335  
FNUS21 KWNS 041519  
FWDDY1  
 
DAY 1 FIRE WEATHER OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK  
1018 AM CDT THU SEP 04 2025  
 
VALID 041700Z - 051200Z  
 
THE ISODRYT AREA WAS EXPANDED IN PORTIONS OF NORTHERN CALIFORNIA,  
OREGON, AND INTO THE WASHINGTON CASCADES BASED ON THE LATEST  
HIGH-RESOLUTION FORECAST GUIDANCE. ADDITIONALLY, DEEP PYROCONVECTION  
WAS OBSERVED ON FOUR DIFFERENT FIRES IN THE NORTHWEST YESTERDAY,  
INCLUDING LIGHTNING FROM IT ON THE WILDCAT AND LOWER SUGARLOAF FIRES  
IN WASHINGTON. DEEP PYROCONVECTION REMAINS POSSIBLE ON ACTIVE LARGE  
WILDFIRES ACROSS THE NORTHWEST AND INTO NORTH IDAHO AND NORTHWEST  
CALIFORNIA TODAY, ALTHOUGH SMOKE AND CLOUD COVER MAY HELP MITIGATE.  
ISOLATED HIGH-BASED THUNDERSTORMS ARE POSSIBLE OVERNIGHT IN PORTIONS  
OF WESTERN/CENTRAL OREGON.  
 
AS A COLD FRONT PUSHES SOUTH INTO THE NORTHERN ROCKIES,  
NORTHEAST-EASTERLY WINDS WILL INCREASE ACROSS WESTERN MONTANA, NORTH  
IDAHO, AND EASTERN WASHINGTON THIS EVENING AND OVERNIGHT. GUSTY  
WINDS OF 20-35 MPH ARE LIKELY BUT RH IS FORECAST TO BE 30-50%. GIVEN  
THE AMOUNT OF FIRE ACTIVITY, GUSTY WINDS, AND WIND SHIFT, THERE IS  
CONCERN FOR INCREASED ACTIVITY FROM LOCALLY ELEVATED CONDITIONS.  
 
LOCALLY ELEVATED CONDITIONS ARE ALSO POSSIBLE ACROSS PORTIONS OF NEW  
ENGLAND TODAY IN A PRE-FRONTAL ENVIRONMENT. SOUTHERLY WINDS OF 10-20  
MPH AMID MINIMUM RH OF 35-50% ARE FORECAST THIS AFTERNOON, AND FUELS  
ARE CURRENTLY VERY DRY IN PORTIONS OF NEW ENGLAND. HOWEVER, SHOWERS  
AND THUNDERSTORMS WITH INCREASING RH WILL ARRIVE THIS EVENING AND  
OVERNIGHT FOR MUCH OF NEW ENGLAND.  
 
..NAUSLAR.. 09/04/2025  
   
PREV DISCUSSION
 
/ISSUED 1247 AM CDT THU SEP 04 2025/  
   
..SYNOPSIS
 
 
A DEPARTING MID-LEVEL WAVE WILL AID IN THUNDERSTORM DEVELOPMENT  
ACROSS PORTIONS OF NORTHERN CALIFORNIA INTO WASHINGTON THIS  
AFTERNOON. STORM MOTIONS TODAY WILL BE SLOWER THAN IN RECENT DAYS. A  
MIX OF WET/DRY THUNDERSTORMS IS EXPECTED. HOWEVER, MAINLY MID-LEVEL  
MOISTURE AND DRY SUB-CLOUD LAYER SHOULD REDUCE RAINFALL AMOUNTS AND  
INCREASE POTENTIAL FOR DRY LIGHTNING STRIKES TO OCCUR. ACTIVITY OVER  
THE LAST 24-48 HOURS HAS GENERALLY PRODUCED 0.25" OF RAIN WITH  
SEVERAL NEW FIRES DETECTED. AN AREA OF ISOLATED DRY THUNDERSTORM  
RISK WAS MAINTAINED ACROSS PORTIONS OF NORTHERN CALIFORNIA INTO  
CENTRAL OREGON WITH THIS OUTLOOK. A STRIKE OR TWO MAY EXTEND AS FAR  
NORTH AS THE WASHINGTON CASCADES.  
   
..PLEASE SEE WWW.SPC.NOAA.GOV/FIRE FOR GRAPHIC PRODUCT
 
 

 
 
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