133  
FXUS01 KWBC 232111  
PMDSPD  
 
SHORT RANGE FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
411 PM EST SAT DEC 23 2017  
 
VALID 00Z SUN DEC 24 2017 - 00Z TUE DEC 26 2017  
 
...HEAVY SNOW POSSIBLE OVER PARTS OF THE NORTHEAST AND THE UPPER  
GREAT LAKES...  
 
...SNOW POSSIBLE FOR PART OF THE CASCADES AND THE NORTHERN/CENTRAL  
ROCKIES...  
 
...SNOW, RAIN, AND FREEZING RAIN MIXED OVER PARTS OF THE  
NORTHEAST...  
 
LOW PRESSURE OVER NORTHERN NEW ENGLAND WILL MOVE NORTHEASTWARD  
INTO THE CANADIAN MARITIMES BY SUNDAY MORNING, CHRISTMAS EVE,  
WHILE AN AREA OF LOW DEVELOPS OVER THE SOUTHEAST. SNOW, RAIN, AND  
FREEZING RAIN, MIXED WILL DEVELOP OVER PARTS OF NORTHERN NEW  
ENGLAND ON SATURDAY EVENING THAT WILL CHANGE OVER TO AREAS OF RAIN  
AND SNOW OVERNIGHT SATURDAY. THESE AREAS OF RAIN/SNOW WILL COME  
TO AN END OVER THE NORTHEAST BY SUNDAY MORNING. SNOW WILL ALSO  
DEVELOP OVER PARTS OF THE LOWER GREAT LAKES/EASTERN OHIO VALLEY  
THAT WILL WANE BY LATE SATURDAY NIGHT. IN ADDITION, RAIN WILL  
DEVELOP OVER SOUTHERN NEW ENGLAND INTO THE NORTHERN MID-ATLANTIC  
THAT WILL, LIKEWISE, END BY SUNDAY MORNING. RAIN AND A FEW  
EMBEDDED THUNDERSTORMS WILL DEVELOP ALONG THE ASSOCIATED FRONT  
OVER PARTS OF THE SOUTHERN MID-ATLANTIC/SOUTHEAST THAT WILL MOVE  
OFF THE COAST SUNDAY AFTERNOON INTO SUNDAY EVENING ON CHRISTMAS  
EVE.  
 
MEANWHILE, UPPER-LEVEL ENERGY OVER THE NORTHERN ROCKIES WILL MOVE  
SOUTHEASTWARD TO THE SOUTHERN OHIO VALLEY BY SUNDAY EVENING THAT  
WILL BEGIN TO MOVE OFF THE NORTHEAST COAST BY CHRISTMAS MORNING,  
MONDAY MORNING. THE ENERGY WILL AID IN DEVELOPING LOW PRESSURE  
OVER THE OHIO VALLEY BY SUNDAY AFTERNOON INTO EVENING THAT WILL  
MERGE WITH A WAVE OF LOW PRESSURE OVER THE SOUTHEAST FORMING A  
DEEP LOW OVER THE GULF OF MAINE ON CHRISTMAS MORNING, MONDAY  
MORNING. THE ENERGY WILL AID IN PRODUCING SNOW OVER PARTS OF THE  
CENTRAL ROCKIES/CENTRAL PLAINS THAT WILL MOVE INTO THE CENTRAL  
PLAINS/MIDDLE MISSISSIPPI VALLEY BY SUNDAY MORNING THAT IN TURN  
WILL EXPAND INTO THE GREAT LAKES AND OHIO/TENNESSEE VALLEYS BY  
SUNDAY EVENING. THE SNOW WILL MOVE INTO THE NORTHEAST BY  
CHRISTMAS MORNING, MONDAY, WITH THE SNOW HEAVY AT TIMES.  
ADDITIONALLY, RAIN WILL BEGIN TO DEVELOP OVER PARTS OF THE  
TENNESSEE VALLEY SUNDAY AFTERNOON THAT WILL EXPAND INTO THE  
CENTRAL APPALACHIANS BY SUNDAY EVENING. THE RAIN WILL CHANGE OVER  
TO SNOW OVER THE CENTRAL APPALACHIANS OVERNIGHT SUNDAY. ALSO  
OVERNIGHT SUNDAY, RAIN WILL DEVELOP OVER NORTHERN MID-ATLANTIC  
COAST MOVING INTO PARTS OF SOUTHERN NEW ENGLAND BY MONDAY MORNING,  
CHRISTMAS.  
 
A FRONT OVER SOUTH-CENTRAL CANADA WILL MOVE SOUTHWARD TO THE GREAT  
LAKES TO CENTRAL PLAINS/CENTRAL HIGH PLAINS BY CHRISTMAS MORNING,  
MONDAY. SNOW WILL DEVELOP ALONG THE FRONT FROM THE UPPER GREAT  
LAKES TO PARTS OF THE NORTHERN HIGH PLAINS THAT WILL TAPER OFF TO  
TO LAKE EFFECT SNOW OVER THE UPPER GREAT LAKES BY MONDAY MORNING,  
CHRISTMAS. ELSEWHERE, A FRONT OVER THE EASTERN PACIFIC WILL MOVE  
ONSHORE OVER THE PACIFIC NORTHWEST THAT WILL DISSIPATE OVER THE  
GREAT BASIN BY MONDAY, CHRISTMAS. THE SYSTEM WILL PRODUCE RAIN  
AND HIGHER ELEVATION SNOW OVER PARTS OF THE PACIFIC NORTHWEST ON  
SUNDAY AFTERNOON THAT WILL EXPAND INTO THE NORTHERN/CENTRAL  
ROCKIES AS SNOW OVERNIGHT SUNDAY INTO MONDAY.  
 
ZIEGENFELDER  
 
GRAPHICS AVAILABLE AT  
WWW.WPC.NCEP.NOAA.GOV/BASICWX/BASICWX_NDFD.PHP  

 
 
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