MESO: Mesoscale Discussion 2027

ACUS11 KWNS 072025
SWOMCD
SPC MCD 072025
NCZ000-SCZ000-072200-

MESOSCALE DISCUSSION 2027
NWS STORM PREDICTION CENTER NORMAN OK
0325 PM CDT SUN OCT 07 2012

AREAS AFFECTED...PORTIONS OF CNTRL SC AND COASTAL PLAIN / FAR SRN
COASTAL NC

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 072025Z - 072200Z

PROBABILITY OF WATCH ISSUANCE...20 PERCENT

SUMMARY...PORTIONS OF CNTRL SC EWD TO THE IMMEDIATE CAROLINA COAST
ARE BEING MONITORED FOR MORE WIDESPREAD CONVECTIVE INITIATION OVER
THE NEXT SEVERAL HOURS. IF/WHEN GREATER COVERAGE OF ROBUST TSTM
DEVELOPMENT IS UNDERWAY...THE PROBABILITY OF A SMALL SEVERE TSTM
WATCH MAY INCREASE.

DISCUSSION...WATER VAPOR IMAGERY SHOWS A VIGOROUS SHORTWAVE TROUGH
MOVING ACROSS THE OH VALLEY AND IS FORECAST TO MOVE ENEWD INTO PA BY
EVENING. 20Z SURFACE MESOANALYSIS SHOWS A RESIDUAL COLD
POOL/EFFECTIVE FRONT HAS PROGRESSED EWD TO THE IMMEDIATE NC COAST
THIS AFTERNOON AND HAS STALLED INVOF THE SEA BREEZE BOUNDARY.
FARTHER S...A WEAK LOW NEAR OGB AND CAE IS LOCATED WITHIN A CU FIELD
THAT EXTENDS FROM THE SC UPSTATE ESEWD INTO THE SC PIEDMONT AND
COASTAL PLAIN. IT IS NEAR AND S OF THESE SURFACE FEATURES WHERE THE
AIRMASS HAS DESTABILIZED WITH WEAKENING CINH. THE GLANCING
INFLUENCE OF LARGE SCALE ASCENT ASSOCIATED WITH THE AFOREMENTIONED
SHORTWAVE TROUGH...AND WEAK LOW LEVEL CONVERGENCE...MAY ALLOW A FEW
MORE STORMS TO EVENTUALLY DEVELOP OVER THE NEXT SEVERAL HOURS.

CONVECTION-ALLOWING MODELS FROM 12Z DEVIATE SUBSTANTIALLY FROM THE
OBSERVED EVOLUTION OF THE EFFECTIVE FRONT ALONG THE NC COAST...WITH
SEVERAL RECENT HRRR RUNS LARGELY VOID OF STORM DEVELOPMENT ACROSS
SC. THIS LENDS CONSIDERABLE UNCERTAINTY IN STORM COVERAGE.
NONETHELESS...FAVORABLE COMBINATION OF POTENTIAL INSTABILITY AND
DEEP LAYER SHEAR WOULD SEEMINGLY SUPPORT AT LEAST A LOWER-END SEVERE
RISK /ISOLD DMGG WIND AND/OR MARGINALLY SEVERE HAIL REPORT/.

..SMITH/WEISS.. 10/07/2012

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

ATTN...WFO...MHX...ILM...CHS...CAE...

LAT...LON 34757722 32778009 33838170 33818014 34757722

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