Severe Storm Outlook Narrative (AC)
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000
ACUS11 KWNS 210135
SWOMCD
SPC MCD 210134
INZ000-ILZ000-210400-

MESOSCALE DISCUSSION 1751
NWS STORM PREDICTION CENTER NORMAN OK
0834 PM CDT SAT SEP 20 2014

AREAS AFFECTED...PORTIONS OF INDIANA AND ERN IL

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 210134Z - 210400Z

PROBABILITY OF WATCH ISSUANCE...20 PERCENT

SUMMARY...THE RISK FOR THUNDERSTORMS TO PRODUCE ISOLATED INSTANCES
OF MARGINALLY SVR HAIL WILL EXIST INTO THE LATE EVENING HOURS.
HOWEVER...THE ISSUANCE OF A WW IS UNLIKELY.

DISCUSSION...CHICAGO/ROMEOVILLE AND INDIANAPOLIS VWPS INDICATE A
VERTICALLY VEERING WIND PROFILE IN THE LOWEST 1 KM AGL...ASSOCIATED
WITH A MODEST WAA PATTERN IN THE WAKE OF AN EARLIER ROUND OF
CONVECTION THAT AFFECTED AREAS NEAR AND N OF THE INTERSTATE 70
CORRIDOR. AS A RESULT...MOSAIC RADAR IMAGERY INDICATES A RECENT
UPTICK IN WIDELY SCATTERED CONVECTIVE CORES...LIKELY ROOTED ATOP THE
COOL DOME DEPOSITED BY EARLIER CONVECTION. LARGE-SCALE ASCENT MAY
INCREASE DURING THE NEXT SEVERAL HOURS AS A MID-LEVEL VORT MAX
APPROACHES FROM THE UPPER MS VALLEY...AND SUPPORTS A FURTHER
INCREASE IN ELEVATED CONVECTIVE COVERAGE. THE 00Z ILX RAOB INDICATES
AMPLE BUOYANCY FOR INFLOW BASED TO THE W/SW /MLCAPE AROUND 2000 J/KG
AT ILX/...WHICH MAY SUPPORT A FEW VIGOROUS UPDRAFTS INTO THE LATE
EVENING HOURS. AND...WITH AROUND 40 KT OF 0-6-KM BULK SHEAR SAMPLED
BY THE IND VWP...A FEW SUSTAINED CONVECTIVE ELEMENTS WITH MARGINALLY
SVR HAIL MAY OCCUR. HOWEVER...GROWING NOCTURNAL MLCINH WILL LIKELY
PREVENT A MORE SUBSTANTIAL SVR-TSTM RISK FROM OCCURRING.

..COHEN/CORFIDI.. 09/21/2014

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

ATTN...WFO...ILN...IWX...IND...LOT...ILX...

LAT...LON   41168758 41498656 41428535 41188505 40618488 39698508
            39118655 39118830 40018823 41168758




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