Severe Storm Outlook Narrative (AC)
Issued by NWS

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000
ACUS11 KWNS 271258
SWOMCD
SPC MCD 271257
INZ000-KYZ000-ILZ000-MOZ000-271500-

MESOSCALE DISCUSSION 0800
NWS STORM PREDICTION CENTER NORMAN OK
0757 AM CDT WED MAY 27 2015

AREAS AFFECTED...PARTS OF SRN/SERN IL...FAR SERN MO...WRN KY...AND
SWRN IND

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 271257Z - 271500Z

PROBABILITY OF WATCH ISSUANCE...40 PERCENT

SUMMARY...A SEVERE WEATHER WATCH MAY BE NEEDED LATER THIS MORNING
INTO THE AFTERNOON ACROSS PARTS OF THE LOWER OH VALLEY AS ONGOING
STORMS IN SERN MO AND ADJACENT SWRN IL ADVANCE EAST AND INCREASE IN
COVERAGE AND INTENSITY...WITH HAIL AND DAMAGING WINDS THE PRIMARY
THREATS.

DISCUSSION...AT 1240Z...MOSAIC RADAR IMAGERY INDICATED AN ORGANIZED
CLUSTER OF STORMS ADVANCING TO THE EAST-NORTHEAST AT 35-40 KT ACROSS
SERN MO AND ADJACENT SWRN IL.  THE CURRENT ENVIRONMENT IMMEDIATELY
DOWNSTREAM OF THESE STORMS INTO THE LOWER OH VALLEY IS MARGINALLY
UNSTABLE.  HOWEVER...EXPECTED MOISTENING OF THE BOUNDARY LAYER PER
SLY LOW-LEVEL WINDS AND THE ONSET OF DIABATIC HEATING PER BREAKS IN
THE CLOUDS ACROSS THE LOWER OH VALLEY PER VISIBLE SATELLITE IMAGERY
SUGGESTS THE AIR MASS SHOULD BECOME MODERATELY UNSTABLE.

CURRENT TRENDS IN IR IMAGERY INDICATED CLOUD TOP WARMING WITH THE
SERN MO/SWRN IL CLUSTER OF STORMS WHICH MAY SUGGEST A MINIMUM IN THE
SEVERE WEATHER THREAT DURING THE NEXT HOUR.  HOWEVER...FORCING FOR
ASCENT ATTENDANT TO THE MCV WITH THE MO/IL CLUSTER AND WITHIN THE
SRN EXTENT OF THE UPPER GREAT LAKES SHORTWAVE TROUGH PROVIDES
CONCERN FOR RE-STRENGTHENING OF STORMS AS THIS SYSTEM MOVES INTO A
MODESTLY SHEARED /EFFECTIVE BULK SHEAR OF 30-35 KT/ AND A
DESTABILIZING ENVIRONMENT.

..PETERS/HART.. 05/27/2015

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

ATTN...WFO...LMK...IND...PAH...ILX...LSX...

LAT...LON   39468591 38368610 37448705 36778823 36668926 36818965
            37908903 39228833 39878792 40278729 40388623 39848604
            39468591



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