ZCZC SPCSWOMCD ALL ACUS11 KWNS 121842 SPC MCD 121842 VAZ000-WVZ000-130045- MESOSCALE DISCUSSION 0091 NWS STORM PREDICTION CENTER NORMAN OK 1242 PM CST WED FEB 12 2014 AREAS AFFECTED...VA...SE WV CONCERNING...HEAVY SNOW VALID 121842Z - 130045Z SUMMARY...MODERATE TO HEAVY SNOW IS EXPECTED TO DEVELOP THIS AFTERNOON FROM SERN WV EWD ACROSS MUCH OF VA. SNOWFALL RATES OF 1 INCH PER HOUR WILL BECOME COMMON WITH LOCALLY HIGHER RATES. DISCUSSION...LATEST WATER VAPOR IMAGERY SHOWS AN UPPER-LEVEL TROUGH IN THE MS VALLEY WITH A LEAD SHORTWAVE TROUGH EXTENDING FROM THE SRN APPALACHIAN MTNS SEWD ACROSS SC. WIDESPREAD PRECIPITATION IS LOCATED JUST AHEAD OF THIS FEATURE IN A BROAD ZONE OF WARM ADVECTION FROM ERN GA NEWD INTO THE CAROLINAS. MODEL FORECASTS SUGGEST LARGE-SCALE ASCENT ALONG THIS ZONE WILL MOVE NWD OVER THE NEXT FEW HOURS BECOME INCREASINGLY ENHANCED ACROSS NRN NC AND VA LATE THIS AFTERNOON. THIS WILL AID THE DEVELOPMENT OF MODERATE TO HEAVY SNOWFALL ACROSS VA AND SERN WV LATE THIS AFTERNOON. THE 18Z SOUNDING FROM GREENSBORO NC SHOULD BE REPRESENTATIVE OF THE AIRMASS IN VA...SHOWING THE PRIMARY ZONE FOR DENDRITIC GROWTH BETWEEN 700 AND 500 MB. AS MOISTENING CONTINUES TO OCCUR BELOW 850 MB...AN ISOTHERMAL LAYER SHOULD BE FAVORABLE FOR HEAVY SNOW WITH RATES OF 1 INCH PER HOUR COMMON. LOCALLY HIGHER RATES COULD OCCUR WITHIN THE MORE ORGANIZED BANDING. ..BROYLES.. 02/12/2014 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...AKQ...LWX...RNK...RLX... LAT...LON 36588077 36738135 37038142 37408123 37728090 38058022 38307929 38467861 38487797 38387749 38137721 37727700 37187685 36697696 36587770 36588077 NNNN