235
FNUS21 KWNS 261636
FWDDY1
DAY 1 FIRE WEATHER OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1135 AM CDT WED AUG 26 2026
VALID 261700Z - 271200Z
...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF NORTHEASTERN
CALIFORNIA...NORTHWESTERN NEVADA...AND SOUTHEASTERN OREGON...
AS AN UPPER TROUGH IMPINGES UPON THE PACIFIC NORTHWEST THIS
AFTERNOON, STRONG SOUTHWESTERLY FLOW ALOFT WILL SUPPORT AN EXPANSIVE
FIRE WEATHER THREAT ACROSS THE NORTHERN INTERMOUNTAIN WEST. A
TIGHTENING SURFACE PRESSURE GRADIENT ALONG THE CASCADES AND EMERGING
SURFACE LOW WILL COMPEL SUSTAINED SOUTHWEST WINDS OF 10-15 MPH
(GUSTS OF 20-30 MPH IN TERRAIN-FAVORED AREAS) AND RH VALUES OF
15-20% IN THE COLUMBIA BASIN AND NORTHERN SIERRA NEVADA. A REGION OF
CRITICAL CONDITIONS ARE LIKELY ACROSS NORTHEASTERN CALIFORNIA,
NORTHWESTERN NV, AND SOUTHEASTERN OREGON WHERE RH VALUES WILL
DECLINE TO LESS THAN 15% AND SUSTAINED SOUTHWEST WINDS INCREASE TO
20 MPH. NOTABLY, IN THE LAST 48 HOURS, NUMEROUS LIGHTNING STRIKES
OCCURRED WITH MINIMALLY OBSERVED PRECIPITATION (LESS THAN 0.15")
WITHIN TODAY'S CRITICAL RISK AREA AND SOUTHERN EXTENT OF THE
ELEVATED HIGHLIGHTS, INCREASING CONCERNS FOR HOLDOVERS TO EMERGE.
FUELS REMAIN RECEPTIVE ACROSS MUCH OF THE REGION, WITH ACTIVE FIRES
IN THE LANDSCAPE AND OBSERVED ERCS RANGING FROM THE 90-95TH
PERCENTILE.
12Z REFS/HREF CONTINUE TO DEPICT 50-60% PROBABILITIES OF
THUNDERSTORMS ACROSS THE NORTHERN ROCKIES THIS AFTERNOON. FORECAST
SOUNDINGS PORTRAY DEEP INVERTED-V PROFILES, MUCAPE VALES UP TO 1200
J/KG, AND LCL-EL WINDS OF 25-35 KT; AS A RESULT, ACCUMULATING
PRECIPITATION AT THE SURFACE IS EXPECTED TO BE MINIMAL, ESCALATING
THE POTENTIAL FOR LIGHTNING-INDUCED IGNITIONS WITHIN AN INCREASINGLY
RECEPTIVE FUELSCAPE. ISOLATED DRY THUNDERSTORM HIGHLIGHTS WERE
TRIMMED OUT OF FAR NORTHEASTERN WASHINGTON WHERE AFTERNOON
THUNDERSTORMS HAVE BECOME LESS PROBABLE.
FARTHER SOUTH, OFFSHORE WINDS WILL REDEVELOP THIS EVENING IN
PORTIONS OF SOUTHERN CALIFORNIA. ELEVATED FIRE WEATHER CONDITIONS
ARE EXPECTED IN FAVORED TERRAIN GAPS AND DOWNSLOPE AREAS OF
LA/VENTURA/SANTA BARBARA COUNTIES. PLEASE SEE THE PREVIOUS
DISCUSSION FOR MORE DETAILS.
..ELIZALDE-GARCIA.. 08/26/2026
PREV DISCUSSION
/ISSUED 0107 AM CDT WED AUG 26 2026/
..SYNOPSIS
AN UPPER-LEVEL TROUGH EDGING INTO THE PACIFIC NORTHWEST WILL BRING
WIDESPREAD FIRE WEATHER CONCERNS TO MUCH OF THE INTERIOR OF THE
NORTHWEST, NORTHERN GREAT BASIN AND NORTHERN ROCKIES TODAY. ISOLATED
DRY THUNDERSTORMS ARE EXPECTED ACROSS MUCH OF THE NORTHERN ROCKIES,
WHILE DRY AND BREEZY CONDITIONS DEVELOP FARTHER WEST ACROSS THE
COLUMBIA BASIN SOUTH TOWARDS THE NORTHERN GREAT BASIN AND
NORTHEASTERN CA. AN INCREASING OFFSHORE PRESSURE GRADIENT WILL BRING
AN ELEVATED FIRE WEATHER THREAT TO PARTS OF SOUTHERN CA LATE THIS
AFTERNOON INTO THE OVERNIGHT HOURS AS DRY AND BREEZY CONDITIONS
DEVELOP.
