562  
FXUS01 KWBC 202025  
PMDSPD  
 
SHORT RANGE FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
309 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  
TEMPORARILY 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 ARE LIKELY TO BRING 5  
TO 10 INCHES OF RAIN 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 THROUGH MONDAY  
NIGHT. 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, LIKELY CONTINUING INTO  
MID-WEEK.  
 
OTTO  
 
GRAPHICS AVAILABLE AT  
HTTPS://WWW.WPC.NCEP.NOAA.GOV/BASICWX/BASICWX_NDFD.PHP  
 
 
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