300  
FXUS01 KWBC 180758  
PMDSPD  
 
SHORT RANGE FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
257 AM EST MON DEC 18 2017  
 
VALID 12Z MON DEC 18 2017 - 12Z WED DEC 20 2017  
 
...HEAVY SNOWS LIKELY ACROSS THE CASCADES AND THE NORTHERN ROCKIES  
ON TUESDAY...  
 
...HEAVY RAINFALL AND FLASH FLOODING POSSIBLE ACROSS PORTIONS OF  
THE LOWER MISSISSIPPI VALLEY INTO THE TENNESSEE VALLEY ON  
TUESDAY...  
 
THE WORK WEEK ACROSS THE PACIFIC NORTHWEST STARTS OUT WITH SOME  
GENERAL RAIN AND MOUNTAIN SNOWS ACROSS THE HIGHER PEAKS OF THE  
WASHINGTON CASCADES AND THE NORTHERN ROCKIES ON MONDAY. BY TUESDAY  
HOWEVER, A COLD FRONT MOVING INLAND WILL BRING INCREASED MOISTURE  
TO MUCH OF THE NORTHWEST. EXPECT HEAVY RAINFALL ALONG THE  
WASHINGTON, OREGON, AND NORTHERN CALIFORNIA COASTS, WITH HEAVY  
SNOWFALL IN THE MOUNTAINS. FOR MUCH OF THE CASCADES RANGE AND THE  
NORTHERN ROCKIES, UPWARDS OF A FOOT, MAYBE 2 FEET, OF SNOW IS  
POSSIBLE.  
 
MOISTURE STREAMING NORTHWARD FROM THE GULF OF MEXICO WILL KEEP  
SHOWERS AND THUNDERSTORMS IN THE FORECAST ACROSS THE SOUTHERN  
PLAINS AND THE GULF COAST STATES THE NEXT COUPLE OF DAYS. HEAVY  
RAINFALL IS EXPECTED TO DEVELOP ACROSS PORTIONS OF THE LOWER  
MISSISSIPPI VALLEY AND INTO THE TENNESSEE VALLEY ON TUESDAY AS A  
WARM FRONT LIFTS NORTHWARD INTO THE REGION AND A SURFACE LOW  
DEVELOPS ACROSS TEXAS. THE HEAVIEST RAINFALL SHOULD FOCUS ALONG  
THE BOUNDARY FROM THE ARKLATEX REGION INTO THE TENNESSEE VALLEY  
WHERE AS MUCH AS 3 TO 4 INCHES OF RAIN MAY BE POSSIBLE ON TUESDAY  
AND INTO EARLY WEDNESDAY. WPC IS HIGHLIGHTING A SLIGHT RISK FOR  
FLASH FLOODING ACROSS THIS REGION AS WELL.  
 
ELSEWHERE, EXPECT MAINLY LIGHT RAIN OR SNOW SHOWERS ACROSS THE  
NORTHEAST TODAY AS A WARM FRONT LIFTS THROUGH. FARTHER WEST, A  
COLD FRONT MOVING ACROSS THE UPPER GREAT LAKES WILL KEEP SNOW IN  
THE FORECAST ON MONDAY, WITH MORE RAIN SPREADING INTO THE  
NORTHEAST ON TUESDAY, EVENTUALLY CHANGING OVER TO SNOW AS COLDER  
AIR FILTERS IN BEHIND THE COLD FRONT.  
 
SANTORELLI  
 
GRAPHICS AVAILABLE AT  
WWW.WPC.NCEP.NOAA.GOV/BASICWX/BASICWX_NDFD.PHP  

 
 
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