223
FXUS66 KEKA 011928
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
1228 PM PDT Fri Aug 1 2025

.SYNOPSIS...Chance of thunderstorms over the interior of Northwest
California today. Storms may produce gusty outflow winds, heavy
rain and hail. Interior thunderstorms will be possible over the
weekend, primarily on Sunday.


&&

.DISCUSSION...A recurring theme of late afternoon convective
weather continues today. The usual areas of the eastern flank in
our CWA to include northern Trinity mountains and the eastern
fringes of Del Norte and NE Humboldt along the Siskiyou County
border. Potential for thunderstorms decrease substantially on
Saturday with drier westerly flow spreading across the area and
higher 500mb heights. A colder trough will approach on Sunday
bringing yet another round of showers and thunderstorms to the
interior mountains. Otherwise, this trough will bring cooler temps
and gusty westerly and northwesterly winds Sun and into Mon.

Interior temperatures will likely begin to warm by mid next week.
How warm remains uncertain. 500mb heights pump up to 588DM or
more by late next week and suspect some of the typically hot
valley locations will reach or exceed 100F. The risk for a long
duration heat wave may be mitigated by persistent and frequent
troughs busting down on the ridge from the NW. Deterministic
models are starting to indicate a flow pattern favorable for more
interior convection and thunderstorms late next week with a closed
500mb circulation offshore the California coast and ESE winds
aloft.


&&

.AVIATION...18Z TAFs...Coastal stratus has started to erode late
this morning. The profiler at ACV is showing a marine layer around
700 ft. While some lifting is possible in the afternoon, ceilings
are likely to remain IFR to MVFR. In the interior, outside of the
slight chance for thunderstorms in Trinity County, mostly clear
skies and breezy northwesterly winds are expected this afternoon.
This evening, winds ease and stratus returns to the coastal
terminals. Models are hinting at a shallower marine layer, but an
approaching trough may actually deepen the marine layer. Ceilings
are likely to remain in the IFR or MVFR categories, with brief drops
to LIFR possible. Reduced visibilities are also possible, though
confidence is lower on how low they will drop. Higher ceilings and
visibilities are likely by the late morning. JB

&&

.MARINE...An upper trough continues to keep winds relatively
subdued, especially north of Cape Mendocino. Peak afternoon
northerly gusts of 15-25 kts are still possible, with locally
stronger winds possible in the lee of Cape Mendocino. Seas remain
primarily wind driven, with steep seas of up to 7 ft possible south
of Cape Mendocino. These conditions continue into the weekend and
into early next week.

Lingering tsunami waves continue to show on the tide gauges along
the coast, especially around Crescent City. Even though heights are
less than 1 ft, increased currents and surges are still possible.
These waves will continue to gradually subside over time. JB

&&


.FIRE WEATHER...We will continue to include a headline in the
fire weather forecast for isolated to scattered thunderstorms and
possible new ignitions. Another trough will approach on Friday in
the SW flow aloft. This should maintain the threat for storms and
isolated dry strikes for the Klamath Mountain, mostly in Trinity
County. Temperatures aloft and stability will likely increase on
Saturday and result in a significant reduction in thunderstorms
probabilities for our forecast area. A short wavelength trough
will approach on Sunday and then progress across the area Sunday
night. Granted the trough may slow down and arrive as late as
Monday. This trough will bring another round of showers and
thunderstorms for the Klamath Mountains. This trough on Sunday
will likely induce stronger westerly to northwest winds for our
typically dry and windy areas; Lake, southern Mendocino and
eastern Trinity.


&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
None.
NORTHWEST CALIFORNIA COASTAL WATERS...
     Small Craft Advisory until 3 PM PDT Sunday for PZZ455-475.

&&

$$

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

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https://www.weather.gov/images/eka/zonemap.png