[BNAWX] Severe Storm Outlook Narrative

[EMWIN Server]

ACUS11 KWNS 211948
SWOMCD
SPC MCD 211947
ALZ000-TNZ000-MSZ000-ARZ000-212215-

MESOSCALE DISCUSSION 1529
NWS STORM PREDICTION CENTER NORMAN OK
0247 PM CDT SAT JUL 21 2012

AREAS AFFECTED...SRN AR...NRN MS...NRN AL...PARTS OF FAR SRN TN

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 211947Z - 212215Z

PROBABILITY OF WATCH ISSUANCE...5 PERCENT

SUMMARY...A VERY ISOLATED THREAT FOR SVR THUNDERSTORMS WILL EXIST
ACROSS PARTS OF THE MID-SOUTH THROUGH THE AFTERNOON...AND WW
ISSUANCE IS NOT NEEDED.

DISCUSSION...LATEST SFC MESOANALYSIS INDICATES A QUASI-STATIONARY
FRONT EXTENDING FROM NORTH OF DE QUEEN AR TOWARD SRN SECTIONS OF THE
MEMPHIS AREA AND FARTHER EAST INTO FAR SRN PARTS OF MIDDLE TN.
VISIBLE SATELLITE LOOP INDICATES INCREASINGLY AGITATED CUMULUS ALONG
THE BOUNDARY. THIS IS ESPECIALLY THE CASE WITHIN 50-75 MILES EITHER
SIDE OF THE MISSISSIPPI RIVER...WHERE WATER VAPOR IMAGERY REVEALS A
ZONE OF MODESTLY ENHANCED MID-LEVEL MOISTURE...PERHAPS IN
ASSOCIATION WITH A LOBE OF ASCENT ACCOMPANYING A SWD-MOVING IMPULSE
OVER THE ERN FLANK OF A CNTRL CONUS RIDGE. OTHERWISE...THE REGION IS
DISPLACED TO THE N/NW OF A PLUME OF RICHER DEEP MOISTURE...WITH
COMPARATIVELY MORE DRY AIR IN PLACE ACROSS THE AREA -- PW BETWEEN
1.5 AND 1.6 INCHES PER GPS DATA. HOWEVER...STEEP LOW-LEVEL LAPSE
RATES AMIDST SFC DEWPOINTS IN THE LOWER/MIDDLE 70S ARE SUPPORTING
GENERALLY 1500-2500 J/KG OF MLCAPE NEAR AND SOUTH OF THE
FRONT...WHICH WILL YIELD A THREAT FOR VIGOROUS CONVECTIVE UPDRAFTS
WITH SWWD/SWD-MOVING STORMS INTO EARLY EVENING.

ALONG WITH A VERY ISOLATED THREAT FOR MARGINALLY SVR HAIL...A DMGG
WIND GUST OR TWO CANNOT BE RULED OUT GIVEN DCAPE VALUES IN EXCESS OF
1100 J/KG. HOWEVER...EFFECTIVE BULK SHEAR MAGNITUDES AOB 20 KT
FOSTERING A PREDOMINANTLY PULSE CONVECTIVE MODE...AND THE
ANTICIPATED LIMITED STORM COVERAGE OWING TO RELATIVELY DRIER AIR
ALOFT IN PLACE...SHOULD KEEP ANY SVR THREAT VERY ISOLATED.

..COHEN/HART.. 07/21/2012

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

ATTN...WFO...OHX...BMX...HUN...MEG...JAN...LZK...SHV...

LAT...LON   35169009 35308892 35338739 35218609 34898587 34578646
            34278807 34048975 33809039 33209178 33099288 33289373
            33639409 34089424 34439366 34639249 34939132 35169009



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