341  
FXUS01 KWBC 181959  
PMDSPD  
 
SHORT RANGE FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
359 PM EDT WED OCT 18 2017  
 
VALID 00Z THU OCT 19 2017 - 00Z SAT OCT 21 2017  
 
...HEAVY RAINFALL EXPECTED ACROSS THE PACIFIC NORTHWEST WITH SNOW  
FOR THE CASCADES AND NORTHERN ROCKIES...  
 
...SCATTERED THUNDERSTORMS FOR FLORIDA AND THE SOUTHWEST TO LOWER  
MISSISSIPPI VALLEY...  
   
..MUCH WARMER THAN AVERAGE FOR THE CENTRAL AND EASTERN STATES
 
 
A COLD FRONT IS EXPECTED TO MOVE ONSHORE INTO THE PACIFIC  
NORTHWEST THIS EVENING AS A STRENGTHENING UPPER-LEVEL TROUGH  
APPROACHES THE WEST COAST. VERY MOIST AIR ASSOCIATED WITH THIS  
TROUGH WILL LEAD TO THE POSSIBILITY OF LOCALLY HEAVY RAIN FOR THE  
PACIFIC NORTHWEST THROUGH WEDNESDAY NIGHT. THERE IS A MARGINAL  
RISK OF FLASH FLOODING IN EFFECT THERE. THE FRONT WILL CONTINUE TO  
PUSH EAST AND SOUTH OVER THE NEXT COUPLE OF DAYS INTO THE  
INTERMOUNTAIN WEST AND THE ROCKIES. ALONG AND BEHIND THE FRONT,  
SNOW IS EXPECTED FOR HIGHER ELEVATIONS OF THE CASCADES ON  
THURSDAY, AND SPREADING INTO THE INTERMOUNTAIN WEST AND NORTHERN  
ROCKIES BY FRIDAY MORNING.  
 
A STATIONARY FRONT WILL LINGER NEAR SOUTHERN FLORIDA FOR THE NEXT  
FEW DAYS. THIS FRONT AND PLENTY OF MOISTURE WILL LEAD TO SCATTERED  
SHOWERS AND THUNDERSTORMS ACROSS MAINLY EASTERN AND SOUTHERN  
FLORIDA. ADDITIONALLY, SCATTERED THUNDERSTORMS ARE POSSIBLE FOR  
THE SOUTHWEST AS A WEAK UPPER-LEVEL TROUGH APPROACHES. THESE  
THUNDERSTORMS WILL SPREAD INTO THE SOUTHERN PLAINS BY THURSDAY AND  
INTO THE LOWER MISSISSIPPI VALLEY BY FRIDAY AS THE TROUGH MOVES  
EASTWARD.  
 
IN THE CENTRAL U.S., WARMTH WILL PREVAIL THROUGH THE END OF THE  
WORKWEEK AS A WARM FRONT LIFTS NORTH INTO CANADA ON THURSDAY. THE  
NORTHERN PLAINS IN PARTICULAR IS FORECAST TO BE UP TO 25 DEGREES  
ABOVE AVERAGE ON THURSDAY AND FRIDAY. THIS PLUS THE DRY CONDITIONS  
WILL LEAD TO AN ELEVATED FIRE RISK THERE. THE EASTERN U.S. WILL BE  
WARMER THAN AVERAGE AS WELL, SINCE HIGH PRESSURE CENTERED OVER THE  
SOUTHERN APPALACHIANS WILL DOMINATE. WITH THE COLD FRONT MAKING  
ITS WAY THROUGH THE WESTERN STATES, HIGH TEMPERATURES 10-15  
DEGREES BELOW AVERAGE ARE EXPECTED FOR THE PACIFIC COAST ON  
THURSDAY AND FRIDAY AND INTO THE INTERMOUNTAIN WEST BY FRIDAY.  
 
TATE  
 
GRAPHICS AVAILABLE AT  
WWW.WPC.NCEP.NOAA.GOV/BASICWX/BASICWX_NDFD.PHP  

 
 
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