679
FXUS01 KWBC 202000
PMDSPD
SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
259 PM EST SAT DEC 20 2025
VALID 00Z SUN DEC 21 2025 - 00Z TUE DEC 23 2025
...ACTIVE PATTERN TO CONTINUE FOR THE WEST COAST WITH HEAVY
RAINFALL AND HIGHER ELEVATION HEAVY SNOW OVER THE NEXT COUPLE OF
DAYS...
...FLOOD POTENTIAL WILL INCREASE ACROSS CENTRAL/NORTHERN
CALIFORNIA ON SUNDAY AND MONDAY WITH SEVERAL INCHES OF RAIN
FORECAST...
...TEMPERATURES WILL BE WELL ABOVE AVERAGE FROM THE INTERMOUNTAIN
WEST INTO THE SOUTHERN TO CENTRAL HIGH PLAINS...
THE JET STREAM WILL GENERALLY BE ORIENTED FROM WEST TO EAST ACROSS
THE LOWER 48 THROUGH EARLY THIS WEEK WHICH WILL KEEP LOCATIONS
FROM CENTRAL CALIFORNIA INTO WESTERN WASHINGTON AND THE INTERIOR
WESTERN U.S. FAIRLY ACTIVE. AN ATMOSPHERIC RIVER WILL TAKE AIM AT
CALIFORNIA WITH HEAVY PRECIPITATION BEGINNING TONIGHT FROM CENTRAL
TO NORTHERN CALIFORNIA. SNOW LEVELS WILL BE FAIRLY HIGH ACROSS THE
SIERRA NEVADA WHICH WILL KEEP THE MAJORITY OF PRECIPITATION IN THE
FORM OF RAIN BELOW ~9,000 FEET THROUGH SUNDAY. BY MONDAY MORNING,
THE ATMOSPHERIC RIVER AND AXIS OF HEAVIEST RAINFALL WILL SHIFT TO
BETWEEN SAN FRANCISCO AND POINT CONCEPTION WITH SNOW LEVELS
FALLING TO ABOUT 6,000 TO 7,000 FEET FOR THE CENTRAL TO NORTHERN
SIERRA NEVADA. LOCALLY HEAVY RAINFALL RATES AND RAINFALL TOTALS
THROUGH MONDAY EVENING OF 5 TO 10 INCHES FOR THE SIERRA NEVADA AND
AT LEAST 3 TO 6 INCHES FOR THE COASTAL RANGES. WHILE THE AXIS OF
HEAVIEST RAINFALL WILL MEANDER NORTH/SOUTH OVER THE NEXT COUPLE OF
DAYS, PERSISTENT RAINFALL WILL BEGIN TO LEAD TO FLOODING OF
SMALLER RIVERS/CREEKS AND INTO URBAN AREAS.
MEANWHILE, LOCATIONS TO THE NORTH, FROM WESTERN OREGON AND WESTERN
WASHINGTON, WILL SEE CONTINUED ONSHORE FLOW BUT COOLER
TEMPERATURES WILL RESULT IN GREATER COVERAGE OF SNOW INTO THE
MOUNTAINS. AT LEAST 1 TO 3 FEET OF ADDITIONAL SNOW IS EXPECTED FOR
THE HIGHER ELEVATIONS OF THE OLYMPICS AND CASCADES. SNOW LEVELS
WILL LOWER WITH NORTHWARD EXTENT AND WILL BE AS LOW AS 1,000 FEET
ABOVE SEA LEVEL AT TIMES FOR WESTERN WASHINGTON.
REGARDING TEMPERATURES, HIGHS ARE EXPECTED TO BE 15 TO 30+ DEGREES
ABOVE AVERAGE FROM PORTIONS OF THE INTERMOUNTAIN WEST INTO THE
CENTRAL HIGH PLAINS THROUGH MONDAY DUE TO THE ONSLAUGHT OF PACIFIC
AIR. SEVERAL DAILY RECORD HIGH TEMPERATURES ARE LIKELY TO BE SET
ACROSS THESE AREAS OVER THE NEXT FEW DAYS AND LIKELY CONTINUING
INTO MID-WEEK.
OTTO
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