820
FXUS66 KEKA 022019
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
119 PM PDT Sat Aug 2 2025

.SYNOPSIS...Interior thunderstorms around the Trinity Horn will
threaten to continue over the weekend, primarily on Sunday.
Ridging into this coming week will warm temperatures with
potential for another trough next week.


&&

.DISCUSSION...A recurring theme of late afternoon convective
weather will continue to a lesser degree this weekend. The usual
areas around the Klamath Mountains could have showers or
thunderstorms this weekend with extreme NE regions of Trinity
County the most likely location for any shower/thunderstorm
development. The potential for thunderstorms decrease
substantially today 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 Tuesday or
Wednesday of next week. The duration of warmer temperatures
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. Even coastal areas have a potential for
high temperatures reaching the mid to upper 60s by later in the week.
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/early next weekend with a closed 500mb circulation offshore
the California coast and ESE winds aloft.


&&

.AVIATION...18Z TAFs...A trough offshore continues to bring fairly
persistent coastal stratus. The profiler at ACV is showing the
marine layer to around 800 ft. Some lifting is likely, but IFR and
MVFR ceilings are likely for much of the coast into the
afternoon. Some brief scattering is possible, but stratus will
likely make a return in the evening. Mainly IFR to MVFR ceilings
are forecast as the trough approaches the area and lifts ceilings.
Brief periods of LIFR are possible, though unlikely. Visibilities
may drop slightly early in the morning if drizzle develops.
Inland, mostly clear skies are expected outside thunderstorms in
Trinity County. Gusty NW winds of 15-20 kts are possible in the
afternoon in UKI, but these will ease overnight. JB


&&

.MARINE...An upper level trough just off the coast is keeping the
winds around 15 to 25 kt with the stronger winds south of Cape
Mendocino. The waves are mainly short period and driven by the local
winds. The highest waves are found south of Cape Mendocino where
they peak around 7-8 feet. Winds are expected to increase slightly
on Sunday as the upper level trough moves by the area early on
Sunday. Monday the winds are expected to start to diminish, but are
expected to remain in the 10 to 20 kt range through early Thursday.
Stronger northerly winds may return Friday.

The waves are expected to continue to be mainly in response to the
local winds. The 1 to 2 foot southerly swell is currently moving
through the waters and there will likely continue to be some small
southerly swells at times over the next week.

The Tsunami continues to produce small waves. These are mainly less
than 6 inches in Crescent City now. They are expected to continue to
diminish, but may continue to bring some increased currents and
surges for a bit longer. MKK


&&


.FIRE WEATHER...We will continue to include a headline in the
fire weather forecast for isolated thunderstorms and possible new
ignitions. Temperatures aloft and stability will likely increase
today 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, mostly around the Trinity
Horn. 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 Monday for PZZ455-475.

     Small Craft Advisory from 11 PM this evening to 3 PM PDT
     Sunday for PZZ470.

&&

$$

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