447
FOUS11 KWBC 141840
QPFHSD
PROBABILISTIC HEAVY SNOW AND ICING DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
140 PM EST SUN DEC 14 2025
VALID 00Z MON DEC 15 2025 - 00Z THU DEC 18 2025
..GREAT LAKES
DAYS 1-2...
SHORTWAVE OVER WESTERN ONTARIO WILL DIVE SOUTHEASTWARD TONIGHT,
BRINGING A CHANCE OF LIGHT SNOW TO THE UPPER LAKES. THE SYSTEM WILL
BRING A RELATIVELY BRIEF PERIOD OF LAKE ENHANCED SNOW TO THE LOWER
LAKES MONDAY FOLLOWED BY SOME LAKE EFFECT SNOWS OFF ONTARIO INTO
THE TUG HILL BEFORE WANING ON TUESDAY AS HEIGHTS RISE. WPC
PROBABILITIES FOR AT LEAST 4 INCHES OF SNOW ARE HIGHEST OVER THE
EASTERN U.P., NORTHWESTERN PA INTO NY, AND MOST ESPECIALLY INTO THE
TUG HILL AS ANY BANDING WILL BE RATHER VARIABLE.
..CASCADES AND NORTHERN ROCKIES
DAYS 2-3...
A LEAD WARM ATMOSPHERIC RIVER (AR) WILL BRING MOSTLY RAIN TO THE
PACNW MONDAY WITH HIGH SNOW LEVELS. COOLER POST-FRONTAL AIR MASS
WILL ALLOW FOR LOWERING SNOW LEVELS TUESDAY TO AROUND 4000-5000FT
AMID LIGHTER QPF. THERE, WPC PROBABILITIES FOR AT LEAST 8 INCHES OF
SNOW ARE HIGHEST (>50%). THE STRONGER/COLDER AR WILL PUSH INTO THE
REGION WEDNESDAY THOUGH THE HIGHEST PW/IVT ANOMALIES WILL BE SOUTH
OF THE REGION. NEVERTHELESS, STRONG UPSLOPE FLOW WILL CAPITALIZE
ON AVAILABLE MOISTURE COINCIDENT WITH LOWERING SNOW LEVELS TO BRING
MODEST ACCUMULATING SNOW TO THE PASSES. SNOW LEVELS BY WEDNESDAY
EVENING WILL DROP TO AROUND 2000-2500FT (700MB TEMPS DOWN BELOW
-12C) WITH STILL MODEST QPF OVER THE REGION. INCREASINGLY HEAVIER
SNOW WILL PUSH DOWN THE TERRAIN AND CONTINUE BEYOND THIS FORECAST
PERIOD (00Z THURSDAY). THROUGH THEN, WPC PROBABILITIES FOR AT
LEAST 8 INCHES OF SNOW ARE >50% ABOVE 2500FT OR SO (WHICH INCLUDES
SNOQUALMIE PASS).
MOISTURE SURGE AND BREEZY/WINDY CONDITIONS WILL PROGRESS EASTWARD
INTO THE NORTHERN ROCKIES/DIVIDE WITH WPC PROBABILITIES FOR AT
LEAST 8 INCHES OF SNOW >50% ABOVE 5000FT (NORTH) TO AROUND 8000FT
(SOUTH, OVER WY). WSSI-P IS SHOWING SOME PROBABILITIES OF MODERATE
IMPACTS FROM BLOWING SNOW OVER THE HIGHER ELEVATIONS IN MT INTO WY.
THE PROBABILITY OF SIGNIFICANT ICING IS LESS THAN 10 PERCENT.
FRACASSO
..EXTREME COLD KEY MESSAGES ARE IN EFFECT AND LINKED BELOW
HTTPS://WWW.WPC.NCEP.NOAA.GOV/KEY_MESSAGES/LATESTKEYMESSAGE_1.PNG
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