370
FNUS21 KWNS 011656
FWDDY1

Day 1 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
1155 AM CDT Tue Jul 01 2025

Valid 011700Z - 021200Z

...CRITICAL FIRE WEATHER AREA FOR SOUTHERN AND CENTRAL NEVADA...

...Northern California...
Isolated dry thunderstorm threat was extended farther south along
the California coastal range with thunderstorm development expected
just north of Napa Valley this afternoon. Similarly, thermodynamic
profiles over the northern Sierra suggests convective development
just north of Lake Tahoe later today, moving into northeastern
California and southern Oregon through the afternoon and evening
hours.

...Southern/Central Nevada...
Critical fire weather conditions with sustained southerly winds of
15-20 mph and daytime relative humidity of 10-15% amid dry fuels
will increase wildfire spread potential across central and southern
Nevada today.

Otherwise, previous forecast (see below) remains largely on track
with additional high-based showers and thunderstorms with potential
lightning ignitions amid receptive fuels over the higher terrain of
northwest Arizona, central Utah into the Upper Snake River Plain and
far southwest Wyoming.

..Williams.. 07/01/2025

.PREV DISCUSSION... /ISSUED 0119 AM CDT Tue Jul 01 2025/

...Synopsis...
An amplified upper trough slowly progressing eastward across central
California will be responsible for supporting mixed dry/wet
thunderstorms across portions of northern California into southern
Oregon, critical fire-weather conditions across portions of southern
and central Nevada, and for pushing enough monsoonal moisture into
portions of Arizona, Utah, and southeastern Idaho to support
lightning over dry fuels.

...Central/Southern Nevada...
Deep boundary layer mixing below strong meridional mid-level flow
will result in dry and windy conditions that overlap with fuels
receptive to wildfire spread (ERCs at or exceeding the 90th annual
percentile). Relative humidity of 5-10% coupled with 25 MPH winds,
possibly gusting to 30 MPH, are anticipated across portions of
central and southern Nevada -- warranting the introduction of
Critical highlights.

...Dry Thunderstorms...
A mix of wet/dry thunderstorms are anticipated across portions of
northern California into southern and eastern Oregon. Thunderstorms
are expected to develop within deep inverted-v boundary-layer
profiles with total precipitable water content between 0.5 - 0.75
in, and 0 - 6 km mean wind speeds of 15-20 MPH. With ERC percentiles
climbing to the 70th-80th annual percentiles, lightning over dry
fuels with little wetting precipitation will pose a fire-weather
risk.

Further east across portions of northern Arizona, western/central
Utah, and far southeastern Idaho, a mix of wet and dry thunderstorms
is expected. ERC fuel percentiles are more significant across this
region, ranging from the 90th annual percentiles to exceeding the
98th annual percentiles across large portions of the region. With
total precipitable water vapor content forecast between 0.5 and 0.8
inches resulting in lower precipitation efficiency, dry lightning
ignitions will be possible.

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

$$