####018001957####
FNUS21 KWNS 210657

FWDDY1



Day 1 Fire Weather Outlook  

NWS Storm Prediction Center Norman OK

0156 AM CDT Thu Aug 21 2025



Valid 211200Z - 221200Z



...Synopsis...

A strong ridge of high pressure will remain in place over much of

the west today and tonight. Beneath the ridge, hot conditions are

expected with near record high temperatures. Additionally, monsoon

moisture will move northward along the western edge of the ridge

supporting shower and thunderstorm chances across portions of the

West.



...Great Basin and northern Rockies...

At the nose of the monsoon surge, PWAT values are likely to be

between 0.5-0.8" with a dry sub-cloud layer and steep low-level

lapse rates over portions of Nevada, into Idaho and Wyoming. Storm

development is expected along the higher terrain and near a

stalled/weakening cold front by early afternoon. Despite slower

storm motions and isolated coverage, little wetting rainfall is

expected from any of these storms. This should support isolated dry

thunderstorm potential with dry fuels in place.



Elsewhere, localized dry and breezy conditions are possible over

parts of the Snake River Plain, southern Great Basin and northern

Colorado this afternoon. While occasional gusts to 15-20 mph

overlapping with low RH cannot be ruled out, the coverage of

elevated fire-weather potential should remain low/localized.



...California...

In addition to the risk for very isolated thunderstorms, hot, dry

and unstable conditions are expected across much of the west and

southern CA. Locally breezy winds are possible near a thermal trough

with very warm temperatures expected over much of the West. Steep

mid-level lapse rates and very weak buoyancy could also support some

plume dominated fire growth and pyroconvection near large active

fires.



..Lyons.. 08/21/2025



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



$$

####018001850####
FNUS22 KWNS 210658

FWDDY2



Day 2 Fire Weather Outlook  

NWS Storm Prediction Center Norman OK

0157 AM CDT Thu Aug 21 2025



Valid 221200Z - 231200Z



...Synopsis...

As the upper ridge persist over the West, several subtropical

perturbations will arrive from the south, ushering in another surge

of monsoon moisture. Isolated thunderstorms are likely across the

southern Sierra and into parts of the Great Basin Friday. With very

warm surface temperatures and dry sub-cloud layers, little wetting

rainfall is expected. This should allow for isolated dry lightning

atop receptive fuel mainly over portions of California and Nevada

where fuels are most receptive. Some localized dry and breezy winds

may also occur outside of the thunderstorms over the central great

Basin Friday.



Over the southern Great Basin and Southwest, higher PWATs near 1

inch are expected. Isolated to widely scattered thunderstorms are

likely through the afternoon. However, a wetter storm mode is more

probable across northern Arizona, southern Utah and western

Colorado, where fuels are also less receptive.



...California...

Isolated thunderstorms are likely in portions of southern California

mountains and over the Mojave. A wetter mode is expected with max

PWATs near 1.2 to 1.3 inches and little in the way of steering flow.

However, cloud bases are likely to be over 3-km with a hot/dry

sub-cloud layer limiting some precipitation efficiency. Sporadic dry

strikes re possible given the degree of extreme heat and dry fuels

but coverage is not expected to reach 10% or greater. Additionally,

very hot, dry and unstable conditions may support plume dominated

fire behavior with existing large fires.



..Lyons.. 08/21/2025



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



$$