146  
FNUS22 KWNS 031939  
FWDDY2  
 
DAY 2 FIRE WEATHER OUTLOOK CORR 1  
NWS STORM PREDICTION CENTER NORMAN OK  
0138 PM CST SUN DEC 03 2017  
 
VALID 041200Z - 051200Z  
 
CORRECTED FOR GRAPHIC LABEL  
 
...EXTREMELY CRITICAL FIRE WEATHER AREA FOR THE SANTA MONICA  
MOUNTAINS VICINITY OF SOUTHERN CALIFORNIA...   
..CRITICAL FIRE WEATHER AREA FOR PORTIONS OF SOUTHERN CALIFORNIA
 
 
   
..PORTIONS OF SOUTHERN CALIFORNIA
 
 
LATEST HIGH RESOLUTION GUIDANCE FROM THE ESRL-HRRR SHOWS RH VALUES  
WILL FALL INTO THE UPPER SINGLE DIGITS TO NEAR 10 PERCENT ACROSS  
PORTIONS OF SOUTHERN CA BY MONDAY AFTERNOON. CONFIDENCE HAS  
INCREASED THAT THESE VERY LOW RH VALUES WILL MATERIALIZE DURING PEAK  
HEATING AND COINCIDE WITH VERY STRONG WINDS AROUND THE SANTA MONICA  
MOUNTAINS VICINITY. AS SUCH, AN UPGRADE TO EXTREMELY CRITICAL HAS  
BEEN INTRODUCED THIS UPDATE. THE ELEVATED FIRE WEATHER AREA HAS ALSO  
BEEN EXTENDED NORTH AND WEST ACROSS MORE OF SANTA BARBARA COUNTY.  
OTHERWISE, THE ONGOING FORECAST REMAINS SIMILAR TO THE PREVIOUS  
OUTLOOK AND FURTHER DETAILS CAN BE FOUND IN THE DISCUSSION BELOW.  
   
..PORTIONS OF THE CENTRAL/SOUTHERN PLAINS
 
 
NO CHANGES NEEDED. SEE PREVIOUS DISCUSSION BELOW FOR MORE DETAILS.  
 
..LEITMAN.. 12/03/2017  
   
PREV DISCUSSION
 
/ISSUED 0132 AM CST SUN DEC 03 2017/  
   
..SYNOPSIS
 
 
THE PRIMARY UPPER TROUGH SHOULD MOVE EAST-NORTHEASTWARD ACROSS THE  
NORTHERN PLAINS INTO THE UPPER MIDWEST/GREAT LAKES REGION ON DAY  
2/MONDAY. A POSITIVELY TILTED TRAILING PORTION OF THIS UPPER TROUGH  
WILL LIKELY REMAIN OVER PORTIONS OF THE GREAT BASIN AND SOUTHWEST  
THROUGH THE PERIOD. AT THE SURFACE, A COLD FRONT WILL SWEEP  
SOUTHEASTWARD ACROSS MUCH OF THE CENTRAL/SOUTHERN PLAINS AS A LOW  
DEVELOPS NORTHEASTWARD ACROSS THE UPPER MIDWEST. LARGE-SCALE  
SUBSIDENCE IN THE WAKE OF THE UPPER TROUGH WILL SUPPORT A BROAD AND  
STRONG SURFACE HIGH ACROSS THE NORTHERN ROCKIES AND GREAT BASIN. THE  
SURFACE PRESSURE GRADIENT ACROSS SOUTHERN CA WILL STRENGTHEN MONDAY  
EVENING INTO EARLY TUESDAY MORNING, AND HIGH-END CRITICAL FIRE  
WEATHER CONDITIONS ARE EXPECTED ACROSS PARTS OF THIS REGION IN THE  
SECOND HALF OF THE DAY 2/MONDAY PERIOD.  
   
..PORTIONS OF SOUTHERN CA
 
 
CRITICAL FIRE WEATHER CONDITIONS WILL LIKELY DEVELOP SHORTLY AFTER  
12Z MONDAY MORNING AS DIURNAL HEATING AND CONTINUED DOWNSLOPE  
WARMING/DRYING ACT ON AN ALREADY DRY AIRMASS ACROSS VENTURA/LOS  
ANGELES/ORANGE COUNTIES AND SURROUNDING AREAS. RH VALUES WILL  
RAPIDLY PLUMMET BELOW 15% THROUGH EARLY MONDAY AFTERNOON, AND THEY  
WILL LIKELY FALL INTO THE 5-10% RANGE BY LATE MONDAY EVENING.  
OVERNIGHT RH RECOVERY INTO EARLY TUESDAY MORNING IS EXPECTED TO BE  
VERY POOR. GIVEN THE FORECAST STRENGTH OF THE SURFACE PRESSURE  
GRADIENT, SUSTAINED NORTHEASTERLY WINDS ACROSS THIS REGION WILL BE  
AT LEAST IN THE 20-35 MPH RANGE, WITH HIGHER GUSTS OF 50-65 MPH  
LIKELY IN THE MOUNTAINS/FOOTHILLS. SOME GUSTS TO 80 MPH ARE NOT OUT  
OF THE QUESTION IN THE HIGHEST TERRAIN GIVEN THE ENHANCED LOW-LEVEL  
NORTHEASTERLY WINDS THAT WILL BE PRESENT.  
 
