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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