935
FNUS28 KWNS 022154
FWDD38

Day 3-8 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0452 PM CDT Tue Jul 02 2024

Valid 041200Z - 101200Z

An unusually strong ridge of high pressure will dominate the West
Coast synoptic pattern through the extended forecast period. 600 DAM
500 mb heights will allow for extreme heat and very dry surface
conditions to develop over much of the Southwest and Great Basin.
Several weak upper troughs will move along the eastern edge of the
ridge supporting occasional stronger surface winds and some fire
danger. Otherwise, modest synoptic winds will occur under the ridge
over much of the West, with near record temperatures and rapid
drying of fuels likely.

...Northwest and Great Basin...
As the strong ridge of high pressure intensifies this week, several
modest perturbations will move around the top and eastern periphery
of the ridge over the Northwest and northern Great Basin late in the
week and into the weekend. With several days of hot and very dry
conditions expected prior, gusty downslope winds of 15-25 mph could
support localized fire-weather concerns across the lee of the
Cascades and western Columbia Basin D3/Thursday and D4/Friday.
Confidence in the coverage of stronger winds and uncertainties in
fuel availability will preclude probabilities for now.

More significant fire-weather concerns appear likely this weekend as
the upper trough and associated jet streak move south into the Great
Basin. A wind shift at the surface will accompany the upper trough
as breezy northwest surface winds to 20-25 mph develop behind it
across parts of southern ID, northern NV and western UT D5/Saturday.
Very warm temperatures and low RH of 10-15% will precede the
increase in winds, supporting an increased risk for critical
fire-weather conditions.

D6/Sunday and beyond, confidence in the evolution of the upper ridge
and the associated synoptic pattern decreases substantially. Some
risk for dry and breezy conditions may continue with northwesterly
flow aloft across parts of the Southwest and Great Basin. However,
the spatial coverage and uncertainties in fuels lend low confidence
in the potential for critical fire-weather conditions at this time.

...Southern CA...
Periodic offshore and terrain-enhanced flow is expected over parts
of southern CA late this week. South of the ridge of high pressure,
light easterly mid-level winds are expected to overspread the Desert
Southwest and southern CA. While weak, somewhat enhanced low-level
pressure gradients may support a few hours of breezy downslope winds
near 20-25 mph overnight D3/Thursday through D5/Friday. With very
hot and dry conditions likely beneath the ridge, localized
near-critical fire-weather conditions may occur with these weak
Sundowner winds and across parts of the southern CA Valleys. Winds
should dissipate this weekend as the upper ridge shifts eastward and
the weak upper-level support lessens.

..Lyons/Halbert.. 07/02/2024

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

$$