660  
FXUS01 KWBC 150643  
PMDSPD  
 
SHORT RANGE FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
142 AM EST SAT DEC 15 2018  
 
VALID 12Z SAT DEC 15 2018 - 12Z MON DEC 17 2018  
 
...STRONG STORM SYSTEMS FOR BOTH THE WEST COAST AND EAST COAST  
THIS WEEKEND...  
 
THERE WILL BE TWO MAIN WEATHER FEATURES OF INTEREST THROUGH THE  
WEEKEND. THE FIRST WILL BE A DEEP AND VERTICALLY STACKED LOW  
PRESSURE SYSTEM SLOWLY TRACKING ACROSS THE SOUTHEASTERN UNITED  
STATES, WITH SECONDARY CYCLOGENESIS EXPECTED TO OCCUR NEAR THE  
MID-ATLANTIC COAST BY SUNDAY MORNING. THE RESULT WILL BE COPIOUS  
AMOUNTS OF RAINFALL FROM THE SOUTHEAST COAST AND OHIO VALLEY TO  
SOUTHERN NEW ENGLAND. IN FACT, THE RAINFALL FROM THIS EVENT ALONE  
WILL BE ENOUGH FOR SOME CITIES ACROSS THE EAST COAST REGION TO  
ESTABLISH NEW ANNUAL RAINFALL RECORDS, INCLUDING WASHINGTON, D.C.  
GIVEN THE WARMER NATURE OF THIS STORM SYSTEM, ANY WINTER WEATHER  
SHOULD BE RELEGATED TO THE HIGHER ELEVATIONS OF INTERIOR SOUTHERN  
NEW ENGLAND AND ALL RAIN FOR THE MAJOR CITIES ALONG THE INTERSTATE  
95 CORRIDOR.  
 
THE SECOND AREA OF INTEREST WILL BE THE WEST COAST STATES AS A  
POWERFUL PACIFIC STORM SYSTEM APPROACHES THE COAST SATURDAY NIGHT.  
THE EXTREMELY STRONG SURFACE LOW IS FORECAST TO WEAKEN AS IT  
TRACKS ACROSS THE GULF OF ALASKA. HOWEVER, THE TRAILING COLD  
FRONT WILL HAVE ENOUGH OF A PRESSURE GRADIENT WITH IT TO GENERATE  
STRONG WINDS AND HIGH WAVES FROM NORTHERN CALIFORNIA TO WESTERN  
WASHINGTON, AND VARIOUS WIND AND SURF RELATED BULLETINS HAVE BEEN  
ISSUED REGARDING THESE HAZARDS. HEAVY RAIN AND HIGH MOUNTAIN SNOW  
ARE ALSO EXPECTED AS THE FRONT MOVES INLAND, PARTICULARLY FOR  
NORTHERN CALIFORNIA AND NORTHWEST WASHINGTON.  
 
ELSEWHERE ACROSS THE CONTINENTAL U.S., SUNNY TO PARTLY CLOUDY  
CONDITIONS ARE EXPECTED FROM THE ROCKIES TO THE MISSISSIPPI RIVER  
AS AN EXPANSIVE HIGH PRESSURE RIDGE GOVERNS THE WEATHER PATTERN  
THROUGH THE WEEKEND. OVERALL, TEMPERATURES ARE EXPECTED TO BE  
NEAR TO ABOVE AVERAGE FOR THE MAJORITY OF THE CONTINENTAL U.S.  
THROUGH MONDAY MORNING WITH NO MAJOR INCURSIONS OF ARCTIC AIR  
MASSES EXPECTED.  
 
D. HAMRICK  
 
GRAPHICS AVAILABLE AT  
WWW.WPC.NCEP.NOAA.GOV/BASICWX/BASICWX_NDFD.PHP  

 
 
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