259  
FXUS01 KWBC 281943  
PMDSPD  
 
SHORT RANGE FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
242 PM EST THU DEC 28 2017  
 
VALID 00Z FRI DEC 29 2017 - 00Z SUN DEC 31 2017  
 
...HEAVY SNOWFALL LIKELY IN THE HIGHER TERRAIN OF THE NORTHERN  
INTERMOUNTAIN WEST AND NORTHERN ROCKIES...  
 
...ARCTIC AIR WILL OVERTAKE MUCH OF THE CENTRAL U.S. BY THIS  
WEEKEND...  
 
A COLD FRONT PUSHING ONSHORE EARLY TOMORROW MORNING IN THE PACIFIC  
NORTHWEST WILL ALLOW FOR WIDESPREAD PRECIPITATION ACROSS MUCH OF  
THE NORTHWEST U.S. AND INTO THE NORTHERN ROCKIES. WINTER WEATHER  
ADVISORIES AND WINTER STORM WARNINGS FROM WASHINGTON TO MONTANA  
ARE HIGHLIGHTING THE POTENTIAL FOR HEAVY SNOWFALL, WITH AS MUCH AS  
2 TO 3 FEET POSSIBLE IN THE HIGHEST TERRAIN OF THE WASHINGTON  
CASCADES AND THE NORTHERN ROCKIES. SOME MINOR FREEZING RAIN  
ACCUMULATIONS ARE ALSO POSSIBLE IN THE LOWER ELEVATIONS OF CENTRAL  
WASHINGTON AND NORTHEAST OREGON. HEAVY RAINFALL CAN BE EXPECTED  
FOR COASTAL REGIONS OF THE PACIFIC NORTHWEST AS WELL.  
 
LIGHT SNOWFALL WILL SPREAD FROM THE DAKOTAS AND THE UPPER MIDWEST  
TOMORROW INTO PARTS OF THE MID-ATLANTIC AND NORTHEAST BY SATURDAY  
AS A CLIPPER TYPE SYSTEM MOVES THROUGH. LIGHT ACCUMULATIONS MAY BE  
POSSIBLE ACROSS PARTS OF THE NORTHERN PLAINS AND UPPER MIDWEST,  
WITH LITTLE TO NO ACCUMULATION EXPECTED AS THE SYSTEM PUSHES INTO  
THE NORTHEAST. WESTERLY FLOW ON THE BACKSIDE OF THE SYSTEM WILL  
ALSO ALLOW FOR CONTINUED LAKE EFFECT SNOWFALL DOWNWIND OF THE  
UPPER AND LOWER GREAT LAKES. SOME MODERATE ACCUMULATIONS ARE  
POSSIBLE. THE BIG STORY WITH THIS FRONT HOWEVER WILL BE A SURGE OF  
VERY COLD ARCTIC AIR PLUNGING SOUTHWARD INTO THE CENTRAL U.S. BY  
THIS WEEKEND. TEMPERATURE ANOMALIES ON SATURDAY COULD BE AS MUCH  
AS 30 TO 35 DEGREES BELOW NORMAL WITH AFTERNOON HIGHS OF BELOW  
ZERO EXPECTED ACROSS PARTS OF THE NORTHERN PLAINS.  
 
MEANWHILE, A WAVY STATIONARY BOUNDARY IN THE GULF OF MEXICO WILL  
KEEP MAINLY LIGHT SHOWERS ACROSS THE GULF COAST AND SOUTHEAST  
STATES THE NEXT COUPLE OF DAYS. MUCH OF THIS SHOULD BE RAINFALL  
BUT A SHALLOW LAYER OF COLD AIR EAST OF THE APPALACHIANS MAY ALLOW  
FOR FREEZING RAIN OR A RAIN/SNOW MIX ACROSS PORTIONS OF GEORGIA  
AND THE CAROLINAS ON FRIDAY.  
 
SANTORELLI  
 
GRAPHICS AVAILABLE AT  
WWW.WPC.NCEP.NOAA.GOV/BASICWX/BASICWX_NDFD.PHP  

 
 
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