195
FNUS22 KWNS 131958
FWDDY2

Day 2 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0257 PM CDT Sat Jul 13 2024

Valid 141200Z - 151200Z

A small Elevated area was introduced across the Columbia Basin west
of the Cascades in Washington. In this region, afternoon relative
humidity reductions to 10-15 percent will overlap winds around 15-20
mph (locally higher). After several days of above average
temperatures and dry conditions, fuels within this region are
critically dry and support risk for fire spread. Critical conditions
will be possible where stronger winds do occur, though this threat
remains too localized to include any areas at this time.

Otherwise, the previous Elevated region from eastern Oregon into
southern Idaho was expanded slightly to include more of the Snake
River Plain where winds have trended upward. See previous discussion
for more information on dry thunderstorm chances.

..Thornton.. 07/13/2024

.PREV DISCUSSION... /ISSUED 0121 AM CDT Sat Jul 13 2024/

...Synopsis...
Dry thunderstorms will continue to be the primary fire weather
concern for Sunday across much of the western CONUS, though areas of
dry/windy conditions are also probable across parts of southeast OR
into southern ID.

...Dry Thunderstorms - Great Basin/Pacific Northwest...
Lift ahead of a weak mid-level perturbation is expected to
overspread the northern Great Basin and Pacific Northwest through
peak heating Sunday afternoon. A plume of 0.5-1.0 inch PWAT values
currently advecting north into the Great Basin is forecast to be in
place ahead of this ascent, and will support the potential for
isolated to scattered thunderstorms. Dry low-level conditions and
storm motions near 20 knots should support the potential for dry
lightning. While convection is anticipated across a broad swath of
the West, dry thunderstorm coverage may be slightly higher across
portions of the northern Great Basin/Pacific Northwest on Sunday as
compared to today/Saturday while the mid-level perturbation moves
north. Latest ensemble guidance shows very low (30% or lower)
probability for wetting rainfall across the delineated
dry-thunderstorm risk area where ERC values are near/above the 90th
percentile based on recent fuel guidance.

...Southeast Oregon into southern Idaho...
Subsequent days of mid-level diabatic heat release associated with
isolated to scattered thunderstorms under the upper ridge is
forecast to result in a gradual de-amplification and eastward shift
of the ridge into the Four Corners by Sunday afternoon.
Concurrently, most model solutions depict an upper shortwave trough
moving into the northern Rockies out of Canada, which will support
lee troughing along the northern High Plains. The combination of the
eastward shift of the upper ridge and deepening surface trough
should result in a broad region of around 15 mph winds across the
Great Basin, northern Rockies, and High Plains. Thunderstorm
development over the next 48 hours is not expected to appreciably
modify the very warm/dry air mass currently in place, so
single-digit to low-teen RH values, combined with modest gradient
winds, should result in a broad swath of localized/transient
elevated conditions. Elevated highlights are maintained/expanded
from roughly the Harney Basin in southeast OR into the Snake River
Plain of southern ID, where regional topographic effects should
result in corridor of slightly stronger (15-20 mph) winds for a few
hours Sunday afternoon (though this may be conditional on minimal
cloud cover from developing convection).

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

$$