977  
FNUS22 KWNS 051750  
FWDDY2  
 
DAY 2 FIRE WEATHER OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK  
1149 AM CST TUE DEC 05 2017  
 
VALID 061200Z - 071200Z  
   
..CRITICAL FIRE WEATHER AREA FOR PORTIONS OF SOUTHERN CA
 
 
   
..PORTIONS OF SOUTHERN CA
 
 
HIGH-END CRITICAL FIRE WEATHER CONDITIONS WILL CONTINUE ON DAY  
2/WEDNESDAY. ONLY MINOR ADJUSTMENTS HAVE BEEN MADE TO THE CRITICAL  
AND ELEVATED AREAS, BUT FORECAST PHILOSOPHY REMAINS UNCHANGED.  
 
WHILE THERE MAY BE A SLIGHT DECREASE IN WIND SPEEDS THROUGH  
WEDNESDAY AFTERNOON, GUIDANCE CONTINUES TO INDICATE THAT THE SURFACE  
PRESSURE GRADIENT WILL RE-INTENSIFY LATE WEDNESDAY NIGHT INTO DAY  
3/THURSDAY. AS A RESULT, EXPECT WIND SPEEDS TO INCREASE TOWARD THE  
END OF THE FORECAST PERIOD. CONDITIONS COULD BECOME SIMILAR TO THOSE  
SEEN EARLY TUESDAY MORNING AND AN UPGRADE TO EXTREMELY CRITICAL  
COULD BECOME NECESSARY IN HIGHER ELEVATIONS. HOWEVER, CONFIDENCE IS  
TOO LOW IN EXTREMELY CRITICAL CONDITIONS DEVELOPING BEFORE THE END  
OF THE FORECAST PERIOD, PRECLUDING AN UPGRADE AT THIS TIME.  
REGARDLESS, DANGEROUS AND VOLATILE FIRE WEATHER CONDITIONS WILL  
PERSIST ACROSS THE REGION ON DAY 2/WEDNESDAY.  
 
..LEITMAN.. 12/05/2017  
   
PREV DISCUSSION
 
/ISSUED 0135 AM CST TUE DEC 05 2017/  
   
..SYNOPSIS
 
 
A HIGHLY AMPLIFIED UPPER PATTERN WILL REMAIN ACROSS THE CONUS ON DAY  
2/WEDNESDAY AS A LARGE-SCALE UPPER TROUGH/LOW ENCOMPASSES THE  
CENTRAL/EASTERN CONUS. AN UPPER RIDGE WILL BE CENTERED OVER THE  
EASTERN PACIFIC AND WESTERN CONUS. AT THE SURFACE, A STRONG AND  
BROAD AREA OF HIGH PRESSURE WILL REMAIN ACROSS THE NORTHERN ROCKIES  
AND GREAT BASIN THROUGH THE PERIOD. GENERALLY COOL POST-FRONTAL  
CONDITIONS WILL TEMPER FIRE WEATHER CONCERNS EAST OF THE ROCKIES.  
CRITICAL FIRE WEATHER CONDITIONS WILL CONTINUE ACROSS PARTS OF  
SOUTHERN CA AS MODERATE TO STRONG SANTA ANA WINDS OCCUR.  
   
..PORTIONS OF SOUTHERN CA
 
 
A PROLONGED OFFSHORE WIND EVENT WILL CONTINUE ACROSS PARTS OF  
SOUTHERN CA ON DAY 2/WEDNESDAY AS THE SURFACE PRESSURE GRADIENT  
REMAINS STRONG ENOUGH TO SUPPORT 20-30 MPH NORTHEASTERLY/EASTERLY  
SUSTAINED WINDS. GUSTS OF 40-50 MPH WILL BE POSSIBLE ACROSS THE  
MOUNTAINS/FOOTHILLS OF COASTAL SOUTHERN CA. RH VALUES WILL REMAIN  
CRITICALLY LOWERED IN THE 5-15% RANGE OWING TO BOTH LOW-LEVEL  
DOWNSLOPE WARMING/DRYING AND DIURNAL HEATING. LATEST DETERMINISTIC  
AND ENSEMBLE GUIDANCE INDICATES THAT THE SURFACE PRESSURE GRADIENT  
WILL BE SOMEWHAT WEAKER THROUGH AT LEAST THE FIRST HALF OF THE DAY  
2/WEDNESDAY PERIOD COMPARED TO DAY 1/TUESDAY. HAVE THEREFORE NOT  
INCLUDED AN EXTREMELY CRITICAL AREA FOR ANY PORTION OF SOUTHERN CA  
AT THIS TIME. STILL, HIGH-END CRITICAL CONDITIONS WILL REMAIN LIKELY  
IN FAVORED HIGH TERRAIN, AND WITH VERY DRY FUELS IN PLACE, LARGE  
FIRE SPREAD WILL LIKELY OCCUR WITH ANY NEW/ONGOING FIRES.  
 
THERE ARE SOME INDICATIONS THAT THE SURFACE PRESSURE GRADIENT WILL  
RESTRENGTHEN SLIGHTLY LATE WEDNESDAY NIGHT INTO EARLY THURSDAY  
MORNING, AND A CORRESPONDING INCREASE IN WIND SPEEDS/GUSTY MAY OCCUR  
IN THIS TIME FRAME. HOWEVER, CONFIDENCE IN EXTREMELY CRITICAL  
CONDITIONS (SUSTAINED 30+ MPH WINDS WITH SUB-10% RH VALUES) REMAINS  
TOO LOW TO INTRODUCE AN EXTREMELY CRITICAL AREA.  
   
..PLEASE SEE WWW.SPC.NOAA.GOV/FIRE FOR GRAPHIC PRODUCT
 
 

 
 
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