Severe Storm Outlook Narrative (AC)
Issued by NWS

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000 ACUS11 KWNS 261329 SWOMCD SPC MCD 261328 PAZ000-MDZ000-WVZ000-VAZ000-261730- MESOSCALE DISCUSSION 1955 NWS STORM PREDICTION CENTER NORMAN OK 0728 AM CST WED NOV 26 2014 AREAS AFFECTED...PARTS OF SWRN VA / ERN AND NERN WV / S-CNTRL PA CONCERNING...HEAVY SNOW VALID 261328Z - 261730Z SUMMARY...SNOWFALL RATES AROUND 1 INCH PER HOUR ARE EXPECTED THIS MORNING. THE HEAVIER SNOWFALL RATES WILL INITIAL BE CONFINED TO LOCALIZED AREAS BUT WILL BECOME MORE WIDESPREAD TOWARDS THE MID-LATE MORNING HOURS. DISCUSSION...13Z SURFACE MESOANALYSIS SHOWS THE 32 DEG F ISOTHERM INVOF THE VA/WV BORDER NEAR AND W OF THE SHENANDOAH VALLEY NEWD INTO WRN MD AND S-CNTRL PA. OBSERVATIONAL TRENDS HAVE SHOWN THE AREA AOB FREEZING BECOMING MORE WIDESPREAD WITH TIME AS HEAVIER PRECIP RATES AND WET-BULB COOLING CONTRIBUTE TO COOLING PROCESSES NEAR THE SURFACE. THE 12Z RNK RAOB SHOWED THE TEMP PROFILE NEAR OR BELOW 0 DEG C FROM THE SURFACE UP THROUGH THE TROPOSPHERE...SUPPORTIVE OF SNOW P-TYPE. FARTHER NE...THE 12Z IAD RAOB SHOWED A TEMP PROFILE ABOVE FREEZING IN THE SURFACE-1 KM LAYER. MODELS INDICATE H7-H5 UPWARD VERTICAL MOTION TO MAXIMIZE OVER THE SRN HALF OF THE DISCUSSION AREA THROUGH 16Z WITH A SHIFT NWD NEAR AND NORTH OF THE MASON-DIXON LINE AFTER 16Z. MODELS SHOW THE DENDRITIC GROWTH ZONE /-12 TO -17 DEG C/ TO OVERLAP WITH STRONG UPWARD VERTICAL MOTION AND THIS WILL LIKELY FAVOR HEAVIER PRECIP RATES. A FURTHER EXPANSION IN AREA OF NEAR-SURFACE TEMPS AOB 32 DEG WILL FAVOR SNOW BECOMING MORE WIDESPREAD AND 1 INCH PER HOUR RATES WILL BECOME MORE COMMON THROUGH THE MID TO LATE MORNING HOURS. ..SMITH.. 11/26/2014 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...CTP...LWX...RNK...PBZ...RLX... LAT...LON 40337868 40647810 40717761 40437742 40047762 39307833 38627904 37168024 37148068 37318084 39527941 40337868

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