THE SURFACE PRESSURE GRADIENT WILL LIKELY BE STRONGEST ACROSS  
SOUTHERN CA LATE MONDAY NIGHT INTO TUESDAY MORNING (THROUGH END OF  
THE DAY 2/MONDAY PERIOD AND CONTINUING INTO DAY 3/TUESDAY). LATEST  
HIGH-RESOLUTION GUIDANCE SUGGESTS HIGH-END CRITICAL CONDITIONS MAY  
DEVELOP IN THIS TIME FRAME ACROSS PARTS OF VENTURA, LOS ANGELES, AND  
ORANGE COUNTIES, WITH SUSTAINED WINDS IN EXCESS OF 30 MPH AND RH  
VALUES BELOW 10% OCCURRING IN COMBINATION WITH VERY DRY AND  
RECEPTIVE FUELS. A SMALL EXTREMELY CRITICAL AREA MAY BE NEEDED  
ACROSS THIS REGION PENDING ADDITIONAL CONFIRMING MODEL GUIDANCE.  
 
FOR LOCATIONS FARTHER SOUTH, CRITICAL CONDITIONS MAY BE DELAYED  
UNTIL MONDAY EVENING, BUT SUSTAINED NORTHEASTERLY TO EASTERLY WINDS  
OF 20-30 MPH ARE STILL EXPECTED TO OVERLAP CRITICALLY LOWERED RH  
VALUES IN THE 10-15% RANGE AND DRY FUELS THROUGH THE LATTER HALF OF  
THE DAY 2/MONDAY PERIOD. THESE FORECAST CONDITIONS SUPPORT A  
CRITICAL DELINEATION ACROSS WESTERN PORTIONS OF SAN BERNARDINO AND  
RIVERSIDE COUNTIES, AS WELL AS MUCH OF SAN DIEGO COUNTY.  
   
..PORTIONS OF THE CENTRAL/SOUTHERN PLAINS
 
 
IN THE WAKE OF THE COLD FRONT MENTIONED ABOVE, STRONG/GUSTY  
NORTHWESTERLY WINDS OF 20-30 MPH WILL LIKELY OCCUR ACROSS MUCH OF KS  
INTO OK AND THE TX/OK PANHANDLES MONDAY AFTERNOON AND EARLY EVENING.  
HIGHER GUSTS UP TO 40 MPH WILL BE POSSIBLE GIVEN THE STRENGTH OF THE  
MID-LEVEL FLOW THAT SHOULD BE DIURNALLY MIXED TO THE SURFACE. WITH A  
DRY AIRMASS ALREADY IN PLACE ACROSS PARTS OF THESE REGIONS, RH  
VALUES WILL LIKELY BECOME LOWERED INTO THE 15-25% RANGE FOR AT LEAST  
A FEW HOURS BEHIND THE COLD FRONT PASSAGE.  
 
SOME LOCALLY CRITICAL CONDITIONS MAY BRIEFLY OCCUR ACROSS PORTIONS  
OF SOUTHERN/CENTRAL KS INTO WESTERN OK AND THE TX/OK PANHANDLES  
IMMEDIATELY BEHIND THE FRONT, WHERE RH VALUES MAY BECOME CRITICALLY  
REDUCED. STILL, LATEST GUIDANCE SUGGESTS THIS MAY OCCUR FOR JUST AN  
HOUR OR TWO, SO HAVE NOT INCLUDED A CRITICAL AREA AT THIS TIME.  
REGARDLESS, WIDESPREAD ELEVATED CONDITIONS ARE ANTICIPATED ACROSS  
PARTS OF THE CENTRAL/SOUTHERN PLAINS WHERE GENERALLY DRY/DORMANT  
FUELS SHOULD SUPPORT LARGE FIRE SPREAD GIVEN THE FORECAST  
METEOROLOGICAL CONDITIONS.  
   
..PLEASE SEE WWW.SPC.NOAA.GOV/FIRE FOR GRAPHIC PRODUCT
 
 

 
 
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