AREAS AFFECTED...NERN MO...CNTRL IL...W-CNTRL IND
CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE
VALID 202027Z - 202130Z
PROBABILITY OF WATCH ISSUANCE...60 PERCENT
SUMMARY...PROSPECTS FOR TSTM DEVELOPMENT ARE SOMEWHAT UNCERTAIN
ACROSS W-CNTRL IND WWD INTO NERN MO...BUT THE ENVIRONMENT IS
FAVORABLE FOR DMGG WINDS AND HAIL GIVEN STRONG
HEATING/DESTABILIZATION. CONVECTIVE TRENDS ARE BEING MONITORED FOR
A POSSIBLE WW...PARTICULARLY ACTIVITY DEVELOPING NEWD FROM SWRN MO
TOWARDS THE MID-MS VALLEY.
DISCUSSION...RADAR/SATELLITE TRENDS SHOW A DECAYING TSTM CLUSTER/MCV
MOVING ACROSS N-CNTRL IL...WITH AN INCREASE IN SHALLOW BOUNDARY
LAYER CU NOTED ACROSS E-CNTRL IL. THIS APPEARS TO BE DEVELOPING
WITHIN A WEAK CONFLUENCE AXIS WHICH EXTENDS FROM 30 SE MMO TO 20 SSW
SPI. BOTH MODIFIED 12Z RAOBS AND 12Z NAM FORECAST SOUNDINGS SUGGEST
MLCAPE VALUES HAVE INCREASED TO 1000-1500 J/KG. WHILE THERE IS STILL
SOME UNCERTAINTY TO WHAT DEGREE TSTMS WILL INTENSIFY/ORGANIZE OVER
IL...A THREAT FOR DMGG WINDS AND LARGE HAIL COULD DEVELOP GIVEN
STEEP LOW-LEVEL LAPSE RATES AND MODERATELY STRONG DEEP-LAYER SHEAR.
ADDITIONALLY...TSTMS CURRENTLY DEVELOPING OVER WRN MO SHOULD
EXPAND/DEVELOP NEWD TOWARDS E-CNTRL MO THROUGH LATE AFTERNOON. IT IS
UNCERTAIN WHETHER A WW WILL BE REQUIRED WITHIN THE NEXT 1-2
HRS...BUT CONVECTIVE TRENDS CONTINUE TO BE MONITORED.
..ROGERS/KERR.. 05/20/2013
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...IWX...IND...LOT...ILX...LSX...
LAT...LON 39918754 39488867 39078960 38749051 38819154 39059224
39719220 40199029 40468932 40988874 41188822 41298728
41208691 40788656 40298664 39918754
