960
FNUS21 KWNS 021601
FWDDY1

Day 1 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
1101 AM CDT Tue Sep 02 2025

Valid 021700Z - 031200Z

The previous forecast largely remains on track with only minor
adjustments made to account for recent convective trends. Through 15
UTC this morning, radar rainfall estimates and lightning data
suggest a mix of wet and dry thunderstorms is ongoing across the
Central Valley. Additional thunderstorm development remains likely
through the evening hours across northern CA, northwest NV, and
central OR. While 12 UTC guidance has captured the ongoing activity
well, most solutions initialized with a notable warm/dry bias across
northern CA and adjacent portions of OR/NV, suggesting that moisture
quality may be slightly better than depicted by morning solutions.
Additionally, mid/high-level cloud cover associated with the ongoing
showers/thunderstorms will continue to spread north and may modulate
diurnal heating/mixing to some degree over parts of northern
CA/southern OR. These factors, coupled with forecast PWAT values
between 0.6 to 0.8 inches, hint that a mix of dry/wet thunderstorms
is probable for northern CA/southern OR with an increasing chance
for dry lightning with north and eastward extent if/where storms can
develop ahead of the approaching cloud cover.

..Moore.. 09/02/2025

.PREV DISCUSSION... /ISSUED 0155 AM CDT Tue Sep 02 2025/

...Synopsis...
A weak upper-level low will move northward across northern
California into the Pacific Northwest today through D2/Wednesday,
with increases in moisture and forcing leading to thunderstorm
development. Precipitable water values will approach 0.60-0.90",
decreasing with eastward extent across eastern Oregon/western
Nevada. Faster storm motions around 15-20 kts will likely lead to a
mix of wet/dry thunderstorms. New starts will be possible where
little to no precipitation occurs, with ERCs around the 80th-90th
percentile across portions of these regions. An isolated dry
thunderstorm area was maintained with this outlook across portions
of northern California into western Nevada an northward into central
Oregon.

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

$$