AREAS AFFECTED...SRN LWR MI...NRN IL...NRN IND...AND NRN OH
CONCERNING...SEVERE POTENTIAL...WATCH LIKELY
VALID 071252Z - 071445Z
PROBABILITY OF WATCH ISSUANCE...80 PERCENT
SUMMARY...TSTMS EXPECTED TO INCREASE IN COVERAGE AND STRENGTH
THROUGH LATER THIS MORNING OVER SRN LWR MI AND NEARBY PORTIONS OF
NRN IL...NRN IND...AND NRN OH AS SFC HEATING ERODES NOCTURNAL SFC
STABLE LAYER. A WW MAY BE REQUIRED SHORTLY DUE TO ASSOCIATED THREAT
FOR DMGG WIND AND SVR HAIL.
DISCUSSION...GUST FRONT MARKING THE SRN EDGE OF ELONGATING COLD POOL
LEFT BY OVERNIGHT SQLN IN WI AND CNTRL MI HAS BECOME ORIENTED
ROUGHLY W-E OVER SRN LWR MI...PARALLEL TO SEASONABLY STRONG /30-50
KT/ 700-500 MB FLOW ACROSS REGION. THIS BOUNDARY WILL CONTINUE TO
SERVE AS A SOURCE OF LOW-LVL UPLIFT AS IT DRIFTS SLOWLY S ACROSS THE
REMAINDER OF LWR MI INTO NRN PARTS OF IL...IND...AND OH LATER THIS
MORNING.
WITH PARTLY TO MOSTLY CLEAR SKIES PRESENT S OF GUST FRONT...SFC
HEATING SHOULD RESULT IN FAIRLY RAPID EROSION OF SFC-BASED NOCTURNAL
STABLE LAYER OVER REGION. UPSTREAM 12Z RAOBS AT DVN AND ILX SHOW
PRESENCE OF DEEP EML THAT...GIVEN SEASONABLY STRONG WLY FLOW ON SRN
FRINGE OF UPR MI VORT MAX...WILL SPREAD RAPIDLY DOWNSTREAM ACROSS
SRN LWR MI AND ADJACENT IND/OH THROUGH MIDDAY. COUPLED WITH FAIRLY
RICH LOW-LVL MOISTURE /PW AOA 1.50 INCHES/ AND 30-35 KT WLY DEEP
SHEAR...SETUP MAY SUPPORT DEVELOPMENT OF CLUSTERS OF SUSTAINED
STORMS INCLUDING EMBEDDED ROTATING STRUCTURES/LEWPS CAPABLE OF DMGG
WIND AND SVR HAIL.
STORM TRENDS WILL CONTINUE TO BE MONITORED...BUT IT APPEARS THAT A
WW MAY BE NEEDED IN THE NEXT HOUR OR SO.
..CORFIDI/BROYLES.. 08/07/2013
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...CLE...ILN...DTX...IWX...GRR...IND...LOT...
LAT...LON 42308818 42378645 42278477 42458357 42578234 41708138
41058184 40668380 40688606 40928822 41618882 42308818
