[MCD] SWOMCD

[MCD at goshenarc.org]

ACUS11 KWNS 041537
SWOMCD
SPC MCD 041537 
ILZ000-IAZ000-041730-

MESOSCALE DISCUSSION 1152
NWS STORM PREDICTION CENTER NORMAN OK
1037 AM CDT SAT JUN 04 2005

AREAS AFFECTED...NRN/CNTRL IL

CONCERNING...SEVERE THUNDERSTORM POTENTIAL 

VALID 041537Z - 041730Z

TRENDS ARE BEING MONITORED FOR INCREASING SEVERE THREAT AND
POSSIBILITY OF A WW.

CLUSTER OF CONVECTION CONTINUES TO SLOWLY SPREAD THROUGH WEST
CENTRAL ILLINOIS.  ACTIVITY APPEARS TO BE IN WAKE OF MID-LEVEL SHORT
WAVE TROUGH AXIS LIFTING NORTHWARD INTO THE UPPER MISSISSIPPI
VALLEY...WHERE MID-LEVEL WARM ADVECTION INCREASES RAPIDLY AHEAD OF
NEXT SHORT WAVE PROGRESSING OUT OF THE CENTRAL ROCKIES.  THIS
FORCING IS SPREADING NORTHEASTWARD...AND COULD APPROACH THE CHICAGO
METROPOLITAN AREA...AND AREAS SOUTHWARD TO AROUND CHAMPAIGN BY
19-20Z.

THERMODYNAMIC ENVIRONMENT ACROSS MUCH OF NORTHERN/CENTRAL ILLINOIS
IS ALREADY POTENTIALLY MODERATELY UNSTABLE...WITH MOST UNSTABLE CAPE
ON THE ORDER OF 1000 J/KG.  MOIST BOUNDARY LAYER WILL CONTINUE TO
WARM INTO THE 80S AHEAD OF LINE...AND WITH PROGRESSION INTO PEAK
AFTERNOON HEATING...STORMS WILL BECOME INCREASINGLY BASED IN
DEEPENING BOUNDARY LAYER.

SOME UNCERTAINTY EXISTS ABOUT DAMAGING WIND POTENTIAL...WITH
ACTIVITY CURRENTLY ORIENTED PARALLEL TO MODERATELY STRONG AND
SHEARED SOUTHERLY MEAN FLOW REGIME.  HOWEVER...ENOUGH EVAPORATIVE
COOLING APPEARS POSSIBLE TO SUPPORT PERSISTENT SURFACE COLD POOL...
AND MODELS DO SUGGEST MID-LEVEL FLOW WILL GRADUALLY VEER TO A MORE
WESTERLY COMPONENT ACROSS MUCH OF NORTHERN ILLINOIS THROUGH THE
AFTERNOON HOURS.  IF THIS OCCURS...POTENTIAL FOR DAMAGING SURFACE
GUSTS WILL INCREASE WITH CONVECTION.  REGARDLESS...POTENTIAL FOR
MARGINALLY SEVERE HAIL APPEARS LIKELY TO INCREASE ONCE AGAIN WITHIN
NEXT HOUR OR TWO AND CONTINUE THROUGH THE AFTERNOON.

..KERR.. 06/04/2005

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

ATTN...WFO...LOT...ILX...LSX...DVN...

41089056 42079054 42268915 41778829 41018785 39968781
39328907 39238972 39639052 40079043 

WWWW