141 

FNUS21 KWNS 151633

FWDDY1



Day 1 Fire Weather Outlook  

NWS Storm Prediction Center Norman OK

1132 AM CDT Thu Oct 15 2026



Valid 151700Z - 161200Z



...CRITICAL FIRE WEATHER AREA FOR WESTERN L.A. COUNTY AND

SOUTHEASTERN VENTURA COUNTY...



...17Z Update...

...Southern California...

The forecast remains on track as critical fire weather conditions

continue through the late morning hours across western L.A. county

and southeastern Ventura county as a dry, offshore flow pattern

persists over the region. East-northeast winds of 10-20 mph have

been observed in Simi Valley and adjacent mountain ranges with

current surface observations showing sustained east-northeast winds

of 25-35 mph with gusts of 45-55 mph in favored terrain gap areas

and exposed ridgetops. Winds will briefly diminish this afternoon

before ramping up again tonight into D2/Friday morning. Current RH

in the 15-20% range will fall to as low as 10% in some valleys this

afternoon. An elevated fire weather threat surrounds the corridor of

stronger winds across southern CA.



...Sierra Nevada, portions of the Sacramento Valley and Napa

Valley...

Farther north, the broader offshore pattern will impact the western

slopes of the Sierra Nevada today. Downslope east-northeast winds of

10-15 mph (locally 20 mph) along with RH as low as 15% this

afternoon are expected after poor RH recoveries below 30% this

morning in some locations. Similarly dry, northerly to northeasterly

flow will affect portions of the Sacramento Valley and Napa Valley

through this afternoon as RH falls to around 10% this afternoon in

lower elevations.



..Williams.. 10/15/2026



.PREV DISCUSSION... /ISSUED 0107 AM CDT Thu Oct 15 2026/



...Synopsis...

A mid-level low over the central Plains will weaken and transition

to an open wave, quickly becoming absorbed within defined troughing

over the Upper Midwest. Meanwhile, a cutoff low will detach into the

Desert Southwest as surface high pressure migrates into the

Intermountain West and central CONUS. As a result, an increasing

offshore pressure gradient will promote a fire weather threat for

portions of southern CA that have not seen recent rainfall. 



...Southern California...

The fire weather threat will increase markedly early this morning

into the early afternoon hours as offshore flow accelerates across

portions of southern CA. Resultant east-northeast winds of 15-25 mph

will emerge with related downslope drying from a dry airmass

originating from the Colorado Plateau, allowing for RH reductions as

low as 10%. A corridor of stronger east-northeast winds of 20-30 mph

with gusts of 40-50 mph coupled with low RH will support critical

fire weather conditions in the Simi Valley area of western L.A.

county and southeastern Ventura county.



...Sierra Nevada, portions of the Sacramento Valley and Napa

Valley...

Increasing easterly downslope flow and drying into the Sacramento

Valley will promote elevated fire weather conditions for the Sierra

Nevada foothills this afternoon. Poor overnight RH recoveries with

some locations not exceeding 30% will precondition fuels where ERCs

are at the 80-90th percentiles. East winds of 10-15 mph (locally

20-25 mph in favored valley corridors) and daytime RH of 15% will

support an Elevated fire weather threat.



A building ridge aloft supporting above normal temperatures and very

dry conditions along with offshore flow trajectories will bring a

fire weather threat to portions the Sacramento Valley and adjacent

Napa Valley area. North winds of around 15 mph in the Sacramento

Valley will transition to east-northeast over Napa Valley and nearby

coastal ranges as RH falls to as low as 10% by this afternoon.



...Please see www.spc.noaa.gov/fire for graphic product...



$$