504 
ACUS11 KWNS 281757
SWOMCD
SPC MCD 281756 
INZ000-ILZ000-WIZ000-282000-

MESOSCALE DISCUSSION 1132
NWS STORM PREDICTION CENTER NORMAN OK
1256 PM CDT WED MAY 28 2003

AREAS AFFECTED...SRN WI...NRN/CNTRL IL...WRN IND

CONCERNING...SEVERE THUNDERSTORM POTENTIAL 

VALID 281756Z - 282000Z

CONVECTIVE TRENDS ARE BEING MONITORED FOR THE POSSIBILITY OF A WW.

60 TO 70 KT 500 MB JET STREAK CONTINUES TO DIG SOUTHEASTWARD ACROSS
THE UPPER MISSISSIPPI VALLEY...CONTRIBUTING TO LARGE-SCALE ASCENT 
AND DESTABILIZATION SUFFICIENT FOR ONGOING CONVECTIVE DEVELOPMENT
ACROSS SOUTHERN WISCONSIN AND NORTHERN ILLINOIS.  ACTIVITY IS MOSTLY
DEVELOPING ALONG/WEST OF MID-LEVEL SHEAR AXIS...WHERE BREAKS IN
CLOUD COVER HAVE ALLOWED HEATING OF LOWER-LEVEL AIR MASS MOISTENED
BY WARM ADVECTION CONVECTIVE BAND NOW SPREADING ACROSS EAST CENTRAL
ILLINOIS/NORTHWEST INDIANA.

MODELS ARE SIMILAR IN SUGGESTING STRONGEST FORCING WILL SHIFT
WEST/SOUTHWEST OF CHICAGO INTO THE CHAMPAIGN/DECATUR/MATTOON AREAS
BY PEAK AFTERNOON HEATING /AROUND THE 21-22Z TIME FRAME/.  THIS
APPEARS LIKELY TO PROVIDE FOCUS FOR MOST INTENSE CONVECTIVE
DEVELOPMENT IN ENVIRONMENT WITH MEAN MIXED LAYER CAPE INCREASING UP
TO AROUND 1000 J/KG.  STRONG NORTHWESTERLY MID-LEVEL FLOW WILL
PROVIDE FAVORABLY SHEARED ENVIRONMENT FOR UPDRAFT ROTATION...AND
ISOLATED SUPERCELLS APPEAR POSSIBLE.  THIS WILL ENHANCE POTENTIAL
FOR LARGE HAIL/GUSTY WINDS IN STRONGEST CELLS.

..KERR.. 05/28/2003

PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...IND...LOT...ILX...MKX...DVN...

42658904 42288842 41378794 40618745 39748786 39578912
39988969 41108953 42138967