027
ACUS11 KWNS 151531
SWOMCD
SPC MCD 151530
MDZ000-PAZ000-WVZ000-VAZ000-152030-
MESOSCALE DISCUSSION 2268
NWS STORM PREDICTION CENTER NORMAN OK
0930 AM CST SUN DEC 15 2024
AREAS AFFECTED...PORTIONS OF WEST VIRGINIA INTO WESTERN MARYLAND AND
SOUTHWESTERN PENNSYLVANIA
CONCERNING...WINTER MIXED PRECIPITATION
VALID 151530Z - 152030Z
SUMMARY...FREEZING RAIN SHOULD GRADUALLY INCREASE INTO THE LATE
MORNING AND EARLY AFTERNOON HOURS, WITH SOME SLEET OR SNOW ALSO
POSSIBLE. UP TO .06/3 HR ICE ACCRETION RATES CANNOT BE RULED OUT,
ESPECIALLY IN HIGHER-TERRAIN AREAS.
DISCUSSION...A PRONOUNCED MID-LEVEL TROUGH IS PROGRESSING EASTWARD
ACROSS THE OH VALLEY, ENCOURAGING LOW-LEVEL WARM AIR/MOISTURE
ADVECTION OVER PORTIONS OF THE APPALACHIANS. HERE, QG ASCENT IS
SUPPORTING A BROAD SHIELD OF PRECIPITATION, WHICH IS BEGINNING TO
APPROACH A WEDGE OF SUB-FREEZING LOW-LEVEL TEMPERATURES OVER
HIGHER-TERRAIN AREAS. SURFACE OBSERVATIONS FROM HARDY COUNTY, WV TO
CAMBRIA COUNTY, PA SHOW TEMPERATURES AROUND OR BELOW FREEZING, WITH
WET BULB TEMPERATURES WELL BELOW FREEZING OVER SEVERAL LOCALES. 15Z
MESOANALYSIS CONTINUES TO SHOW 925-850 MB CAA OVER THE HIGHER
TERRAIN, WHICH WILL FURTHER SUPPORT FREEZING RAIN POTENTIAL, PERHAPS
WITH SOME SLEET OR SNOW MIXED IN. THE BEST CHANCE FOR .06/3HR ICE
ACCRETION RATES, AS WELL AS SOME SLEET OR SNOW, WILL BE LATE THIS
MORNING INTO THE AFTERNOON HOURS, AS ALSO SHOWN BY THE LATEST HRRR
AND HREF PROBABILISTIC GUIDANCE.
..SQUITIERI.. 12/15/2024
..PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT
ATTN...WFO...CTP...LWX...PBZ...RLX...
LAT...LON 38687964 39297928 39857927 40527896 40647851 40497812
40037806 39357826 38937852 38677891 38547926 38687964
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