..NORTHEASTERN CALIFORNIA INTO NORTHWESTERN GREAT BASIN
A NARROW CORRIDOR OF CRITICAL FIRE WEATHER CONDITIONS IS LIKELY
TODAY ACROSS THE NORTHWESTERN FRINGE OF THE GREAT BASIN. THE
UPPER-LEVEL TROUGH AND ATTENDANT INCREASING DEEP LAYER SOUTHWEST
FLOW WILL SUPPORT SOUTHWEST SURFACE WINDS OF AROUND 20 MPH. AN
EXISTING DRY AIR MASS WITH RH FALLING TO AS LOW AS 10% AND RECEPTIVE
FUELS WILL PROMOTE WILDFIRE SPREAD, WHERE SEVERAL ACTIVE FIRES ARE
PRESENT.
...COLUMBIA BASIN SOUTHWARD TOWARDS THE NORTHERN GREAT BASIN AND
NORTHERN SIERRA NEVADA...
AN UPPER TROUGH ENCROACHING UPON THE PACIFIC NORTHWEST WILL
STRENGTHEN MID-LEVEL SOUTHWEST WINDS ACROSS MUCH OF THE NORTHWESTERN
U.S. TODAY. ALTHOUGH UPPER-LEVEL CLOUD COVER WILL INHIBIT FULL
MIXING POTENTIAL ACROSS THE REGION, THE DEEP-LAYER SOUTHWEST FLOW
AIDED BY AN EMERGING SURFACE LOW ACROSS EASTERN WA/OR WILL
CONTRIBUTE TO SOUTHWEST WINDS OF 10-15 MPH FROM NORTHEASTERN CA INTO
EASTERN OR AND THE COLUMBIA BASIN. RELATIVE HUMIDITY REDUCTIONS BY
PEAK AFTERNOON HEATING WILL LIKELY REACH AROUND 15%.
..NORTHERN ROCKIES INTO NORTHERN WASHINGTON
THE APPROACHING UPPER TROUGH WILL PROMOTE BROAD BUT DIFFUSE FORCING
FOR ASCENT AS A MID/UPPER MOISTURE PLUME PUSHES INTO THE NORTHERN
ROCKIES. AFTERNOON INSTABILITY (MLCAPE VALUES IN THE 500-1000 J/KG
RANGE), A DRY SUB-CLOUD LAYER AND NORTHEAST SHOWER/THUNDERSTORM
TRAJECTORIES OF 25-35 MPH WITH PWATS GENERALLY LESS THAN 0.8",
SHOULD LIMIT SURFACE RAINFALL THIS AFTERNOON AND EVENING AS ISOLATED
DRY THUNDERSTORMS DEVELOP ACROSS THE CENTRAL ID MOUNTAINS NORTHWARD
INTO THE ID PANHANDLE AND WESTERN MT.
..SOUTHERN CALIFORNIA
HIGH PRESSURE ALOFT WILL CONTINUE TO SUPPORT DRY CONDITIONS AND NEAR
RECORD HIGH TEMPERATURES IN THE 90S AND 100S FARTHER INLAND AWAY
FROM COASTAL INFLUENCE. FUELS CONTINUE TO DRY, BECOMING INCREASINGLY
RECEPTIVE EACH DAY. AN OFFSHORE PRESSURE GRADIENT WILL PROMOTE
PRIMARILY NORTH WINDS OF 15-25 MPH AMID RH OF 15-20% THIS EVENING
INTO EARLY D2/THURSDAY MORNING. WINDS WILL BE STRONGEST IN FAVORED
TERRAIN GAPS AND DOWNSLOPE AREAS IN LA/VENTURA/SANTA BARBARA
COUNTIES.
..PLEASE SEE WWW.SPC.NOAA.GOV/FIRE FOR GRAPHIC PRODUCT
CLICK HERE TO GO TO PREVIOUS BULLETINS.
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