[BNAWX] Severe Storm Outlook Narrative

[Nashville EMWIN]

ACUS11 KWNS 080741
SWOMCD
SPC MCD 080738
NCZ000-SCZ000-GAZ000-TNZ000-081045-

MESOSCALE DISCUSSION 2187
NWS STORM PREDICTION CENTER NORMAN OK
0238 AM CDT WED SEP 08 2004

AREAS AFFECTED...PORTIONS SRN/CENTRAL NC...MUCH OF SC

CONCERNING...TORNADO WATCH 812...

VALID 080738Z - 081045Z

TORNADO THREAT CONTINUES ACROSS WW AREA AMIDST GENERALLY FAVORABLE
SHEAR ENVIRONMENT.  INSTABILITY RANGES FROM VERY MARGINAL OVER MUCH
OF PIEDMONT -- I.E. LESS THAN 200 J/KG SBCAPE IN 6Z GSO RAOB -- TO
AROUND 1500 J/KG OVER COASTAL SC AND SERN NC...USING MODIFIED
RUC/ETA SOUNDINGS.  SFC MESOANALYSIS SHOWS CYCLONE CENTER OVER
EXTREME N-CENTRAL GA DRIFTING NNE...AND WEAK TROUGH EWD ACROSS
CENTRAL SC TO VICINITY ILM.  EARLIER DIFFERENTIAL HEATING BOUNDARY
ASSOCIATED WITH RAIN-COOLED AIR MASS HAS BECOME QUITE DIFFUSE
AGAIN...NOW THAT DIFFERENTIAL/DIABATIC HEATING HAS BEEN LOST FOR 6-8
HOURS. ALTHOUGH SUCH A BOUNDARY MAY AGAIN DEVELOP BY MIDMORNING
AFTER A FEW HOURS OF INSOLATION...EXPECT SUPERCELL FOCUS AND TORNADO
POTENTIAL IN MEANTIME TO BE MORE ISOLATED AND SPORADIC ACROSS WW
AREA.  PROBABILITIES APPEAR HIGHEST OVER NRN HALF OF WW -- FROM
CENTRAL SC NWD -- WHERE 0-1 KM SRH UP TO 450 J/KG PREVAILS PER
OBSERVED GSO HODOGRAPH.

FARTHER S...LOW LEVEL HODOGRAPH CURVATURE DECREASES...WITH MOST
STORMS MOVING NEAR TO OR ALONG HODOGRAPH HAVING LINEAR
CHARACTERISTICS -- I.E. LINE OVER AIKEN BARNWELL/ALLENDALE COUNTIES
SC AT 730Z.  IN THIS ENVIRONMENT SRH IS LARGE ONLY FOR DISCRETE
CELLS MOVING WITH SIGNIFICANT EWD COMPONENT -- RIGHTWARD OF BOTH
BOUNDARY LAYER WIND AND OF SHEAR VECTOR THROUGH CAPE BEARING LAYER.
STILL...TORNADO POTENTIAL HAS NOT DIMINISHED ENOUGH YET TO JUSTIFY
REMOVING SRN SC FROM WW.

..EDWARDS.. 09/08/2004

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

ATTN...WFO...MHX...RAH...ILM...RNK...CHS...CAE...GSP...MRX...FFC...

31807794 32378221 36148222 35567798



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