947
FNUS22 KWNS 121958
FWDDY2

Day 2 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0258 PM CDT Fri Jul 12 2024

Valid 131200Z - 141200Z

The current D2 Fire Weather largely remains on track with only minor
adjustments needed to bring isolated dry thunder into portions of
southern California. Sounding analysis supports potential for
high-based storms, with little to no measurable precipitation within
this region. Fuels within this region remain critically dry, further
supported by recent fire activity.

See previous discussion for more information.

..Thornton.. 07/12/2024

.PREV DISCUSSION... /ISSUED 0224 AM CDT Fri Jul 12 2024/

...Synopsis...
Fire weather concerns will continue into the weekend across the
western U.S. - especially across the Great Basin where isolated to
scattered dry thunderstorms are expected to develop by mid-afternoon
and persist into the overnight hours. Continued hot/dry conditions
are expected across much of the West, with breezy winds likely
across portions of the Pacific Northwest and northern Rockies on the
northern periphery of a dominant upper ridge centered over the
southern Great Basin.

...Dry Thunderstorms - Sierra Nevada and the Great Basin...
A weak mid-level low is noted in early-morning water-vapor imagery
off the CA coast to the west of a more dominant upper ridge.
Concurrently, a plume of 0.5-0.9 inch PWAT values is slowly
migrating northward from southern/central CA. This moisture will
continue to spread north over the next 48 hours and will phase with
the mid-level impulse as it moves north Saturday
afternoon/overnight. The combination of increasing mid-level
moisture atop very dry boundary-layer conditions - along with 20-25
knot mean storm motions - will support the potential for dry
thunderstorms. Forecast guidance suggests thunderstorms will
initially develop across the southern Sierra Nevada into the lower
CO River Valley Saturday afternoon around peak heating, slowly
spreading north during the evening and overnight hours. Ensemble
guidance currently depicts low (30% or lower) probability for
wetting rainfall, and recent fuel guidance indicates that
lightning-ignition efficiency is fairly high (15-20%) along the
Sierra Nevada and into central NV/southern OR/ID. Consequently, dry
lightning concerns are likely, and an upgrade to Scattered Dry
Thunderstorms may be warranted if a corridor of higher thunderstorm
potential becomes apparent in high-res guidance.

...Pacific Northwest/northwest Nevada and ID/MT...
Hot/dry conditions are expected to continue across the Pacific
Northwest with another day of RH values in the single digits to low
teens. A belt of strong mid-level flow should reside across the
Cascades/northern Sierra Nevada into the northern Rockies, which
will maintain lee troughing across eastern OR/WA and across the
northern High Plains. A combination of modest gradient winds,
downslope wind enhancement, and deep boundary-layer mixing should
yield areas of 15-20 mph winds coincident with very dry conditions.
Elevated fire weather conditions appear likely with localized
critical conditions possible.

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

$$