MESOSCALE DISCUSSION 2610 NWS STORM PREDICTION CENTER NORMAN OK 0539 AM CST SUN DEC 14 2003 AREAS AFFECTED...SCENTRAL PA / WRN MD PANHANDLE / ERN WV PANHANDLE... CONCERNING...HEAVY SNOW VALID 141139Z - 141745Z HEAVY SNOW IS FORECAST ALONG AND WEST OF THE APPALACHIAN FRONT FROM S CENTRAL PA SWD INTO ERN WV OVER THE NEXT 3 TO 6 HOURS. SNOWFALL RATES OF 1 TO LOCALLY 2 INCHES PER HOUR WILL BE POSSIBLE. RADAR MOSAIC LOOP AND SURFACE OBSERVATIONS CONFIRM THAT CYCLOGENESIS IS UNDERWAY ACROSS ERN NC ATTM...MUCH IN LINE WITH SCENARIO DEPICTED BY 06Z ETA RUN. THE MODEL SUGGESTS THAT THIS LOW WILL DEEPEN AND MOVE NWD TO THE CHESAPEAKE BAY REGION BY 14/18Z...WITH INTENSIFYING ESELY LOW-LEVEL JET TO THE NORTH OF THIS LOW. VERY STRONG LOW-LEVEL THETA-E ADVECTION ASSOCIATED WITH THE LOW-LEVEL JET WILL SUPPORT CONTINUED WIDESPREAD / MODERATE TO HEAVY PRECIPITATION. AS LOW-LEVEL TEMPERATURES WARM FROM S-N ACROSS THIS REGION...EXPECT SNOW TO CHANGE OVER TO A WINTRY MIX EAST OF THE APPALACHIANS WITH TIME. HOWEVER...ELY COMPONENT OF LOW-LEVEL FLOW UPSLOPING OVER THE APPALACHIANS WILL LIKELY RESULT IN SUFFICIENT COOLING TO OFFSET THE WARM ADVECTION...ALLOWING THE LOWER TROPOSPHERE TO REMAIN BELOW FREEZING FROM THE APPALACHIAN FRONT WWD. THEREFORE...IT APPEARS ATTM THAT PRECIPITATION WILL LIKELY REMAIN PREDOMINANTLY IN THE FORM OF SNOW ACROSS THIS REGION...WITH 1 TO LOCALLY 2 INCH PER HOUR SNOWFALL RATES EXPECTED OVER THE NEXT 4 TO 6 HOURS. ..GOSS.. 12/14/2003 ATTN...WFO...CTP...LWX...PBZ... 41397737 41327673 40847628 39847774 39077829 39027894 39417969 40587893
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