AREAS AFFECTED...IA..WI...IL
CONCERNING...SEVERE POTENTIAL...SEVERE THUNDERSTORM WATCH LIKELY
VALID 281700Z - 281800Z
PROBABILITY OF WATCH ISSUANCE...80 PERCENT
SUMMARY...STRONG TO SEVERE TSTMS ARE EXPECTED TO DEVELOP AHEAD OF A
COLD FRONT MOVING INTO AREAS OF EXTREME ERN IA...MUCH OF WI...AND
NRN IL THROUGH THE AFTERNOON. A WATCH IS POSSIBLE ACROSS SOME OR
MOST OF THESE AREAS WITHIN THE NEXT HOUR OR TWO.
DISCUSSION...STRONG ASCENT ACCOMPANYING THE SHORT WAVE TROUGH MOVING
INTO ERN MN AND IA WILL LIKELY AID CONVECTIVE DEVELOPMENT ALONG AND
AHEAD OF A COLD FRONT CURRENTLY SITUATED FROM WRN WI SWWD INTO NERN
IA. AIRMASS AHEAD OF THE FRONT CONTINUES TO DESTABILIZE WITH HEATING
OF THE DAY AND SURFACE-BASED CAPE IS CURRENTLY NEARING 1000 J/KG IN
SOME LOCATIONS. A WIDE ARRAY OF MODEL GUIDANCE INDICATES A
REMARKABLY CONSISTENT SIGNAL FOR THE DEVELOPMENT AND INCREASING
COVERAGE OF DEEP CONVECTION...ESPECIALLY ACROSS NRN AND ERN
WI...THROUGH THIS AFTERNOON. THIS MODEL SIGNAL IS LIKELY A RESULT OF
FAVORABLE LARGE SCALE FORCING FOR ASCENT MOVING INTO THE REGION AND
A LACK OF STRONGER INHIBITION THAN WHAT HAS BEEN IN PLACE IN RECENT
DAYS.
AMBIENT DEEP-LAYER SHEAR OF 40KT WITHIN THE SERN FLANK OF THE LARGE
UPPER LOW TO THE WEST WILL SUPPORT INCREASING STORM ORGANIZATION
WITH SUPERCELLS AND BOWING LINE SEGMENTS POTENTIALLY EVOLVING WITH
TIME. LARGE HAIL AND LOCALLY DAMAGING WINDS MAY ACCOMPANY THE
STRONGER STORMS LATER TODAY.
..CARBIN.. 05/28/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...GRB...LOT...MKX...DVN...DLH...ARX...
LAT...LON 44159089 44949062 45459001 45808920 45568804 44598754
43768771 42898837 42078983 42279097 43049146 44159089
