608  
FXUS01 KWBC 111934  
PMDSPD  
 
SHORT RANGE FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
333 PM EDT WED OCT 11 2017  
 
VALID 00Z THU OCT 12 2017 - 00Z SAT OCT 14 2017  
 
...ELEVATED TO CRITICAL WILDFIRE DANGER ACROSS THE STATE OF  
CALIFORNIA...  
 
...MODERATE TO HEAVY RAIN/SNOW LIKELY ACROSS THE PACIFIC  
NORTHWEST...  
 
...WELL ABOVE NORMAL TEMPERATURES TO PREVAIL OVER THE SOUTHEASTERN  
UNITED STATES...  
 
WITH A NUMBER OF ACTIVE FIRES CURRENTLY IMPACTING CALIFORNIA,  
ATMOSPHERIC CONDITIONS REMAIN RIPE TO PRODUCE ADDITIONAL CONCERNS  
THE NEXT COUPLE OF DAYS. BASED ON THE LATEST FIRE WEATHER OUTLOOK  
FROM THE STORM PREDICTION CENTER, A COUPLE OF AREAS ARE BEING  
HIGHLIGHTED FOR EITHER AN ELEVATED OR CRITICAL RISK FOR WILDFIRE  
DANGER. THESE REGIONS INCLUDE COASTAL LOCALES JUST NORTH OF LOS  
ANGELES AS WELL AS THE SAN FRANCISCO BAY AREA INTO THE CENTRAL  
VALLEY. IN THE WAKE OF A FRONTAL PASSAGE ACROSS THE INTERMOUNTAIN  
WEST, A BUILDING SURFACE RIDGE WILL ENSURE THE PERSISTENCE OF  
OFFSHORE FLOW. THIS WILL USHER IN DRY, GUSTY WINDS THROUGH THE  
MOUNTAIN PASSES WHICH WILL EFFECTIVELY LOWER THE RELATIVE HUMIDITY  
VALUES ACROSS THE REGION. SUCH CONDITIONS WILL MAKE ANY RELIEF  
EFFORTS MORE DIFFICULT DURING THE NEXT COUPLE OF DAYS.  
 
AS AN UPPER RIDGE REMAINS IN PLACE ACROSS THE EASTERN PACIFIC, A  
CONVEYOR BELT OF SHORTWAVE TROUGHS WILL DIP DOWN FROM FAR WESTERN  
BRITISH COLUMBIA TOWARD THE PACIFIC NORTHWEST. ENERGETICS WITH  
EACH APPROACHING SYSTEM WILL ACCESS AN ABUNDANT POOL OF MOISTURE  
GIVEN PERSISTENT LOW-LEVEL ONSHORE FLOW. THE USUAL UPSLOPE  
OROGRAPHICS SHOULD PLAY A KEY ROLE IN AUGMENTING LOCAL  
PRECIPITATION AMOUNTS ACROSS THE WASHINGTON/OREGON CASCADES. THE  
LATEST FORECAST SUGGEST 2 TO 3 INCHES OF PRECIPITATION FOCUSED ON  
THESE MOUNTAIN RANGES WITH SNOW LEVELS DROPPING ENOUGH TO SUPPORT  
12 TO 18 INCHES OVER THE TALLER PEAKS. COLD ADVECTION ACCOMPANYING  
THIS SYSTEM WILL ALLOW FOR A SUFFICIENT COOL DOWN ACROSS MUCH OF  
THE NORTHWESTERN UNITED STATES. DEPARTURES FROM NORMAL WILL LIKELY  
BE IN THE 10 TO 15 DEGREE BELOW AVERAGE RANGE WHICH FAVORS HIGHS  
IN THE 30S AND 40S ACROSS THE HIGHER TERRAIN WITH 50S MORE  
COMMONPLACE OVER THE LOWER ELEVATIONS.  
 
ELSEWHERE, UNSETTLED CONDITIONS SHOULD CONTINUE ALONG THE EASTERN  
SEABOARD AS A PROGRESSIVE UPPER TROUGH SWEEPS THROUGH THE GREAT  
LAKES AND UPPER MID-ATLANTIC. A SLOW-MOVING FRONTAL ZONE WILL BE  
STUBBORN TO EXIT THE COAST WHICH SHOULD KEEP A THREAT FOR RAINFALL  
IN THE FORECAST THROUGH FRIDAY. GIVEN THE STRONGER DYNAMICS  
MIGRATE INTO THE WESTERN ATLANTIC BY THURSDAY MORNING, THE  
ACTIVITY SHOULD BE MORE SCATTERED IN NATURE, POSSIBLY FOCUSING IN  
LOCATIONS WHICH RECEIVE MORE SOLAR RADIATION. A BETTER CHANCE FOR  
HEAVY RAINFALL IS POSSIBLE OVER SOUTHERN FLORIDA AS AN EASTERLY  
WAVE SWEEPS THROUGH THE BAHAMAS AND POINTS WESTWARD. IN ADDITION  
TO THE THREAT FOR PRECIPITATION, CONDITIONS WILL BE REMAIN MILD  
AND HUMID, PARTICULARLY OVER THE SOUTHEASTERN UNITED STATES. THERE  
MAY BE A FEW DAILY RECORDS BROKEN ON THURSDAY MORNING DUE TO THE  
WARM OVERNIGHT LOWS.  
 
RUBIN-OSTER  
 
GRAPHICS AVAILABLE AT  
WWW.WPC.NCEP.NOAA.GOV/BASICWX/BASICWX_NDFD.PHP  

 
 
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