672
ACUS11 KWNS 082043
SWOMCD
SPC MCD 082042
PAZ000-MDZ000-NYZ000-WVZ000-OHZ000-090045-
MESOSCALE DISCUSSION 0076
NWS STORM PREDICTION CENTER NORMAN OK
0242 PM CST SAT FEB 08 2025
AREAS AFFECTED...NORTHWEST TO SOUTH-CENTRAL PENNSYLVANIA INTO FAR
NORTHERN WEST-VIRGINIA/MARYLAND
CONCERNING...WINTER MIXED PRECIPITATION
VALID 082042Z - 090045Z
SUMMARY...SNOW TRANSITIONING TO A COMBINATION OF SLEET AND FREEZING
RAIN IS EXPECTED TO OVERSPREAD NORTHWEST TO SOUTH-CENTRAL
PENNSYLVANIA AND FAR NORTHEAST WEST VIRGINIA/NORTHWEST MARYLAND
THROUGH THE LATE AFTERNOON HOURS. FREEZING RAIN RATES UP TO 0.03
IN/HOUR ARE POSSIBLE.
DISCUSSION...REGIONAL RADAR IMAGERY DEPICTS A SWATH OF STRATIFORM
PRECIPITATION OVERSPREADING OH WITH AN ADDITIONAL PRECIPITATION BAND
ASSOCIATED WITH STRENGTHENING ISENTROPIC ASCENT DEVELOPING ACROSS WV
INTO NORTHWEST VA/WESTERN MD. OVER THE PAST HOUR, SURFACE
OBSERVATIONS AND MPING REPORTS FROM NORTH-CENTRAL OH HAVE REPORTED A
MIXTURE OF FREEZING RAIN (WITH ONE-HOUR ACCUMULATIONS UP TO 0.03
INCHES) AND SLEET AS SURFACE TEMPERATURES WET-BULB DOWN TO THE UPPER
20S/LOW 30S. SLIGHTLY COOLER CONDITIONS ARE NOTED DOWNSTREAM ACROSS
PA WHERE SURFACE TEMPERATURES ARE LARGELY BELOW FREEZING WITH
DEWPOINTS IN THE TEENS TO MID 20S. INITIALLY SUB-FREEZING
TEMPERATURES THROUGHOUT THE COLUMN OVER PA SHOULD PROMOTE MAINLY
SNOW AS THE INITIAL P-TYPE AS PRECIPITATION BEGINS OVERSPREADING THE
REGION.
WITH TIME, STRENGTHENING MID-LEVEL WARM ADVECTION WILL RESULT IN A
1-4 C WARM NOSE WITHIN THE 850-700 MB LAYER. CONCURRENTLY, WET-BULB
COOLING WITHIN THE LOWEST KILOMETER WILL MAINTAIN SUB-FREEZING
TEMPERATURES NEAR THE SURFACE. THESE THERMODYNAMIC TRENDS WILL
PROMOTE A TRANSITION FROM MAINLY SNOW TO A MIX OF FREEZING RAIN AND
SLEET, SIMILAR TO RECENT UPSTREAM OBSERVATIONS. THE PROPENSITY FOR
ONE PRECIPITATION TYPE OVER THE OTHER WILL LARGELY DEPEND ON THE
STRENGTH OF THE WARM NOSE ALOFT, WHICH VARIES ACROSS RECENT
DETERMINISTIC SOLUTIONS LEADING TO LIMITED CONFIDENCE IN COVERAGE OF
SLEET/FREEZING RAIN AND ACCUMULATION AMOUNTS. REGARDLESS, MODERATE
TO HEAVY PRECIPITATION RATES - ESPECIALLY UNDER ANY EMBEDDED
CONVECTIVE ELEMENTS - MAY RESULT IN PERIODS OF MODERATE SLEET AND/OR
FREEZING RAIN.
..MOORE.. 02/08/2025
..PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT
ATTN...WFO...PHI...BUF...CTP...LWX...PBZ...CLE...
LAT...LON 39897939 40447889 40747894 40927924 40927988 41118051
41578058 41908037 42017987 42047877 42037851 41987816
41937785 41567717 41187668 40747624 40427611 40087610
39897628 39777661 39547796 39487856 39467902 39547937
39697946 39897939
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