705  
FNUS21 KWNS 231524  
FWDDY1  
 
DAY 1 FIRE WEATHER OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK  
1024 AM CDT SAT JUN 23 2018  
 
VALID 231700Z - 241200Z  
 
...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF THE SOUTHERN GREAT  
BASIN INTO NORTHERN ARIZONA...  
 
CRITICAL FIRE WEATHER CONDITIONS ARE EXPECTED TO DEVELOP ACROSS  
PORTIONS OF THE SOUTHERN GREAT BASIN AND INTO NORTHERN ARIZONA THIS  
AFTERNOON/EVENING. LOCALLY CRITICAL FIRE WEATHER CONDITIONS  
(SUSTAINED SURFACE WINDS OF 10-20 MPH; RH VALUES OF 5-20%) SHOULD  
DEVELOP ACROSS PORTIONS OF EASTERN UTAH AND INTO WESTERN/SOUTHERN  
COLORADO THIS AFTERNOON INTO THE EVENING ALONG/AHEAD OF AN  
APPROACHING MID-LEVEL JET. THE ELEVATED AREA WAS EXPANDED FARTHER  
INTO COLORADO TO REFLECT THIS.  
 
VERY HOT/DRY/UNSTABLE CONDITIONS (SURFACE TEMPERATURES 100+ F AND  
SINGLE DIGIT RH) ARE EXPECTED TO DEVELOP IN THE SACRAMENTO VALLEY,  
WHICH SHOULD LOCALLY ENHANCE THE THERMAL TROUGH AND SURFACE WINDS.  
FARTHER SOUTH IN THE CENTRAL TRANSVERSE RANGES AND VICINITY, WINDS  
WILL INCREASE AS THE PRESSURE GRADIENT ENHANCES BETWEEN ONSHORE FLOW  
AND HOT/DRY INTERIOR VALLEYS. THIS WILL LEAD TO LOCALLY CRITICAL  
FIRE WEATHER CONDITIONS (SUSTAINED SURFACE WINDS 10-20 MPH; RH  
VALUES OF 5-20%) INCLUDING WIND GUSTS AROUND 40 MPH.  
 
..NAUSLAR.. 06/23/2018  
   
PREV DISCUSSION
 
/ISSUED 0147 AM CDT SAT JUN 23 2018/  
   
..SYNOPSIS
 
 
AN UPPER-LEVEL TROUGH WILL DIG INTO THE SOUTHERN/EASTERN GREAT BASIN  
TODAY. ENHANCED MID-LEVEL FLOW WILL EXIST ACROSS PARTS OF WESTERN  
NEVADA, UTAH, AND NORTHERN ARIZONA. AT THE SURFACE, A TROUGH WILL BE  
DRAPED FROM WESTERN COLORADO INTO SOUTHERN CALIFORNIA.  
   
..GREAT BASIN AND SOUTHWEST CONUS
 
 
CRITICAL FIRE WEATHER CONDITIONS ARE EXPECTED FOR PARTS OF THE  
SOUTHERN GREAT BASIN AND NORTHERN ARIZONA. STRONG SURFACE HEATING  
WILL HELP TO MIX DOWN ENHANCED MID-LEVEL FLOW FROM A PASSING  
UPPER-LEVEL TROUGH. A WEAK SURFACE TROUGH IN THE REGION WILL ALSO  
AID IN INCREASING SURFACE WINDS. ACROSS THIS AREA SURFACE WINDS OF  
25 MPH WILL BE COMMON AMIDST 5-15% RH. MINOR CHANGES HAVE BEEN MADE  
TO THE CRITICAL AREA FROM THE PREVIOUS FORECAST TO ACCOUNT FOR SMALL  
SHIFTS IN WHERE STRONG SURFACE FLOW WILL EXIST. SOME AREAS OF  
EASTERN UTAH MAY EXPERIENCE LOCALLY CRITICAL FIRE WEATHER  
CONDITIONS, BUT WINDS WILL ONLY INTERMITTENTLY REACH 25 MPH.  
 
SURROUNDING THE CRITICAL AREA, A BROAD AREA OF ELEVATED FIRE WEATHER  
CONDITIONS WILL EXIST. RH VALUES OF 5-15% WILL BE COMMON ACROSS  
THESE AREAS, BUT SURFACE WINDS WILL NOT LIKELY REACH CRITICAL LEVELS  
AS THESE AREAS WILL BE DISPLACED FROM THE STRONGEST MID-LEVEL FLOW.  
   
..PORTION OF THE SACRAMENTO VALLEY
 
CENTRAL TRAVERSE RANGES AND  
VICINITY...  
STRONG MID-LEVEL FLOW ALONG THE BACKSIDE OF THE UPPER-LEVEL TROUGH  
WILL LEAD TO ELEVATED TO LOCALLY CRITICAL FIRE WEATHER CONDITIONS IN  
THE PARTS OF THE SACRAMENTO VALLEY. RH WILL DROP TO 5-15% WITH  
DOWNSLOPING FLOW, BUT SURFACE WINDS WILL GENERALLY BE TO LIGHT AT  
15-20 MPH TO WARRANT CRITICAL DESIGNATION.  
 
FARTHER SOUTH, THE APPROACHING UPPER-LEVEL TROUGH WILL LEAD TO A  
DEEPENING SURFACE TROUGH OVER SOUTHERN CALIFORNIA AND SOUTHWEST  
NEVADA. THIS ENHANCED PRESSURE GRADIENT WILL LEAD TO ELEVATED TO  
LOCALLY CRITICAL FIRE WEATHER CONDITIONS IN THE CENTRAL TRAVERSE  
RANGES AND ADJACENT NORTHERN/EASTERN VALLEYS. RH OF 5-10% WILL BE  
PRESENT WITH SURFACE WINDS REACHING 20-25 MPH. RECENT GUIDANCE  
SUGGESTS THAT LOCALLY CRITICAL AREAS WITHIN THIS REGION ARE LIKELY;  
HOWEVER, WINDS OF 20+ MPH WILL NOT GENERALLY PERSIST FOR LONG ENOUGH  
PERIODS TO WARRANT AN ADDED CRITICAL REGION.  
   
..PLEASE SEE WWW.SPC.NOAA.GOV/FIRE FOR GRAPHIC PRODUCT
 
 

 
 
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