Severe Storm Outlook Narrative (AC)
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000
ACUS11 KWNS 021901
SWOMCD
SPC MCD 021900
MIZ000-WIZ000-ILZ000-022100-

MESOSCALE DISCUSSION 1587
NWS STORM PREDICTION CENTER NORMAN OK
0200 PM CDT SUN AUG 02 2015

AREAS AFFECTED...PORTIONS OF SRN/CNTRL WI...WRN/SRN MI

CONCERNING...SEVERE POTENTIAL...WATCH LIKELY

VALID 021900Z - 022100Z

PROBABILITY OF WATCH ISSUANCE...95 PERCENT

SUMMARY...STRONG TO SEVERE THUNDERSTORMS ARE EXPECTED TO DEVELOP
OVER THE NEXT FEW HOURS...WITH A PRIMARY THREAT FOR LARGE HAIL AND
DAMAGING WINDS. THESE STORMS WILL LIKELY EVOLVE INTO A
S/SEWD-PROGRESSING SQUALL LINE...WITH THE SEVERE THREAT
TRANSITIONING TO MAINLY DAMAGING WINDS. ADDITIONALLY...A TORNADO OR
TWO WILL BE POSSIBLE.

DISCUSSION...RECENT SFC OBSERVATIONS EXHIBIT WINDS VEERING TO THE
N/NW ACROSS PORTIONS OF NRN WI THIS AFTERNOON...AS WELL AS PRESSURE
RISES UPWARDS OF 1 MB/HR. THIS LOW-LEVEL MASS RESPONSE IS LIKELY A
MANIFESTATION OF STRONGER FORCING FOR ASCENT IMPINGING UPON THE
REGION FROM THE NW. THUS...AS SFC CONVERGENCE IS ENHANCED AND
MID-LEVEL ASCENT IS MAXIMIZED...CONVECTION SHOULD RAPIDLY INCREASE
IN COVERAGE THIS AFTERNOON FROM SRN/CNTRL WI EWD INTO WRN/CNTRL MI.
INDEED...A DEVELOPING CU FIELD OVER WI PROBABLY REPRESENTS THE
INITIAL REGION FOR INITIATION...WITH CONVECTION INCREASING
DOWNSTREAM INTO MI...LARGELY FOCUSED BY OUTFLOW BOUNDARIES FROM
EARLIER CONVECTION.

18Z RAOBS FROM GRB/DVN ILLUSTRATE STEEP MID-LEVEL LAPSE RATES OVER
THE REGION. IN COMBINATION WITH STRONG HEATING AND AMPLE LOW-LEVEL
MOISTURE...THIS THERMODYNAMIC ENVIRONMENT IS SUPPORTIVE OF INTENSE
VERTICAL ACCELERATION IN THE HAIL-GROWTH ZONE...SUGGESTING LARGE
HAIL SHOULD BE A THREAT WITH INITIAL QUASI-DISCRETE CELLS. AS
UPSCALE GROWTH INTO A SQUALL LINE OCCURS HOWEVER...THE PRIMARY
THREAT SHOULD TRANSITION TO DAMAGING WINDS...AIDED BY LOW/MID-LEVEL
FLOW OF 40-50 KTS AND STRONG SFC HEATING. FURTHERMORE...OBSERVED
PROFILES/MESOANALYSIS DISPLAY SOME VEERING WITH HEIGHT AND EFFECTIVE
SRH ON THE ORDER OF 100-200 M2/S2...HIGHLIGHTING THE POTENTIAL FOR A
TORNADO OR TWO AS WELL. AS SUCH...WATCH ISSUANCE IS LIKELY WITHIN
THE NEXT HOUR OR SO.

..PICCA/HART.. 08/02/2015

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

ATTN...WFO...DTX...GRR...GRB...LOT...MKX...ARX...MPX...

LAT...LON   43928576 43298441 42578414 42198439 42298650 42468867
            42608966 42839068 43329098 44329125 44589118 44938981
            44648775 43928576



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