072
FOUS11 KWBC 192113
QPFHSD
PROBABILISTIC HEAVY SNOW AND ICING DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
413 PM EST WED FEB 19 2025
VALID 00Z THU FEB 20 2025 - 00Z SUN FEB 23 2025
..MID-ATLANTIC AND CAROLINAS
DAY 1...
MAJOR WINTER STORM CONTINUES INTO TONIGHT FOR SOUTHERN MID-
ATLANTIC WITH HEAVY SNOW AND NOTABLE ICING. SEE THE LATEST KEY
MESSAGES LINKED AT THE BOTTOM.
DEVELOPING SURFACE LOW AHEAD OF SOUTHERN STREAM WAVE IS OFF SC/GA
BORDER THIS AFTERNOON. THIS COASTAL LOW STRENGTHENS AS IT SHIFTS
NORTHEAST OFF CAPE HATTERAS THROUGH TONIGHT. HEAVY SNOW BANDS WILL
PERSIST OVER SOUTHEAST VA INTO NORTHEAST NC THROUGH THIS EVENING
WHERE DAY 1 SNOW PROBS FOR AN ADDITIONAL >4" AFTER 00Z ARE 40-70%.
SNOW BANDS SHIFT OFFSHORE AFTER MIDNIGHT. A WINTRY MIX OF MAINLY
FREEZING RAIN WILL PERSIST OVER SOUTHERN AND EASTERN NC THROUGH
THIS EVENING. DAY 1 ICE PROBS FOR AN ADDITIONAL >0.1" AFTER 00Z ARE
40-70% OVER PORTIONS OF THE MHX AND ILM CWAS.
THE NORTHERN STREAM UPPER LOW IS CURRENTLY OVER IOWA AND WILL
TRACK TO OHIO THROUGH TONIGHT BEFORE PUSHING OVER THE NORTHERN MID-
ATLANTIC THURSDAY. GENERALLY LIGHT SNOW IS EXPECTED FROM THIS
UPPER LOW OVER THE OHIO VALLEY TONIGHT AND OVER THE CENTRAL/
SOUTHERN APPALACHIANS INTO THE DC METRO AREA THURSDAY MORNING. DAY
1 SNOW PROBS FOR >2" ARE 40-70% OVER THE WV HIGHLANDS AND THE GREAT
SMOKIES.
..GREAT LAKES/MASSACHUSETTS CAPE AND ISLANDS
DAYS 1-2...
LAKE EFFECT SNOW REINVIGORATES OVER LAKE MICHIGAN TONIGHT INTO
THURSDAY ON THE BACK SIDE OF THE AFOREMENTIONED UPPER LOW. NNWLY
FLOW BRINGS SINGLE BAND LES TO FAR SOUTHWEST MI INTO NORTHERN IN
THROUGH THURSDAY WHERE DAY 1 SNOW PROBS FOR >4" ARE 40-60%. NWLY
FLOW LATE THURSDAY BRINGS LAKE ENHANCED SNOW DOWNWIND OF ERIE
DESPITE THE LAKE BEING NEARLY FROZEN OVER. HOWEVER, FETCH FROM LAKE
HURON WILL AID SNOWFALL. DAY 1.5 SNOW PROBS FOR >4" ARE AROUND 20%
NEAR ERIE, PA.
THE SYSTEM DEVELOPING OFF THE MID-ATLANTIC COAST THURSDAY TRACKS UP
OFF NOVA SCOTIA THURSDAY NIGHT. THIS WILL BRING THE PRECIP SHIELD
WITH BAY/OCEAN ENHANCED SNOW TO SOUTHEASTERN MA/CAPE COD AND
ISLANDS THURSDAY AFTERNOON/EVENING. DAY 1.5 SNOW PROBS FOR >4" ARE
40-70% FOR THE CAPE AND ISLANDS.
..PACIFIC NORTHWEST THROUGH THE CENTRAL ROCKIES
DAYS 1-3...
A POTENT BUT PROGRESSIVE PACIFIC SYSTEM OVER THE PACNW COAST EARLY
THIS AFTERNOON WILL DIG SOUTH AS IT MOVES INLAND WITH THE BASE OF
THE TROUGH REACHING CO BY LATE THURSDAY. SNOW LEVELS DROP TO 3000FT
OVER THE WA CASCADES THROUGH THIS EVENING BEFORE PRECIP CUTS OFF
WITH DAY 1 SNOW PROBS FOR >4" 40-80% AT AND ABOVE PASS LEVEL.
SNOW LEVELS OVER THE NORTHERN ROCKIES ARE AROUND 4000FT AND CLOSER
TO 6000FT OVER CO THROUGH THURSDAY AS THIS TROUGH APPROACHES.
MODERATE ELEVATION SNOW CAN BE EXPECTED WITH DAY 1 SNOW PROBS FOR
>6" 40-80% AROUND THE BITTERROOTS ON THE ID/MT BORDER,
NORTHEASTERN NV RANGES, THE WASATCH, UINTA AND TETONS. SNOW
CONTINUES OVER THE CO ROCKIES THROUGH THURSDAY NIGHT WITH DAY 2
SNOW PROBS FOR >6" 30-60% ACROSS CENTRAL AND NORTHERN CO RANGES.
THE NEXT WAVE PUSHES INTO THE QUEEN CHARLOTTE SOUND FRIDAY EVENING
WITH ANOTHER ATMOSPHERIC RIVER PUSHING ACROSS WA FRIDAY AFTERNOON,
EXPANDING SOUTH THROUGH OR SUNDAY. SNOW LEVELS AT ONSET ARE AROUND
4500FT IN THE WA CASCADES FRIDAY, INCREASING TO 5000FT FRIDAY
NIGHT AND 6000FT OVER WA (AND 8000FT OVER OR) ON SATURDAY. DAY 3
SNOW PROBS FOR >6" ARE 30-40% OVER THE ONLY HIGHER WA CASCADES WITH
THE VERY HIGH SNOW LEVELS OVER OR PRECLUDING SNOW PROBS FOR THE
ISOLATED HIGHER CASCADE PEEKS AT THIS TIME.
JACKSON
..WINTER STORM KEY MESSAGES ARE IN EFFECT AND LINKED
HTTPS://WWW.WPC.NCEP.NOAA.GOV/KEY_MESSAGES/LATESTKEYMESSAGE_2.PNG
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