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...

$$