKEND. GUIDANCE HAS ALREADY BACKED OFF FROM MID 70S FOR HIGHS
FRIDAY AND SATURDAY ON AVN AT LEAST AND WILL LIKELY GO WITH NEAR 80
OR 75 TO 80 RANGE.

.CHI...EXCESSIVE HEAT WARNING THRU THIS EVENING CHI METRO.

BRUMER