Severe Storm Outlook Narrative (AC)
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000
ACUS11 KWNS 282044
SWOMCD
SPC MCD 282043
ILZ000-282245-

MESOSCALE DISCUSSION 1631
NWS STORM PREDICTION CENTER NORMAN OK
0343 PM CDT THU AUG 28 2014

AREAS AFFECTED...PORTIONS OF CNTRL IL

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 282043Z - 282245Z

PROBABILITY OF WATCH ISSUANCE...20 PERCENT

SUMMARY...THUNDERSTORMS CROSSING THE MS RIVER MAY CONTINUE TO SPREAD
EWD/ESEWD INTO/ACROSS CNTRL IL DURING THE AFTERNOON AND COULD
PRODUCE ISOLATED INSTANCES OF MARGINALLY SVR HAIL/WIND. HOWEVER...WW
ISSUANCE IS UNLIKELY.

DISCUSSION...THUNDERSTORMS THAT EVOLVED WITHIN A ZONE OF WEAK WARM
ADVECTION ACROSS SRN IA AND NRN MO HAVE LOOSELY ORGANIZED INTO A
MULTICELL CLUSTER CURRENTLY APPROACHING/CROSSING THE MS RIVER. SFC
OBSERVATIONS DO NOT REVEAL ANY SUBSTANTIAL PRESSURE RISES IN THE
WAKE OF THIS ACTIVITY...SUGGESTING LIMITED SPATIAL EXTENT/DEPTH OF
ANY MESOSCALE COLD POOL. REGARDLESS...THIS ACTIVITY LIES ALONG AN
INSTABILITY GRADIENT INVOF A FRONT ANALYZED FROM BURLINGTON IOWA TO
MATTOON ILLINOIS. THE AIR MASS S OF THIS BOUNDARY HAS BECOME
STRONGLY UNSTABLE OWING TO INSOLATION AMIDST LOWER 70S SFC
DEWPOINTS...WITH MODIFICATIONS TO THE 12Z ILX RAOB SUGGESTING MLCAPE
AROUND 2000-2500 J/KG. WITH 20-25-KT MID-LEVEL WSWLYS SAMPLED BY THE
DVN VWP...STORMS WILL LIKELY CONTINUE TO EXPERIENCE FORWARD
PROPAGATION INTO PORTIONS OF CNTRL IL INVOF THE BOUNDARY.
HOWEVER...THERE MAY BE SOME TENDENCY FOR NEW CELL DEVELOPMENT TO
FAVOR SRN FLANKS OF ANTECEDENT CONVECTION OWING TO MORE UNSTABLE
INFLOW OVER THESE AREAS. ISOLATED INSTANCES OF SVR WIND/HAIL MAY
ACCOMPANY THIS ACTIVITY...THOUGH THE LACK OF STRONGER DEEP-LAYER
SHEAR WILL LIKELY BE A DETERRENT TO A MORE
SUBSTANTIAL/GREATER-COVERAGE SVR-TSTM POTENTIAL.

..COHEN/MEAD.. 08/28/2014

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

ATTN...WFO...LOT...ILX...LSX...DVN...

LAT...LON   40959059 40758876 40148825 39488861 39389024 40139129
            40959059



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