MESO: Mesoscale Discussion 0135

ACUS11 KWNS 191748
SWOMCD
SPC MCD 191747
VAZ000-NCZ000-WVZ000-TNZ000-KYZ000-192145-

MESOSCALE DISCUSSION 0135
NWS STORM PREDICTION CENTER NORMAN OK
1147 AM CST SUN FEB 19 2012

AREAS AFFECTED...FAR ERN KY AND SRN WV...WRN/S CNTRL VA...NWRN AND N
CNTRL NC

CONCERNING...HEAVY SNOW

VALID 191747Z - 192145Z

HEAVY SNOW IS BEGINNING TO DEVELOP ACROSS PORTIONS OF THE CNTRL
APPALACHIANS...LIKELY CONTINUING THROUGH THE AFTERNOON WHILE ALSO
SPREADING EWD WITH TIME. INCH AN HOUR RATES WILL OCCUR...ESPECIALLY
LATER THIS AFTERNOON. ISOLATED INSTANCES OF THUNDERSNOW MAY BE
POSSIBLE LATE THIS AFTERNOON INTO THE EARLY EVENING.

17Z SURFACE ANALYSIS SHOWS MOST MODEL SOLUTIONS ARE GENERALLY ON
TRACK WITH THE PROGRESSION OF A SURFACE LOW / ANALYZED NEAR THE SERN
GA/SWRN SC BORDER /...EXPECTED TO GRADUALLY SHIFT OFFSHORE. GREATEST
SURFACE PRESSURE FALLS OVER ERN NC AND ADJACENT WATERS CONFIRM THIS
PROGRESSION...WHICH WILL ALLOW SURFACE WINDS TO THE NORTH TO BACK TO
A MORE NLY DIRECTION...DRAWING COLDER TEMPERATURES INTO THE MID
ATLANTIC REGION. SOME COOLING HAS ALREADY BEEN NOTED...WITH 5 DEGREE
SURFACE TEMPERATURE FALLS OVER THE PAST 3 HRS ACROSS INTERIOR
PORTIONS OF SRN VA...NC...AND NWRN SC. COOLING HAS ALSO BEEN
PARTICULARLY NOTED NEAR ROANOKE WHERE DYNAMIC PROCESSES MAY BE
CONTRIBUTING TO AN OVERALL DROP IN TEMPERATURES THROUGHOUT THE
COLUMN. IN THIS AREA...THE APPROACHING UPPER WAVE NOTED ON WV
IMAGERY ACROSS THE TN VALLEY AS WELL AS FAVORABLE UPPER LEVEL JET
DYNAMICS SHOULD SUPPORT A CONTINUATION OF VERTICAL MOTION...WITH
MOISTENING FROM THE SOUTHWEST FURTHER ENHANCING HEAVY SNOWFALL
POTENTIAL THIS AFTERNOON.

IN THE ADJACENT AREAS TO THE EAST...FURTHER COOLING AND MOISTENING
WILL BE NECESSARY FOR THE ONSET OF SNOW/HEAVY SNOW...WHICH SHOULD
OCCUR LATER TODAY AS GREATER MOISTURE NOTED IN SC ADVECTS NWD AND
COLD AIR DAMMING CONTINUES. ADDITIONAL FORCING FOR ASCENT WILL
ARRIVE THIS EVENING AS ANOTHER SHORT WAVE /CURRENTLY OVER ERN MO/
PROGRESSES SEWD. TO THE WEST...A TRANSITORY THREAT OF HEAVY SNOW MAY
BE POSSIBLE AS COLD AIR ADVECTION OCCURS ON THE HEELS OF GREATER
MOISTURE.

..HURLBUT.. 02/19/2012

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

ATTN...WFO...AKQ...LWX...RAH...RNK...RLX...MRX...JKL...

LAT...LON 37608031 37627898 37217814 36547818 36287934 36318054
36128165 36948243 37208271 37468206 37608031

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