175
FNUS21 KWNS 171643
FWDDY1

Day 1 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
1143 AM CDT Sun Aug 17 2025

Valid 171700Z - 181200Z

...Dry Thunder Northern Rockies/northern Great Basin...
A mid-level trough and weak frontal boundary interacting with
residual monsoon moisture, along with daytime instability will
contribute to another round of thunderstorms mainly over the
portions of central/southern ID and far northern NV. Higher
atmospheric moisture content with PWAT values around 1.00 inch and
surface dewpoints in the 50s could support wetter rain cores across
central ID. However, faster northeast storm trajectories of up to 30
knots will limit residence time, likely leading to a mixed wet/dry
thunderstorm environment this afternoon. Farther south where monsoon
moisture decreases, isolated dry thunderstorm development and new
lightning ignitions are possible along higher terrain south of the
Snake River Plain into far northern Nevada, where fuels remain
receptive.

...Eastern Great Basin...
Dry and breezy conditions are still expected for much of eastern NV
and west-central UT today aided by broad southwest flow southeast of
the mid-level trough situated over the Northwestern U.S. Sustained
southwest surface winds of 10-15 mph, localized 20 mph in southern
NV/western UT, relative humidity of 10-15 percent range and dry
fuels will support increased fire spread potential.

..Williams.. 08/17/2025

.PREV DISCUSSION... /ISSUED 0200 AM CDT Sun Aug 17 2025/

...Synopsis...
Broad ridging is forecast to expand over the central US today and
tonight as a mid-level trough strengthens over the West. Monsoon
moisture will lift north ahead of the trough and surface cold front
supporting scattered showers and a few dry thunderstorms. Dry and
breezy conditions are also possible over parts of the Southwest.

...Dry Thunder Northern Rockies...
As western US troughing gradually consolidates, stronger mid-level
flow will move eastward across the northern Great Basin and Rockies.
The surface cold front will impinge on the western edge of monsoon
moisture over the regions supporting another day of showers and
thunderstorms. With PWATs near 1 inch, a wetter storm mode is
expected, along with some wetting rainfall. Still, the increased
flow aloft and faster storm speeds could support a few storms with
lower precipitation efficiency. With the threat for lightning
overlapping with drier fuels (especially east) isolated dry
thunderstorms remain possible.

...Eastern Great Basin...
South of the intensifying upper trough, enhanced southwesterly flow
will overspread portions of the Great Basin beneath the western
fringes of the upper ridge. Very warm temperatures are expected and
fuels remain very dry/receptive to spread. A modest increase in
surface winds to near 15 mph is expected through the afternoon along
with RH below 15%. With some record to near record high ERC values
remaining across portions of the Great Basin, a few hours of
Elevated fire-weather conditions are possible.

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

$$