016
FXUS66 KEKA 020734
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
1234 AM PDT Thu Oct 2 2025

.SYNOPSIS...Risk of sneaker waves along beaches continues today.
Otherwise, isolated to scattered showers are expected today
before winding down on Friday. Dry weather is forecast for this
weekend and early next week.


&&

.DISCUSSION...Rain showers have mostly eased overnight, but this
will be short lived as an upper trough centered offshore NW of
Washington digs southward this morning. Cold air aloft, 500mb temps
near -20C, will lead to steeper lapse rates. This will lead to
greater rain shower activity, especially in the late morning into
the afternoon. CAMS are largely indicating the bulk of shower
activity over the interior forced by terrain, but are surprisingly
indecisive on what areas will see the bulk of the activity. Some
models show more activity in interior Humboldt and Trinity and some
have more activity in Lake and Mendocino. Regardless, spotty light
precip is expected to continue into Thu night with low level
westerly flow into the terrain. Overall not much widespread rain is
anticipated, but there are few HREF members that indicate isolated
heavier amounts (0.25 inch or more) around the periphery of
Trinity, Mendocino and Lake.

The upper trough will progress into the Great Basin on Friday,
leaving our forecast area under drier and more stable conditions.
Some light showers in the wrap around will be possible along the
eastern periphery of southern Trinity, eastern Mendo, northern Lake
and perhaps over the Alps. Otherwise dry weather is expected Friday
through the weekend. Gusty and potentially strong northerlies are
expected for the coastal waters and coastal high terrain by Sun.

Drying offshore wind will yield clearer skies, especially for
coastal areas over the weekend. Fog and low clouds in the interior
valleys remain a distinct possiblility after multiple days of
rain. If skies remains clear all night, frost or freezing
temperatures in the colder valleys will be possible. NBM is
showing around a 30% chance for low temperatures below 37 degrees
tonight/Friday morning for the coldest valleys (Hayfork, Ruth,
Larabee Valley). Chances rise to around 50% Friday night/Saturday
morning. Rain today would increase the chance for low clouds or
fog in the valleys and lower the chances of frost. Still, with
such a cold and dry airmass, this is something to watch.

Much greater forecast uncertainty crops up early next week with
offshore wind flow diminishing. A southerly wind reversal may
develop. This would likely result in the return of coastal stratus
and fog. Otherwise dry weather expected into mid next week.


&&

.AVIATION...06z TAF...Post frontal conditions have persisted with
only isolated linger showers. Fresh moisture combined with linger
instability has created generally MVFR conditions with
inconsistent ceilings around 3 kft along the coast and in inland
valleys. There is a weak signal (35% chance) that ceilings will
lower to IFR conditions overnight. Any ceilings present around
sunrise will most likely be slow to lift through he day Friday as
more stable conditions try to push clouds lower. There is higher
confidence in VFR conditions returning across the interior by
Thursday night with a shallow surface based marine layer possibly
bringing isolated IFR to LIFR visibilities late in the night. /JHW



&&

.MARINE...Southerly winds over the waters have greatly diminished
overnight with few gusts even over 10 kts and short period seas
generally no more than just a couple feet. That said, seas have
remained steep due to a mid period westerly swell around 14 feet.
This swell will gradually decay through the day Thursday with wave
heights generally below 10 feet by late Thursday afternoon.

Just as the swell decays, gentle southerly winds will gradually turn
northerly. Northerly wind will first increase in the southern waters
with some gusts over 25 kts south of Cape Mendocino during the day
Friday, with moderate to strong northerly winds across all waters by
Saturday generating steep short period seas over 6 feet. There is
some potential (40% chance) for gale force conditions around Sunday
in the southern waters persisting into early next week. /JHW


&&

.FIRE WEATHER...High humidity, breezy winds with periods of rain
expected into Thursday. Drier conditions with lower daytime
humidity is expected to build this weekend and persist into early
next week. Potential for locally gusty north and northeast winds
will increase over the weekend. Much more variable conditions are
probable early next week with signs of southerly wind reversal
developing for coastal areas. ERC`s increase during the weekend
into early next week but remain well below average. North OPS GACC
significant fire potential outlook remains keeps our forecast area
in the little to no risk category except along the edges with the
Sacramento Valley.


&&

.BEACH HAZARDS...S steep mid period westerly swell currently
around 14 feet at 14 seconds will slowly decrease through Thursday
afternoon. While the swell is only producing beach run up to around
18 feet, this is one of the first swells of the season. This means
most areas beaches have a steeper grade that have formed over the
summer, which can make waves especially dangerous and unexpected.
Take extra care if on local beaches this week. /JHW


&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
     Beach Hazards Statement through this afternoon for CAZ101-
     103-104.

NORTHWEST CALIFORNIA COASTAL WATERS...
     Small Craft Advisory until 5 PM PDT this afternoon for
     PZZ450-455-470-475.

&&

$$

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