AREAS AFFECTED...FAR NERN IA...SRN WI...FAR NRN IL
CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY
VALID 091527Z - 091800Z
PROBABILITY OF WATCH ISSUANCE...5 PERCENT
SUMMARY...AN ORGANIZED CLUSTER OF THUNDERSTORMS IS EXPECTED TO
PERSIST TODAY ACROSS SRN WI AND INTO WRN LOWER MI...BUT SEVERE
WEATHER IS NOT ANTICIPATED. MARGINAL HAIL MAY FALL.
DISCUSSION...A CLUSTER OF THUNDERSTORMS IS CURRENTLY BEING FORCED BY
STRONG WARM ADVECTION N OF THE SYNOPTIC FRONT WHICH LIES ACROSS
CNTRL IA AND NRN IL. HIGH RESOLUTION MODELS HAVE A GOOD HANDLE ON
THIS AREA OF STORMS...AND SUGGEST THE SYSTEM MAY PERSIST AS FAR E AS
LOWER MI BY LATE AFTERNOON. WITH A CONSTANT INFLUX OF ELEVATED
INSTABILITY...AS WELL AS LONG HODOGRAPHS FAVORING FORWARD
PROPAGATION...THIS SOLUTION SEEMS PLAUSIBLE.
ENVIRONMENTALLY...INSTABILITY SHOULD REMAIN WEAK...AND THE COOL
BOUNDARY LAYER SHOULD MINIMIZE MELTING OF SMALL HAIL WITH MARBLE TO
NICKEL TYPE MAX HAIL SIZES POSSIBLE. SEVERE WINDS ARE UNLIKELY GIVEN
THE VERY COOL AND STABLE BOUNDARY LAYER.
LATER IN THE DAY INTO NRN IL...ISOLATED STORMS COULD FORM NEAR THE
WARM FRONT WHERE HEATING WILL RESULT IN SOME DESTABILIZATION.
HOWEVER...THEY SHOULD BE RATHER WEAK AND DISORGANIZED WITH RIDGING
ALOFT AND WEAK FORCING.
..JEWELL/THOMPSON.. 04/09/2013
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...APX...GRR...GRB...LOT...MKX...DVN...ARX...
LAT...LON 42578738 42379068 42529132 42919153 43429121 44108754
44368611 44168581 43698558 43198551 42808574 42658579
42578738
