656  
FNUS21 KWNS 030637  
FWDDY1  
 
DAY 1 FIRE WEATHER OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK  
1236 AM CST SUN DEC 03 2017  
 
VALID 031200Z - 041200Z  
   
..SYNOPSIS
 
 
AN UPPER TROUGH WILL MOVE EASTWARD ACROSS THE WESTERN STATES TO THE  
ROCKIES/HIGH PLAINS BY LATE TONIGHT. ENHANCED MID-LEVEL WINDS  
ASSOCIATED WITH THIS TROUGH WILL OVERSPREAD PARTS OF THE  
CENTRAL/SOUTHERN HIGH PLAINS THIS AFTERNOON. AT THE SURFACE, A LOW  
WILL FORM AHEAD OF THE UPPER TROUGH ACROSS EASTERN WY AND VICINITY,  
WITH LEE TROUGHING EXTENDING SOUTHWARD FROM THIS LOW ACROSS MUCH OF  
THE CENTRAL/SOUTHERN HIGH PLAINS. THIS SURFACE LOW SHOULD DEVELOP  
EASTWARD ACROSS THE NORTHERN HIGH PLAINS THROUGH THE PERIOD. AN AREA  
OF SURFACE HIGH PRESSURE WILL STRENGTHEN IN A SUBSIDENT REGIME IN  
THE WAKE OF THE UPPER TROUGH ACROSS PARTS OF THE WESTERN CONUS, WITH  
THE ONSET OF A PROLONGED OFFSHORE WIND EVENT BEGINNING ACROSS  
PORTIONS OF SOUTHERN CA LATE TONIGHT AND CONTINUING INTO EARLY  
MONDAY MORNING.  
   
..PORTIONS OF SOUTHERN CA
 
 
STRONG/GUSTY SUNDOWNER WINDS WILL OCCUR ACROSS SOUTHERN SANTA  
BARBARA COUNTY IN CA THIS EVENING AS A FAVORABLE PRESSURE GRADIENT  
SUPPORTS THE INITIAL DEVELOPMENT OF OFFSHORE FLOW. SUSTAINED  
NORTHERLY WINDS OF 20-25 MPH APPEAR LIKELY, WITH HIGHER GUSTS OF  
40-50 MPH POSSIBLE IN THE MOUNTAINS/FOOTHILLS. LATEST  
HIGH-RESOLUTION GUIDANCE INDICATES RH VALUES WILL GENERALLY FALL  
INTO THE 15-20% RANGE BY LATE THIS EVENING, SUPPORTING THE  
CONTINUATION OF THE ELEVATED AREA ACROSS THIS REGION. LOCALLY  
CRITICAL CONDITIONS WILL BE POSSIBLE WHERE RH VALUES FALL BELOW 15%.  
 
ELEVATED TO LOCALLY CRITICAL FIRE WEATHER CONDITIONS WILL OCCUR  
ELSEWHERE ACROSS PARTS OF COASTAL SOUTHERN CA AS THE SURFACE HIGH  
DESCRIBED PREVIOUSLY DEVELOPS INTO THE GREAT BASIN AND THE PRESSURE  
GRADIENT STRENGTHENS ACROSS THIS REGION. LATEST GUIDANCE INDICATES A  
SUFFICIENT LAX-TPH AND LAX-DAG PRESSURE GRADIENT TO SUPPORT 15-30  
MPH SUSTAINED NORTHEASTERLY OFFSHORE WINDS ACROSS THE  
MOUNTAINS/FOOTHILLS OF VENTURA/LOS ANGELES/ORANGE COUNTIES AND  
VICINITY BEGINNING LATE TONIGHT AND CONTINUING THOUGH EARLY MONDAY  
MORNING (END OF THE DAY 1 PERIOD). STRONGER GUSTS TO 40-50 MPH  
APPEAR LIKELY IN THE HIGHER TERRAIN/PASSES. RH VALUES WILL BECOME  
LOWERED TO NEAR-CRITICAL LEVELS (15-20%) THROUGH DOWNSLOPE  
WARMING/DRYING PROCESSES OVERNIGHT, AND SUB-15% RH VALUES WILL BE  
POSSIBLE ON A BRIEF/SPOTTY BASIS ACROSS THIS REGION. THE LACK OF  
WIDESPREAD RH VALUES BELOW 15% CONTINUES TO PRECLUDE A CRITICAL AREA  
FOR DAY 1/SUNDAY, ALTHOUGH CRITICAL CONDITIONS WILL VERY LIKELY  
OCCUR IN THE DAY 2/MONDAY PERIOD.  
   
..PORTIONS OF THE CENTRAL/SOUTHERN HIGH PLAINS
 
 
STRONG/GUSTY SURFACE WINDS WILL DEVELOP ALONG THE LEE TROUGH  
MENTIONED PREVIOUSLY ACROSS PARTS OF EASTERN NM INTO THE TX/OK  
PANHANDLES, SOUTHEASTERN CO, AND SOUTHWESTERN KS THIS AFTERNOON AS  
ENHANCED SOUTHWESTERLY WINDS AT MID LEVELS BECOME DIURNALLY MIXED TO  
THE SURFACE. SUSTAINED WIND SPEEDS AROUND 20-30 MPH APPEAR LIKELY,  
WITH HIGHER GUSTS POSSIBLE. EVEN WITH LOW-LEVEL DOWNSLOPE  
TRAJECTORIES SUPPORTING SOME WARMING/DRYING OF THE BOUNDARY LAYER,  
RH VALUES ARE FORECAST TO BECOME ONLY MARGINALLY LOWERED TO AROUND  
20-25% THROUGH PEAK HEATING. LOCALLY ELEVATED FIRE WEATHER  
CONDITIONS MAY BRIEFLY DEVELOP ACROSS PORTIONS OF THIS REGION WHERE  
FUELS ARE DRY AND RH VALUES NEAR 20% FOR AN HOUR OR TWO. HOWEVER,  
THE LACK OF AN EVEN WARMER/DRIER LOW-LEVEL AIRMASS (WITH WIDESPREAD  
LOWERED RH VALUES OF 15-20%) PRECLUDES THE INTRODUCTION OF AN  
ELEVATED AREA.  
 
..GLEASON.. 12/03/2017  
   
..PLEASE SEE WWW.SPC.NOAA.GOV/FIRE FOR GRAPHIC PRODUCT
 
 

 
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab SPC Page Main Text Page