927  
FXUS01 KWBC 241853  
PMDSPD  
 
SHORT RANGE FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
152 PM EST MON DEC 24 2018  
 
VALID 00Z TUE DEC 25 2018 - 00Z THU DEC 27 2018  
 
...HEAVY MOUNTAIN SNOWS LIKELY ACROSS THE SIERRAS, CENTRAL GREAT  
BASIN, AND SOUTHERN ROCKIES...  
 
...LOCALLY HEAVY RAINFALL POSSIBLE ACROSS PARTS OF THE NORTHERN  
CALIFORNIA WITH FLASH FLOODING A THREAT MAINLY OVER BURN SCAR  
AREAS...  
 
...POST-CHRISTMAS WINTER STORM TO BRING HEAVY SNOW TO THE NORTH,  
HEAVY RAIN/STRONG THUNDERSTORMS TO THE SOUTH, AND POTENTIAL TRAVEL  
TROUBLES ACROSS PARTS OF THE CENTRAL U.S. BEGINNING WEDNESDAY...  
 
A VIGOROUS UPPER LEVEL SYSTEM PUSHING INTO NORTHERN CALIFORNIA  
THIS EVENING WILL DROP SOUTHWARD THE NEXT FEW DAYS THROUGH THE  
CENTRAL GREAT BASIN AND INTO THE SOUTHWEST. THIS SYSTEM WILL  
SPREAD RAIN ACROSS THE LOWER ELEVATIONS OF CALIFORNIA TONIGHT AND  
INTO THE SOUTHWEST ON CHRISTMAS DAY. LOCALLY HEAVY RAINFALL IS  
POSSIBLE, ESPECIALLY ACROSS PARTS OF NORTHERN CALIFORNIA TONIGHT  
WHERE FLASH FLOODING IS A CONCERN MAINLY OVER HIGHLY SUSCEPTIBLE  
BURN SCAR AREAS. THIS SAME SYSTEM WILL BRING HEAVY MOUNTAIN  
SNOWFALL FROM THE CALIFORNIA SIERRA MOUNTAINS INTO THE HIGHER  
TERRAIN OF THE CENTRAL GREAT BASIN AND PARTS OF THE CENTRAL AND  
SOUTHERN ROCKIES BY WEDNESDAY. AS MUCH AS A FOOT OR MORE OF SNOW  
IS POSSIBLE IN THE HIGHEST ELEVATIONS WITH WINTER STORM WARNINGS  
AND WINTER WEATHER ADVISORIES IN EFFECT FOR MANY OF THESE  
LOCATIONS.  
 
AS THIS SYSTEM EMERGES INTO THE PLAINS TOWARDS THE END OF THE  
SHORT RANGE, A SIGNIFICANT WINTER STORM IS LIKELY TO DEVELOP  
ACROSS THE CENTRAL U.S. BY WEDNESDAY. HEAVY AND ACCUMULATING  
SNOWFALL LOOKS TO BEGIN ON WEDNESDAY AFTERNOON AND EVENING ACROSS  
PARTS OF THE NORTHERN AND CENTRAL PLAINS, SPREADING EASTWARD INTO  
THE UPPER MIDWEST AND GREAT LAKES BEYOND THE SHORT RANGE PERIOD.  
WITH PLENTY OF INSTABILITY IN PLACE ALONG WITH AMPLE GULF MOISTURE  
STREAMING NORTHWARD AHEAD OF THE ATTENDANT COLD FRONT, HEAVY  
RAINFALL AND STRONG TO POTENTIALLY SEVERE THUNDERSTORMS ARE ALSO  
POSSIBLE IN THE WARM SECTOR ACROSS THE SOUTHERN PLAINS. BOTH WPC  
AND SPC HAVE SLIGHT RISKS FOR EXCESSIVE RAINFALL AND SEVERE  
THUNDERSTORMS, RESPECTIVELY, ACROSS PARTS OF THIS REGION FOR  
WEDNESDAY INTO THURSDAY. THIS STORM IS LIKELY TO MAKE  
POST-CHRISTMAS TRAVEL VERY DIFFICULT, IF NOT IMPOSSIBLE, ACROSS  
PARTS OF THE MIDDLE PART OF THE NATION BEGINNING ON WEDNESDAY.  
 
ELSEWHERE, SOME LIGHT SNOW IS POSSIBLE ACROSS ACROSS PARTS OF THE  
GREAT LAKES AND THE OHIO VALLEY TONIGHT INTO TUESDAY IN  
ASSOCIATION WITH A PAIR OF WEAK SYSTEMS IN THE UPPER LEVELS.  
REGARDING TEMPERATURES IN THE SHORT RANGE, CHRISTMAS DAY LOOKS TO  
BE WARMER THAN AVERAGE EAST OF THE ROCKIES AND AHEAD OF THE  
APPROACHING WINTER STORM. IN THE WEST, TEMPERATURES DROP TO BELOW  
AVERAGE TUESDAY AND WEDNESDAY, WITH AFTERNOON HIGHS AS MUCH AS 10  
TO 20 DEGREES BELOW NORMAL ACROSS PARTS OF THE SOUTHWEST.  
 
SANTORELLI  
 
GRAPHICS AVAILABLE AT  
WWW.WPC.NCEP.NOAA.GOV/BASICWX/BASICWX_NDFD.PHP  

 
 
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