428
FXUS01 KWBC 170757
PMDSPD
SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
257 AM EST TUE DEC 17 2024
VALID 12Z TUE DEC 17 2024 - 12Z THU DEC 19 2024
...ANOTHER ATMOSPHERIC RIVER TO BRING HEAVY COASTAL RAINS AND HIGH
ELEVATION MOUNTAIN SNOW TO THE NORTHWEST...
...UNSETTLED, WET WEATHER EXPECTED FOR MOST OF THE EASTERN U.S.
WEDNESDAY...
...PERIODS OF SNOW FOR THE NORTHERN PLAINS THROUGH MID-WEEK WITH
HEAVIER ACCUMULATIONS MOST LIKELY WEDNESDAY NIGHT...
...MUCH ABOVE AVERAGE TEMPERATURES EXPECTED FOR MOST OF THE LOWER
48 INTO MID-WEEK...
YET ANOTHER PACIFIC SYSTEM WILL HELP TO USHER IN A WAVE OF PACIFIC
MOISTURE/ATMOSPHERIC RIVER INTO THE PACIFIC NORTHWEST AND INLAND
OVER THE NORTHERN GREAT BASIN/ROCKIES TUESDAY. A MORE NORTHERLY
TRACK WILL HELP TO FOCUS THE HEAVIEST LOWER ELEVATION RAINFALL
ALONG THE COASTAL RANGES OF NORTHERN OREGON AND WASHINGTON STATE,
WITH HEAVY HIGH ELEVATION MOUNTAIN SNOW FOR THE NORTHERN CASCADES.
SOME MODERATE SNOW ACCUMULATIONS WILL ALSO BE POSSIBLE INTO THE
NORTHERN GREAT BASIN AND NORTHERN/CENTRAL ROCKIES, AIDED IN PART
BY A LEADING WAVE DEPARTING THE REGION EARLY THIS MORNING. LOWER
ELEVATION INLAND LOCATIONS CAN EXPECT A WINTRY MIX OF RAIN AND
SNOW, WITH SOME FREEZING RAIN POSSIBLE TO THE EAST OF THE CASCADES
IN WASHINGTON. PRECIPITATION CHANCES SHOULD COME DOWN THROUGH THE
DAY WEDNESDAY FOR THE PACIFIC NORTHWEST WHILE LINGERING LONGER IN
THE NORTHERN ROCKIES.
A LINGERING FRONTAL BOUNDARY WILL HELP TO TRIGGER SOME SHOWERS AND
THUNDERSTORMS OVER PORTIONS OF THE SOUTHERN PLAINS EAST INTO THE
LOWER MISSISSIPPI, TENNESSEE, AND OHIO VALLEYS THROUGH THE DAY
TUESDAY. AN APPROACHING UPPER-LEVEL WAVE WILL HELP TO REINFORCE
THE BOUNDARY OVERNIGHT TUESDAY AND ENHANCE MOIST, SOUTHERLY FLOW
FROM THE GULF, LEADING TO INCREASING STORM COVERAGE AND LOCALLY
HEAVY RAINFALL. THE BOUNDARY WILL PUSH EASTWARD AS A COLD FRONT
TOWARDS THE EAST COAST THROUGH THE DAY WEDNESDAY SPREADING SHOWERS
AND STORMS INTO THE SOUTHEAST AND COASTAL NORTHEAST. COLDER AIR IN
PLACE TO THE NORTH OVER THE INTERIOR NORTHEAST WILL LEAD TO SNOW
SHOWERS WITH SOME LIGHT TO MODERATE ACCUMULATIONS FOR HIGHER
MOUNTAIN ELEVATIONS.
A QUICK MOVING UPPER-LEVEL WAVE WILL BRING SOME SNOW SHOWERS TO
PORTIONS OF THE NORTHERN PLAINS/UPPER MIDWEST TODAY WITH SOME
LIGHT ACCUMULATIONS POSSIBLE, ESPECIALLY FROM CENTRAL SOUTH DAKOTA
EAST THROUGH SOUTHERN MINNESOTA. THESE LIGHT SNOW SHOWERS WILL
SPREAD EASTWARD INTO THE GREAT LAKES WEDNESDAY. THEN, ANOTHER MORE
POTENT WAVE WILL APPROACH FROM THE WEST DURING THE DAY WEDNESDAY
LEADING TO LEE CYCLOGENESIS OVER THE NORTHERN HIGH PLAINS AND
HELPING TO CONSOLIDATE/STRENGTHEN A SURFACE FRONTAL SYSTEM. THIS
WILL LEAD TO ENHANCED LIFT OVER THE NORTHERN PLAINS AND A QUICK
DEVELOPING AND POTENTIALLY INTENSE BAND OF SNOWFALL BY WEDNESDAY
EVENING. SNOW TOTALS OF 2-4" CAN BE EXPECTED WITH LOCALLY HEAVIER
AMOUNTS POSSIBLE THROUGH THURSDAY MORNING. SOME MIXED
PRECIPITATION WITH LIGHT ICE ACCUMULATIONS WILL BE POSSIBLE AS
WELL.
ELSEWHERE, PERSISTENT SHOWER AND THUNDERSTORM CHANCES WILL
CONTINUE FOR FLORIDA, PARTICULARLY ALONG THE ATLANTIC COAST. SOME
INTENSE DOWNPOURS WILL BE POSSIBLE TUESDAY WITH AN ISOLATED THREAT
OF SOME FLOODING IN THE URBAN AREAS OF SOUTH FLORIDA. MOST OF THE
COUNTRY WILL CONTINUE TO SEE WELL ABOVE AVERAGE TEMPERATURES
THROUGH AT LEAST MID-WEEK. FORECAST HIGHS TUESDAY RANGE FROM THE
40S AND 50S IN THE INTERIOR WEST AND NEW ENGLAND; THE 50S AND 60S
FOR THE WEST COAST, CENTRAL PLAINS, OHIO VALLEY, AND MID-ATLANTIC;
AND 60S AND 70S FOR THE SOUTHWEST, SOUTHERN PLAINS, AND SOUTHEAST.
A COLD FRONT WILL BRING SOME COOLER, MORE SEASONABLE TEMPERATURES
TO THE PLAINS WEDNESDAY AS HIGHS FALL INTO THE 40S AND 50S. ONE
REGION THAT WILL REMAIN MUCH COLDER WILL BE THE NORTHERN
PLAINS/UPPER MIDWEST, WITH MOST HIGHS ONLY INTO THE TEENS AND 20S.
PUTNAM
GRAPHICS AVAILABLE AT
HTTPS://WWW.WPC.NCEP.NOAA.GOV/BASICWX/BASICWX_NDFD.PHP
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page