182  
FXUS01 KWBC 202022  
PMDSPD  
 
SHORT RANGE FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
321 PM EST WED DEC 20 2017  
 
VALID 00Z THU DEC 21 2017 - 00Z SAT DEC 23 2017  
   
..HEAVY SNOW OVER PARTS OF THE CENTRAL ROCKIES
 
 
...SNOW POSSIBLE FROM PARTS OF THE NORTHERN PLAINS ACROSS THE  
GREAT LAKES INTO THE NORTHEAST...  
 
...HEAVY RAIN POSSIBLE OVER PARTS OF THE LOWER MISSISSIPPI  
VALLEY/TENNESSEE VALLEY...  
 
STRONG STORM OVER GREAT BASIN/CENTRAL PLAINS WILL LIFT  
NORTHEASTWARD TO THE OHIO VALLEY BY FRIDAY. THE SYSTEM WILL  
PRODUCE COASTAL RAIN AND HIGHER ELEVATION SNOW OVER PARTS OF THE  
PACIFIC NORTHWEST WITH SNOW OVER PARTS OF THE NORTHERN  
INTERMOUNTAIN REGION/NORTHERN ROCKIES AND THE GREAT BASIN. THE  
RAIN AND SNOW WILL COME TO AN END OVER THE PACIFIC  
NORTHWEST/NORTHERN INTERMOUNTAIN REGION OVERNIGHT WEDNESDAY. IN  
ADDITION, SNOW OVER THE NORTHERN PLAINS WILL SPREAD INTO THE UPPER  
GREAT LAKES ALSO OVERNIGHT WEDNESDAY AS SNOW MOVES INTO THE  
CENTRAL ROCKIES ENDING OVERNIGHT THURSDAY. ON THURSDAY, SNOW AND  
SOME RAIN WILL DEVELOP OVER PARTS OF THE NORTHERN/CENTRAL PLAINS  
INTO THE UPPER GREAT LAKES. OVERNIGHT THURSDAY, SNOW WILL MOVE  
INTO THE NORTHEAST WHILE RAIN MOVES INTO PARTS OF THE OHIO VALLEY  
AND PARTS OF THE NORTHERN MID-ATLANTIC BY FRIDAY MORNING. THE  
ASSOCIATED WARM FRONT WILL BE DAMMED UP AGAINST THE APPALACHIANS  
THURSDAY AFTERNOON INTO FRIDAY. WITH THE DAMMING, THERE IS A RISK  
OF RAIN/FREEZING RAIN MAY DEVELOP OVER PARTS OF THE LOWER GREAT  
LAKES/NORTHERN APPALACHIANS ALSO OVERNIGHT THURSDAY INTO FRIDAY.  
ADDITIONALLY, AS THE ASSOCIATED COLD FRONT MOVES FROM THE PLAINS  
INTO PARTS OF THE MISSISSIPPI VALLEY, MOISTURE FROM THE GULF OF  
MEXICO WILL FLOW NORTHEASTWARD OVER THE SOUTHERN PLAINS INTO THE  
LOWER MISSISSIPPI/TENNESSEE VALLEYS ON THURSDAY AFTERNOON INTO  
FRIDAY. LIKEWISE, OVERNIGHT THURSDAY INTO FRIDAY, SHOWERS AND  
THUNDERSTORMS WILL DEVELOP OVER PARTS OF THE SOUTHERN PLAINS INTO  
THE LOWER MISSISSIPPI/TENNESSEE VALLEYS.  
 
MEANWHILE, UPPER-LEVEL ENERGY OVER THE SOUTHERN  
APPALACHIANS/SOUTHEAST WILL MOVE EASTWARD OUT OVER THE WESTERN  
ATLANTIC WENDESDAY EVENING INTO THURSDAY MORNING. THE SYSTEM WILL  
PRODUCE RAIN AND THUNDERSTORMS OVER PARTS OF THE SOUTHERN OHIO  
VALLEY, TENNESSEE VALLEY, SOUTHERN MID-ATLANTIC, SOUTHEAST AND  
EASTERN GULF COAST THAT WILL MOVE EASTWARD OFF THE SOUTHEAST COAST  
BY THURSDAY MORNING INTO AFTERNOON.  
 
MORE TO FOLLOW  
 
 
ZIEGENFELDER  
 
GRAPHICS AVAILABLE AT  
WWW.WPC.NCEP.NOAA.GOV/BASICWX/BASICWX_NDFD.PHP  

 
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab HPC Page Main Text Page