468
FXUS01 KWBC 020759
PMDSPD
SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
259 AM EST SAT DEC 02 2023
VALID 12Z SAT DEC 02 2023 - 12Z MON DEC 04 2023
...A MULTI-DAY ATMOSPHERIC RIVER EVENT WILL IMPACT THE NORTHWEST
WITH SIGNIFICANT MOUNTAIN SNOWFALL AND HEAVY RAIN THIS WEEKEND...
...UNSETTLED WEATHER FORECAST ACROSS THE EASTERN THIRD OF THE
COUNTRY WITH HEAVY RAIN POTENTIAL ALONG THE GULF COAST AND
SOUTHEAST; WINTRY WEATHER IS EXPECTED FROM PARTS OF THE MIDWEST
AND GREAT LAKES TO NORTHERN NEW ENGLAND...
...GENERALLY MILDER THAN NORMAL TEMPERATURES EXPECTED FOR ACROSS
MOST OF THE LOWER 48...
THE FIRST WEEKEND OF DECEMBER IS SHAPING UP TO BE AN ACTIVE ONE IN
THE WEST THANKS TO A SERIES OF ATMOSPHERIC RIVERS DIRECTING
COPIOUS AMOUNTS OF PACIFIC MOISTURE INTO THE PACIFIC NORTHWEST AND
THE ROCKIES. THE NEXT STORM IN A SERIES OF STORM SYSTEMS ARRIVED
THIS MORNING, INFLICTING MORE HEAVY MOUNTAIN SNOW IN THE OLYMPICS
AND CASCADES THAT WILL CONTINUE THROUGHOUT THE DAY. MEANWHILE, THE
SAME MOISTURE SOURCE WILL PUSH INLAND TOWARDS THE ROCKIES SATURDAY
AND INTO SATURDAY NIGHT. AS A RESULT, HEAVY MOUNTAIN SNOW IS ON
TAP FROM EASTERN OREGON AND THE NORTHERN ROCKIES ON SOUTH TO THE
WASATCH RANGE IN UTAH AND THE COLORADO ROCKIES. BY SUNDAY, THE
NEXT STORM SYSTEM WILL TRACK FARTHER NORTH TOWARDS BRITISH
COLUMBIA. THIS STORM SYSTEM'S WARM FRONT LIFTS NORTH THROUGH
WESTERN WASHINGTON AND OREGON ON SUNDAY, FORCING SNOW LEVELS TO
RISE SHARPLY AND FORCE MOST OF THE CASCADES AND OLYMPICS TO SWITCH
OVER TO HEAVY RAIN. THIS COMBINATION OF HEAVY RAIN ATOP A DEEP
SNOWPACK MAY LEAD TO MINOR AND MODERATE RIVER FLOODING, AS WELL AS
POSSIBLE FLASH FLOODING, INTO EARLY NEXT WEEK. WPC HAS ISSUED A
SLIGHT RISK FOR EXCESSIVE RAINFALL ON SUNDAY FOR PORTIONS OF
WESTERN OREGON, WHILE A MARGINAL RISK EXTENDS NORTH FROM THE FAR
NORTHERN CALIFORNIA COAST TO WASHINGTON'S CASCADE AND OLYMPIC
RANGES. AS MUCH AS 5 TO 10 INCHES OF RAINFALL ARE FORECAST ALONG
THE COAST OF OREGON, WHILE AS MUCH AS SEVERAL FEET OF SNOW
ACCUMULATE IN THE HIGHER TERRAIN AND PASSES OF THE CASCADES. THE
NORTHERN AND CENTRAL ROCKIES CAN ALSO EXPECT HEAVY SNOW WITH SOME
AREAS SEEING 1-3 FEET THROUGH THE WEEKEND. THE WINTER STORM
SEVERITY INDEX (WSSI) SHOWS MAJOR IMPACTS ARE POSSIBLE IN THE
HIGHEST ELEVATIONS OF THE PACIFIC NORTHWEST AND THE ROCKIES,
LIKELY CAUSING HAZARDOUS TO EVEN IMPOSSIBLE TRAVEL CONDITIONS IN
THESE IMPACTED AREAS.
FARTHER EAST, A PAIR OF STORM SYSTEMS WILL LEAD TO WET AND WINTRY
WEATHER ACROSS PORTIONS THE EASTERN THIRD OF THE CONUS. ALONG THE
GULF COAST, LOW PRESSURE TAPPING INTO RICH GULF OF MEXICO MOISTURE
IS SET TO IGNITE STRONG-TO-SEVERE THUNDERSTORMS FROM SOUTHERN
LOUISIANA TO THE FLORIDA PANHANDLE. THERE ARE SLIGHT RISKS FOR
BOTH SEVERE STORMS AND EXCESSIVE RAINFALL IN PORTIONS OF THESE
AREAS TODAY WITH SEVERE STORMS MORE LIKELY TO CONTAIN DAMAGING
WIND GUSTS AND/OR TORNADOES. FARTHER NORTH, SHOWERS WILL ENVELOPE
THE MID-ATLANTIC AND BOTH THE OHIO AND TENNESSEE VALLEYS SATURDAY
AFTERNOON AND INTO SATURDAY NIGHT. BY SUNDAY MORNING, A NEW STORM
SYSTEM TRACKING INTO THE GREAT LAKES WILL BE RESPONSIBLE FOR
PERIODS OF LIGHT RAIN AND SNOW FROM THE MIDWEST TO THE NORTHERN
GREAT LAKES. FARTHER EAST, ANOTHER DEVELOPING AREA OF LOW PRESSURE
ALONG THE NORTHEAST COAST LOOKS TO FORM AND PRODUCE PERIODS OF
RAIN ALONG THE I-95 CORRIDOR DURING THE DAY ON SUNDAY. IN NORTHERN
NEW ENGLAND, PRECIPITATION WILL FALL IN THE FORM OF SNOW SUNDAY
AFTERNOON AND INTO SUNDAY NIGHT. SNOW LOOKS TO FALL HEAVILY AT
TIMES IN THE ADIRONDACKS, THE GREEN AND WHITE MOUNTAINS, AND INTO
NORTHERN MAINE. LATEST WPC PROBABILISTIC FORECASTS SHOWS A HIGH
CHANCE (GREATER THAN 70%) FOR SNOWFALL TOTALS OVER 6 INCHES
THROUGH SUNDAY NIGHT FROM CENTRAL NEW HAMPSHIRE TO BOTH NORTHERN
AND CENTRAL MAINE. THE LATEST WSSI SHOWS MODERATE IMPACTS FROM
EAST-CENTRAL NEW HAMPSHIRE INTO CENTRAL MAINE, INDICATING SNOWFALL
HERE WILL BE CAPABLE OF CAUSING DISRUPTIONS TO DAILY LIFE. THIS
INCLUDES HAZARDOUS DRIVING CONDITIONS AND POTENTIAL CLOSURES AND
TRAVEL DELAYS.
TEMPERATURE-WISE, MUCH OF THE LOWER 48 WILL WITNESS SEASONAL TO
MILDER THAN NORMAL CONDITIONS, PARTICULARLY EAST OF THE ROCKIES.
THE COOLEST TEMPERATURES VERSUS NORMAL WILL BE EXPERIENCED IN THE
ROCKIES. BACK IN THE SOUTHEAST, RECORD WARM MORNING LOWS ARE
FORECAST FROM SOUTH FLORIDA TO THE MID-ATLANTIC COAST ON SUNDAY.
MULLINAX
GRAPHICS AVAILABLE AT
HTTPS://WWW.WPC.NCEP.NOAA.GOV/BASICWX/BASICWX_NDFD.PHP
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page