946  
FXUS01 KWBC 170736  
PMDSPD  
 
SHORT RANGE FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
235 AM EST SAT NOV 17 2018  
 
VALID 12Z SAT NOV 17 2018 - 12Z MON NOV 19 2018  
 
...SNOW POSSIBLE OVER PARTS OF THE UPPER GREAT LAKES, CENTRAL  
ROCKIES, MIDDLE MISSISSIPPI VALLEY, AND THE NORTHERN MID-ATLANTIC  
INTO PARTS OF NEW ENGLAND...  
 
...AIR STAGNATION AND AIR QUALITY ALERTS CONTINUE TO BE IN EFFECT  
FOR PARTS OF THE PACIFIC NORTHWEST AND CALIFORNIA...  
 
A FRONT OVER PARTS OF THE GREAT LAKES WILL MOVE EASTWARD OFF THE  
NORTHEAST COAST OVERNIGHT SATURDAY. THE SYSTEM WILL AID IN  
PRODUCING LIGHT SNOW OVER PARTS OF THE LOWER GREAT LAKES/MIDDLE  
MISSISSIPPI VALLEY INTO PARTS OF THE NORTHEAST, ENDING OVERNIGHT  
SATURDAY FROM WEST TO EAST. IN THE WAKE OF THE FRONT, LAKE EFFECT  
SNOW WILL DEVELOP OVER PARTS OF THE UPPER GREAT LAKES THROUGH  
SATURDAY NIGHT. ANOTHER FRONT SINKING SOUTHWARD FROM CENTRAL  
CANADA WILL MOVE INTO THE NORTHERN TIER STATE INTO THE UPPER GREAT  
LAKES SUNDAY EVENING INTO MONDAY. LIGHT SNOW WILL RETURN TO THE  
PARTS OF THE UPPER GREAT LAKES SUNDAY AFTERNOON INTO MONDAY AS  
ANOTHER AREA OF LIGHT SNOW DEVELOPS OVER PARTS OF NORTHERN PLAINS  
SUNDAY EVENING INTO MONDAY.  
 
A THIRD FRONT EXTENDING FROM THE MIDDLE MISSISSIPPI VALLEY TO THE  
SOUTHERN ROCKIES WILL MOVE EASTWARD TO THE OHIO VALLEY/CENTRAL  
APPALACHIANS BY SUNDAY EVENING. AREAS OF RAIN AND SNOW WILL  
DEVELOP OVER PARTS OF THE CENTRAL PLAINS INTO THE WESTERN OHIO  
VALLEY BY SATURDAY AFTERNOON THAT WILL MOVE EASTWARD INTO THE  
LOWER GREAT LAKES/OHIO VALLEY BY SUNDAY AFTERNOON. THE AREA OF  
RAIN AND SNOW WILL MOVE INTO PARTS OF THE NORTHERN  
MID-ATLANTIC/SOUTHERN NEW ENGLAND BY OVERNIGHT SUNDAY. BY SUNDAY  
AFTERNOON THE RAIN AND SNOW OVER THE OHIO VALLEY/MIDDLE  
MISSISSIPPI VALLEY WILL TURN OVER TO ALL RAIN AND CONTINUE INTO  
OVERNIGHT SUNDAY.  
 
FURTHERMORE, MOISTURE MOVING NORTHWARD OUT OF THE WESTERN GULF OF  
MEXICO WILL AID IN PRODUCING SHOWERS AND THUNDERSTORMS OVER PARTS  
OF THE WESTERN GULF COAST OVERNIGHT SATURDAY THROUGH SUNDAY NIGHT.  
IN THE MEANTIME, ARCTIC HIGH PRESSURE OVER THE NORTHERN HIGH  
PLAINS WILL MOVE SOUTHEASTWARD TO THE CENTRAL PLAINS BY SUNDAY  
AFTERNOON. UPSLOPE FLOW ASSOCIATED WITH THE CLOCKWISE CIRCULATION  
AROUND THE HIGH PRESSURE WILL AID IN PRODUCING SNOW OVER PARTS OF  
THE CENTRAL ROCKIES ON SATURDAY MORNING ENDING BY SATURDAY  
EVENING. THE ARCTIC HIGH WILL LEAD TO TEMPERATURES NEARLY 25  
DEGREES BELOW AVERAGE OVER THE NORTHERN/CENTRAL PLAINS.  
 
AS THE WILDFIRES CONTINUE TO BURN ACROSS CALIFORNIA, HIGH PRESSURE  
AND UPPER-LEVEL RIDGING SITS OVER THE WESTERN U.S. LEADING TO AIR  
STAGNATION AND AIR QUALITY ALERTS OVER THE REGION THAT WILL  
PERSIST THROUGH MONDAY. THESE ALERTS ARE IN EFFECT FOR AREAS  
ACROSS THE PACIFIC NORTHWEST AND CENTRAL/SOUTHERN CALIFORNIA.  
 
ZIEGENFELDER  
 
GRAPHICS AVAILABLE AT  
WWW.WPC.NCEP.NOAA.GOV/BASICWX/BASICWX_NDFD.PHP  

 
 
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