788
FXUS01 KWBC 010800
PMDSPD
SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
259 AM EST SAT FEB 01 2025
VALID 12Z SAT FEB 01 2025 - 12Z MON FEB 03 2025
...UNSETTLED WEATHER TO BRING LOWER ELEVATION RAINS AND HEAVY
MOUNTAIN SNOWFALL ACROSS THE PACIFIC NORTHWEST AND THE NORTHERN
ROCKIES GOING THROUGH THE WEEKEND...
...STRONG ATMOSPHERIC RIVER TO BRING HEAVY RAINS AND FLOODING
CONCERNS TO AREAS OF CENTRAL AND NORTHERN CALIFORNIA...
...NEW STORM SYSTEM EJECTING OUT ACROSS THE NORTHERN PLAINS WILL
BRING ACCUMULATING SNOWFALL TO PORTIONS OF THE UPPER MIDWEST,
GREAT LAKES AND NORTHEAST...
A SWITCH TO A VERY UNSETTLED WEATHER PATTERN IS UNDERWAY ACROSS
THE NORTHWEST AND MUCH OF THE WEST COAST AS A MORE ZONAL FLOW
PATTERN UNFOLDS. THIS WILL BRING MOIST ONSHORE PACIFIC FLOW WITH
LOWER ELEVATION RAINS AND INCREASINGLY HEAVY MOUNTAIN SNOWFALL FOR
THE CASCADES AND ALSO THE NORTHERN ROCKIES. GOING THROUGH SUNDAY,
AS MUCH AS 1 TO 3 FEET OF NEW SNOWFALL IS EXPECTED OVER THE HIGH
TERRAIN, AND SNOW LEVELS WILL ACTUALLY BE FALLING WITH TIME AS
COLDER AIR ALSO SETTLES SOUTH FROM SOUTHWEST CANADA. THIS ALLOW
TEMPERATURES TO DROP BELOW NORMAL WITH HIGH TEMPERATURES AS MUCH
AS 5 TO 10+ DEGREES BELOW AVERAGE BY THE END OF THE WEEKEND.
AS UNSETTLED WEATHER IMPACTS THE NORTHWEST, STRONG DEEP LAYER
PACIFIC FLOW ALONG WITH A QUASI-STATIONARY FRONT WILL BECOME
SITUATED OVER CENTRAL AND NORTHERN CALIFORNIA AND THIS WILL SET
THE STAGE FOR A PERSISTENT AND STRONG ATMOSPHERIC RIVER TO IMPACT
THE REGION. HEAVY TO EXCESSIVE RAINFALL IS EXPECTED FOR THE
COASTAL RANGES, INCLUDING AREAS AROUND THE BAY AREA, AND
ESPECIALLY AREAS FARTHER INLAND INTO THE FOOTHILLS AND HIGHER
TERRAIN OF THE NORTHERN SIERRA NEVADA. MULTI-DAY RAINFALL TOTALS
THROUGH SUNDAY FOR THE COASTAL RANGES MAY REACH SEE AS MUCH AS 3
TO 6 INCHES. HOWEVER, FOR THE UPSLOPE AREAS OF THE SIERRA NEVADA,
AS MUCH AS 6 TO 12 INCHES OF RAIN IS FORECAST, AND WITH HIGH SNOW
LEVELS, THERE WILL BE STRONG CONCERNS FOR FLOODING. THIS WILL
INCLUDE A THREAT FOR BURN SCAR FLASH FLOODING/DEBRIS FLOW ACTIVITY
LOCALLY. HEAVY RAINS WILL BE IMPACTING THE SACRAMENTO VALLEY AND
SOME FLOODING WILL BE POSSIBLE HERE AS WELL. THE WEATHER
PREDICTION CENTER HAS DEPICTED A SLIGHT RISK OF EXCESSIVE RAINFALL
ACROSS THE REGION (LEVEL 2 OF 4) TO ADDRESS THE MULTI-DAY FLOODING
CONCERNS ASSOCIATED WITH THIS IMPENDING ATMOSPHERIC RIVER ACTIVITY.
MEANWHILE, A NEW STORM SYSTEM RELATED TO THE UNSETTLED WEATHER
UNFOLDING ACROSS THE WEST WILL BEGIN TO EJECT EAST OUT ACROSS THE
NORTHERN PLAINS LATER SATURDAY THROUGH SATURDAY NIGHT THIS WILL
BRING A THREAT FOR SEVERAL INCHES OF ACCUMULATING SNOW TO THE
UPPER MIDWEST. THIS SYSTEM WILL THEN BEGIN TO LIFT UP INTO
SOUTHEAST CANADA GOING THROUGH SUNDAY, BUT WILL BRING A THREAT FOR
SNOWFALL ALSO ACROSS PORTIONS OF THE GREAT LAKES REGION AND THE
NORTHEAST WHERE THERE WILL BE SUFFICIENT COLD AIR IN PLACE. IN THE
WAKE OF THIS SYSTEM, MUCH COLDER AIR WILL BE SETTLING SOUTHWARD
ACROSS THE NORTHERN PLAINS WHICH WILL ALLOW TEMPERATURES TO BEGIN
RETURNING BACK TO BELOW NORMAL.
ELSEWHERE, VERY MILD TEMPERATURES WITH ABOVE AVERAGE HIGHS CAN BE
EXPECTED ACROSS MUCH OF THE REST OF THE PLAINS REGION AND THE
SOUTH. IN SOME CASES ACROSS THE PLAINS AND MIDWEST, THE
TEMPERATURES THIS WEEKEND WILL BE AS MUCH AS 15 TO 20 DEGREES
ABOVE NORMAL. MANY AREAS OF THE SOUTHEAST AND THE SOUTHWEST WILL
ALSO BE WARMER THAN NORMAL WITH HIGHS AS MUCH AS AVERAGE 5 TO 10+
DEGREES ABOVE AVERAGE.
ORRISON
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