065  
FNUS22 KWNS 040756  
FWDDY2  
 
DAY 2 FIRE WEATHER OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK  
0155 AM CST MON DEC 04 2017  
 
VALID 051200Z - 061200Z  
 
...EXTREMELY CRITICAL FIRE WEATHER AREA FOR PORTIONS OF  
VENTURA...LOS ANGELES...ORANGE...SAN BERNARDINO...AND RIVERSIDE  
COUNTIES IN SOUTHERN CALIFORNIA...   
..CRITICAL FIRE WEATHER AREA FOR PORTIONS OF SOUTHERN CALIFORNIA
 
 
   
..SYNOPSIS
 
 
A LARGE-SCALE UPPER TROUGH OVER THE CENTRAL/EASTERN CONUS AND  
ONTARIO WILL MAKE ONLY SLOW EASTWARD PROGRESS ON DAY 2/TUESDAY.  
MEANWHILE, UPPER RIDGING OVER THE EASTERN PACIFIC WILL BECOME  
PROMINENT ACROSS PARTS OF THE WESTERN CONUS BY TUESDAY NIGHT. AT THE  
SURFACE, A BROAD AREA OF STRONG HIGH PRESSURE WILL REMAIN ACROSS THE  
NORTHERN ROCKIES AND GREAT BASIN, SUPPORTING A STRONG OFFSHORE SANTA  
ANA WIND EVENT ACROSS PARTS OF SOUTHERN CA.  
   
..PORTIONS OF SOUTHERN CA
 
 
AN EXTREMELY CRITICAL AREA HAS BEEN INCLUDED FOR PARTS OF VENTURA,  
LOS ANGELES, ORANGE, SAN BERNARDINO, AND RIVERSIDE COUNTIES IN  
SOUTHERN CA FOR DAY 2/TUESDAY. THIS IS A CONTINUATION AND EXPANSION  
OF THE EXTREMELY CRITICAL AREA VALID FOR DAY 1/MONDAY. ACROSS THESE  
AREAS, SUSTAINED WINDS OF 30-40 MPH WILL VERY LIKELY CONTINUE  
THROUGH AT LEAST TUESDAY EVENING WHILE THE SURFACE PRESSURE GRADIENT  
IS MAXIMIZED. STRONGER GUSTS OF 60-80 MPH MAY OCCUR IN THE HIGHER  
TERRAIN OF THESE COUNTIES GIVEN ENHANCED NORTHEASTERLY LOW-LEVEL  
FLOW THAT WILL REMAIN PRESENT. THESE VERY STRONG DOWNSLOPE WINDS  
WILL ACT TO WARM/DRY THE LOW LEVELS, AND RH VALUES WILL LIKELY  
REMAIN IN THE 5-10% RANGE FOR MUCH OF DAY 2/TUESDAY. FUELS WILL ALSO  
BE VERY DRY AND RECEPTIVE TO LARGE FIRE STARTS AND EXTREME FIRE  
SPREAD GIVEN THE EXPECTED METEOROLOGICAL CONDITIONS.  
 
OF NOTE, DOWNTOWN LOS ANGELES AND MUCH OF THE LA BASIN HAVE BEEN  
SPECIFICALLY EXCLUDED FROM THE EXTREMELY CRITICAL AREA FOR DAY  
2/TUESDAY, AS SUSTAINED WINDS WILL LIKELY REMAIN SOMEWHAT LESS  
(GENERALLY IN THE 20-30 MPH RANGE) PER CONSENSUS OF LATEST  
HIGH-RESOLUTION GUIDANCE). REGARDLESS, CRITICAL CONDITIONS ARE STILL  
EXPECTED FOR THIS MAJOR METRO AREA AND VICINITY.  
 
CRITICAL FIRE WEATHER CONDITIONS WILL OCCUR ACROSS A LARGER PORTION  
OF SOUTHERN CA SURROUNDING THE EXTREMELY CRITICAL AREA. HERE,  
SUSTAINED WINDS OF 20-30 MPH WILL BE COMMON, WITH GUSTS OF 45-60 MPH  
LIKELY IN THE MOUNTAINS/FOOTHILLS. RH VALUES OF 5-15% WILL ALSO  
OCCUR THROUGH THE PERIOD DUE TO CONTINUED DOWNSLOPE WARMING/DRYING  
OF AN ALREADY DRY AIRMASS. RH RECOVERY LATE TUESDAY INTO WEDNESDAY  
MORNING WILL LIKELY BE VERY POOR AS WINDS WILL REMAIN STRONG/GUSTY  
ACROSS MUCH OF SOUTHERN CA. CONSENSUS OF LATEST GUIDANCE INDICATES  
THE PRESSURE GRADIENT ACROSS THIS REGION MAY WEAKEN SOMEWHAT FROM  
TUESDAY NIGHT INTO EARLY WEDNESDAY MORNING, AND WIND SPEEDS/GUSTS  
MAY LESSEN SLIGHTLY AS A RESULT. HOWEVER, CRITICAL FIRE WEATHER  
CONDITIONS WILL LIKELY CONTINUE ACROSS BOTH THE CRITICAL AND  
EXTREMELY CRITICAL DESIGNATIONS THROUGH EARLY WEDNESDAY MORNING (END  
OF THE DAY 2/TUESDAY PERIOD INTO DAY 3/WEDNESDAY).  
 
..GLEASON.. 12/04/2017  
   
..PLEASE SEE WWW.SPC.NOAA.GOV/FIRE FOR GRAPHIC PRODUCT
 
 

 
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab SPC Page Main Text Page