Day 3-8 Fire Weather Outlook  
NWS Storm Prediction Center Norman OK
0417 PM CDT Tue Jul 29 2025

Valid 311200Z - 061200Z

High pressure over the central US is forecast to gradually weaken
through the end of the week as broad troughing over the Pacific
moves onshore over the West. An embedded shortwave over the
Northwest will lift north and intensify bringing scattered
thunderstorms and dry lightning potential to the region through the
end of the work week. Hot, dry and windy conditions are also
possible over the southern/eastern Great Basin as flow aloft
intensifies this weekend and next week.

...Northwest...
As the shortwave trough continues to lift north within the broader
southerly flow regime, scattered to widespread thunderstorms are
expected late D2/Wed into early D3/Thu. Some of these storms may
occur along and west of the Cascade Crest through D3/Thu afternoon.
Additional storms are likely later into D4/Fri, but PWAT values will
continue to rise as onshore flow increases. This will trend storms
towards a wetter mode and higher precipitation efficiency. With this
increase in rainfall, dry thunder potential appears decreased.
Furthermore, model guidance shows some potential for lingering cloud
cover which may modulate convective coverage. With uncertainty in
storm coverage and dry thunder potential beyond D3/Thu, no
additional 10% areas will be added, though some lightning risk could
persist.

By this weekend, the main trough over the Northwest will begin to
shift eastward allowing stronger westerly winds and a drier air mass
to move onshore. Some dry and breezy conditions may develop over the
Cascades and western Columbia Basin. However, model guidance varies
on the strength of this system into early next week. Though
uncertainty remains, some increase in fire-weather potential is
expected.

...Southern and eastern Great Basin...
As troughing intensifies and moves onshore over the Northwest, flow
aloft will begin to increase over much of the Great Basin and
central Rockies next weekend and early next week. This area has
largely avoided meaningful precipitation over the last several days
and fuels have continued to dry. As winds increase, stronger surface
gusts are expected to develop D5/Sat and beyond. Guidance varies on
the strength of the flow aloft, but ensemble data shows some
potential for 15+ mph surface winds on a widespread basis colocated
with expected low RH late this weekend. Additional active
fire-weather conditions are possible early next week.

..Lyons.. 07/29/2025

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