813
FNUS21 KWNS 211533
FWDDY1

Day 1 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
1032 AM CDT Thu Aug 21 2025

Valid 211700Z - 221200Z

Scattered high-based showers with isolated embedded thunderstorms
are moving northeast over northern Utah, southeast Idaho, and
western Wyoming this morning. Isolated to scattered mixed wet/dry
remain likely, with the best chances and coverage over the central
mountains in Utah through the Uintas and in northwest to
north-central Wyoming. Isolated mixed wet/dry thunderstorms are
possible in portions of western Colorado, but even without
thunderstorm development, enough buoyancy and instability are
present to support deep pyroconvection on active large fires in
western Colorado. Isolated high-based showers and thunderstorms may
continue overnight in portions of central Utah as well.

Locally elevated winds/RH remain likely across southern Idaho into
western Wyoming and across portions of the southern Great Basin onto
the West Slope. Gusty northerly winds are possible late this
afternoon and evening in portions of northwest Colorado, southern
Wyoming, and northeast Utah associated with a cold front.

..Nauslar.. 08/21/2025

.PREV DISCUSSION... /ISSUED 0156 AM CDT Thu Aug 21 2025/

...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.

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

$$