878  
FXUS01 KWBC 210712  
PMDSPD  
 
SHORT RANGE FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
211 AM EST TUE NOV 21 2017  
 
VALID 12Z TUE NOV 21 2017 - 12Z THU NOV 23 2017  
 
...MORE HEAVY RAIN EXPECTED FOR THE NORTHWEST AND ANOTHER COLD  
FRONT WILL SWEEP THROUGH THE CENTRAL AND EASTERN STATES...  
 
THE WEST COAST NORTH OF SAN FRANCISCO WILL BE QUITE ACTIVE  
WEATHERWISE THROUGH THE MIDDLE OF THE WEEK WITH PERSISTENT ONSHORE  
FLOW AND DEEP MOISTURE MOVING INLAND. THE RESULT OF THIS  
ATMOSPHERIC RIVER WILL BE A HEAVY RAINFALL EVENT ALONG AND WEST OF  
THE CASCADES, WITH THE POTENTIAL FOR AMOUNTS IN EXCESS OF FOUR  
INCHES POSSIBLE, PARTICULARLY FOR WESTERN WASHINGTON. MODERATE TO  
HEAVY RAIN CAN ALSO BE EXPECTED FOR PARTS OF THE NORTHERN ROCKIES.  
GIVEN THE WARM NATURE OF THIS WEATHER PATTERN AND THE RESULTING  
HIGH SNOW LEVELS, VERY LITTLE IN THE WAY OF SNOW IS EXPECTED,  
EXCEPT FOR THE HIGHEST PEAKS. SOME INSTANCES OF FLOODING WILL  
ALSO BE POSSIBLE.  
 
EAST OF THE ROCKIES, AN ARCTIC FRONT WILL QUICKLY SINK SOUTHWARD  
ACROSS THE PLAINS AND THEN REACH THE EAST COAST BY WEDNESDAY. A  
BRIEF MODERATING TREND IN TEMPERATURES IS EXPECTED ACROSS THE  
EASTERN U.S. AHEAD OF THIS BOUNDARY, MAKING FOR A PLEASANT DAY FOR  
MANY LOCATIONS ON TUESDAY. BY THE TIME THIS FRONT REACHES THE  
COAST, THE AIRMASS WILL HAVE MODIFIED AND NOT BE AS COLD AS WHAT  
THE PLAINS AND MIDWEST WILL EXPERIENCE. SHOWERS AND A FEW  
THUNDERSTORMS WILL BE POSSIBLE ACROSS FLORIDA OWING TO EASTERLY  
FLOW FROM THE ATLANTIC. WARM AND DRY CONDITIONS WILL CONTINUE FOR  
THE DESERT SOUTHWEST WITH HIGHS NEAR 90 DEGREES FOR THE LOWER  
ELEVATIONS.  
 
D. HAMRICK  
 
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