098
FXUS66 KEKA 290907
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
107 AM PST Thu Jan 29 2026

.SYNOPSIS...A warm up for the next few days will be gradual.
Moisture will make its way into the area towards the end of the
weekend with the arrival of a frontal boundary and dynamic
forcing, light rain is likely Sunday.


&&

.DISCUSSION...Broad flat ridging will remain over the the area
through the end of the week. A long fetch of southwesterly
moisture with above normal PWATS will remain offshore through the
end of the week. Minor short wavelength disturbances in the
southwest-westerly flow aloft may result (10-20% chance for a few
hundredths) in a few light showers or sprinkles mostly across Del
Norte and northern Humboldt through Friday, particularly over the
highest terrain. More amplified flow is forecast to occur Fri-Sat
as another trough digs offshore over the northeast Pacific and
precip chance along the OR/CA border is forecast to diminish.

Otherwise, dry weather with generally above normal daytime high
temperature is forecast for the rest of the week. Occasional mid
and high clouds cutting over the flat ridge will hamper the
longwave cooling and overnight low temperatures will most likely
not be as cold. A more significant counter to the longwave cooling
will be abundant low cloud cover and fog in the interior valleys.
High resolution mesoscale models as well as BUFKIT profiles show
lower boundary layer humidity tonight and low clouds may not be as
extensive after the moist air push last night. Fog and low clouds
will likely form again in the valleys Thu night/Fri AM, especially
in Trinity, Humboldt and northern Mendo.

Days 3-7: Global models continue to indicate another shortwave
trough approaching NW California coast this weekend. Surface
frontal passage appears to hold off til Sunday when most of the
precip is expected. A faster scenario suggests rain arriving
earlier, Sat night. With a dominant blocking pattern, this does
not appear as likely as a slower progression. Multi-model
ensemble (NBM QMD) continues to indicate a 40-60% chance for 0.25
inches or more in 24 hours ending 4 PM Sunday or 4 AM Monday for
mainly the northern most zones. There is a 13-23% chance for 1" in
24 hours over Del Norte mountains and SW Humboldt (King Range)
for the same 24 hour time periods. Generally lighter amounts of
rain are forecast for eastern valleys of Trinity and southern
portions of Lake and southern Mendo where chances for 0.10 inches
in 24 hours are around 20-45% ending 4 AM Monday. Snow levels
appear quite high when most of the precip arrives, generally above
6kt on Sunday, lowering to 5kft in the cooler air after frontal
passage by Monday morning. Southerly winds may also become gusty
for the higher terrain in advance of the surface front Sat night
or Sun morning. Deterministic GFS 925mb winds do increase to 40-45
kt offshore Sat evening. ECMWF ensemble meteograms and EFI are
not suggesting strong southerly winds with the front at this
time. NBM 24 hour probabilities indicate a 10-30% chance for
gusts to 40 mph or more over the ridges of Del Norte and SW
Humboldt Sat Night and Sun morning. Stay tuned for fine tuning of
the forecast. Lingering showers will be possible on Monday before
a ridge aloft amplifies and northerly to northeasterly surface
flow develops and we stay dry for a day or two and perhaps most of
next week.



&&

.AVIATION...Cold air moving east of the area has helped solidly turn
wind out of the east. In turn, this has helped generate mostly dry
and clear VFR conditions all along the coast. There is some slight
potential for fog formation tonight in interior valleys such as near
Ukiah, but passing high level clouds have even reduced that to a 50%
chance. Widespread VFR conditions will continue all through the day
and evening Thursday. /JHW


&&

.MARINE...Currently gentle southerly winds throughout the waters
will persist until Saturday with only very isolated gusts over 20
kts int he far outer waters. That said, a persistent series of long
period westerly swells will maintain a steep sea state through
Friday morning. COmbined sea will most likely barely drop below 10
feet Friday, but another westerly swell will build in and keep sea
no shorter than about 8 feet into the weekend. Sea will most likely
very briefly calm Saturday night into Sunday, but a weak front
crossing the area Sunday will most likely rebuild steep short period
seas. Yet another round of steep, long period swells will build
behind the frost once again building over 10 feet into early next
week. /JHW


&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
None.
NORTHWEST CALIFORNIA COASTAL WATERS...
     Small Craft Advisory from 3 AM Thursday to 3 AM PST Friday
     for PZZ450.

     Small Craft Advisory until 3 AM PST Friday for PZZ455.

     Small Craft Advisory until 3 AM PST Friday for PZZ470-475.

&&

$$

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