Day 1 Fire Weather Outlook  
NWS Storm Prediction Center Norman OK
0158 AM CDT Fri Aug 21 2026

Valid 211200Z - 221200Z

...Synopsis...
Along the northwestern periphery of an expansive upper ridge over
the West, a midlevel low will track slowly northeastward off the
Pacific Northwest coast. Accompanying this feature, a belt of
enhanced deep-layer south-southwesterly flow will overspread parts
of the central and northern Great Basin. Deep boundary-layer mixing
amid this enhanced flow aloft will yield 15-20 percent RH and around
15 mph sustained south-southwesterly surface winds across parts of
northeast CA, northwest NV, and southern OR. These dry/breezy
conditions atop dry fuels will result in elevated fire-weather
conditions during the afternoon. 

Farther north, midlevel height falls/forcing for ascent preceding
the midlevel low will gradually overspread parts of the Pacific
Northwest late in the forecast period (generally after 06Z). Ample
midlevel moisture and steepening midlevel lapse rates will
contribute to sufficient instability for isolated thunderstorm
development during this time frame, and given receptive fuels,
lightning-induced ignitions will be a concern. Isolated high-based
thunderstorms will also be possible along the Cascades in OR during
the afternoon, though limited large-scale forcing for ascent casts
uncertainty on overall storm coverage compared to areas farther
north late in the period.

..Weinman.. 08/21/2026

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