426  
FXUS01 KWBC 110649  
PMDSPD  
 
SHORT RANGE FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
148 AM EST TUE DEC 11 2018  
 
VALID 12Z TUE DEC 11 2018 - 12Z THU DEC 13 2018  
 
...HEAVY RAIN AND MOUNTAIN SNOW EXPECTED FOR THE NORTHWESTERN U.S.  
AND RELATIVELY UNEVENTFUL FOR MOST OF THE CENTRAL AND EASTERN  
STATES...  
 
AN ACTIVE WEATHER PATTERN WILL REMAIN IN PLACE ACROSS THE PACIFIC  
NORTHWEST OVER THE NEXT COUPLE OF DAYS, WITH A RELATIVELY STRONG  
PACIFIC COLD FRONT AFFECTING THE REGION ON TUESDAY. THIS WILL  
RESULT IN WIDESPREAD MODERATE TO HEAVY RAIN AND MOUNTAIN SNOWS  
INLAND ACROSS WASHINGTON AND OREGON. THIS MOISTURE IS EXPECTED TO  
SPREAD ACROSS THE NORTHERN GREAT BASIN AND NORTHERN ROCKIES BY  
TUESDAY NIGHT AND INTO WEDNESDAY MORNING. THE HIGHER ELEVATIONS  
OF THE NORTHERN CASCADES MAY SEE SNOWFALL ACCUMULATIONS UP TO TWO  
FEET, AND 6 TO 18 INCHES POSSIBLE FOR PORTIONS OF THE NORTHERN  
ROCKIES. AFTER A BRIEF LULL ACROSS THE PACIFIC NORTHWEST, ANOTHER  
FRONTAL SYSTEM WILL APPROACH LATE WEDNESDAY, BRINGING ANOTHER  
ROUND OF POTENTIALLY HEAVY RAIN AND MOUNTAIN SNOW TO THE REGION.  
 
ACROSS THE NORTH-CENTRAL PART OF THE NATION, A LOW PRESSURE SYSTEM  
WILL CROSS THE GREAT LAKES AND PORTIONS OF THE NORTHEAST THROUGH  
TUESDAY, BRINGING SCATTERED AREAS OF SNOW SHOWERS. A WEAK COLD  
FRONT IS EXPECTED TO CROSS THE CENTRAL AND NORTHERN PLAINS ON  
TUESDAY, WITH SOME SCATTERED AND RELATIVELY LIGHT PRECIPITATION  
POSSIBLE INTO WEDNESDAY ACROSS PORTIONS OF THE NORTHERN PLAINS AND  
THE MIDWEST STATES. A NEW SURFACE LOW DEVELOPS ACROSS THE WESTERN  
HIGH PLAINS WEDNESDAY NIGHT AND THIS WILL BEGIN ADVECTING GULF OF  
MEXICO MOISTURE NORTHWARD BY THURSDAY MORNING ACROSS THE SOUTHERN  
PLAINS, WITH SHOWERS AND SOME THUNDERSTORMS DEVELOPING.  
 
THE CONTIGUOUS U.S. WILL BE LARGELY CUT OFF FROM ANY SIGNIFICANT  
INCURSIONS OF ARCTIC AIR MASSES DURING THE SHORT RANGE FORECAST  
PERIOD, AND HIGH TEMPERATURES THROUGH THE MIDDLE OF THE WEEK ARE  
EXPECTED TO RANGE FROM 5 TO 15 DEGREES ABOVE AVERAGE ACROSS MUCH  
OF THE CENTRAL U.S. THE EAST COAST SHOULD REMAIN SEASONABLY COOL  
WITH TEMPERATURES UP TO 10 DEGREES BELOW AVERAGE, ALTHOUGH  
TEMPERATURES WILL SLOWLY MODERATE SOME BY WEDNESDAY.  
 
D. HAMRICK  
 
GRAPHICS AVAILABLE AT  
WWW.WPC.NCEP.NOAA.GOV/BASICWX/BASICWX_NDFD.PHP  

 
 
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