370
FXUS66 KEKA 250731
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
1231 AM PDT Fri Jul 25 2025

.SYNOPSIS...Thunderstorms are possible in the interior Friday.
Near normal to slightly below normal temperatures expected this
week. Temperatures trend slightly upward early next week.


&&

.DISCUSSION...Early Friday, there are hints of showers from the
Sierras moving into Lake or eastern Mendocino counties in the
early morning. These are likely not going to be thunderstorms, but
a stray shower is possible. In general, the upper-low inches more
northeasterly, bringing a similar setup to yesterday for Friday,
but moves slightly south and east. Confidence has increased on
thunderstorms forming across Trinity County, eastern Mendocino,
and northern Lake Counties. CAPE may be even higher Friday
(nearing 1000 J/kg) with DCAPE remaining near 1000 J/kg. Higher
shear in the Yolla Bollys may allow for some longer-lasting
storms, but elsewhere shear remain weak. Storms will likely form
and collapse quickly, bringing gusty outflow winds possibly in
excess of 50 mph. PWATs of an inch could support periods of heavy
rain.

The low moves to the east Saturday, bringing most mid-level moisture
with it. Thunderstorm chances significantly decline, and if any
form, the Trinity Horn is the most likely area. Sunday and into the
middle of next week high pressure is expected to generally remain
east of the area. This will keep temperatures near seasonal normals
with highs in the upper 80s to low 90s. Thunder potential generally
looks to remain low. Ensembles are hinting at another upper-low
forming right off the coast, which may return thunderstorm chances
mid next week, and this will need to be watched. JB


&&

.AVIATION...(00Z TAFs) Fog entering the river valleys shows a
40-50% probability of reaching KUKI up the Russian River early
Friday morning leading to potential IFR conditions. This will
depend largely on how quickly light the north wind will decrease,
and perhaps become variable or even turn to the south. Stratus is
expected to be stubborn along the coast for Friday, and any
clearing will be short- lived. Visibility will be a difficult call
for the coast, but LIFR conditions should be primarily as a
result from low ceilings more than low visibility. DS/MH


&&

.MARINE...An upper level cutoff low will lurk off the Central
California Coast and will remain in the vicinity through Friday and
develop into an open trough for the weekend. This will continue to
weaken the surface pressure gradient, holding winds to gentle to
moderate levels. Seas 2 to 5 feet are expected, with the lightest
conditions expected nearest the coast. Winds will be broadly
northerly with south/southwest winds likely directly adjacent to the
coast, especially overnight. The northerlies will begin to slightly
increase Friday, mainly through the southern outer zone, and likely
remaining mainly below 20 kts through the weekend, except for a
small area south of Cape Mendocino where wind gusts will increase to
20 to 25 KTS from the north/northwest. DS/MH


&&

.FIRE WEATHER...Friday, isolated to scattered thunderstorms shift
south and east with the highest confidence in Trinity, eastern
Mendocino, and northern Lake. Isolated storms are possible in
eastern Humboldt, as well. Again gusty, erratic outflow winds of
50 mph are possible and a brief heavy downpour is not out of the
question. A Red Flag Warning has been issued for abundant
lightning in Trinity, eastern Mendocino, and northern Lake
Counties. Thunderstorm chances decrease this weekend.

Outside of thunderstorms, winds are generally expected to be fairly
light and terrain driven. Interior Temperatures are generally
expected to be around or slightly below seasonal normals with highs
in the 80s to low 90s. Dry afternoon RHs in the 20s are possible in
the eastern portions of the area, but good overnight recoveries are
likely. JB


&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
     Red Flag Warning from 11 AM to 11 PM PDT Friday for CAZ212-
     277-283.

NORTHWEST CALIFORNIA COASTAL WATERS...
None.
&&

$$

NOTE: The full forecast discussion is now regularly issued between
10 am/pm and 1 pm/am. Additional updates will be issued as needed.

Visit us at https://www.weather.gov/eureka

Follow us on Facebook and Twitter at:
https://www.facebook.com/NWSEureka
https://www.twitter.com/NWSEureka

For forecast zone information
see the forecast zone map online:
https://www.weather.gov/images/eka/zonemap.png