201
FXUS66 KEKA 152228
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
228 PM PST Sat Nov 15 2025

.SYNOPSIS...The break in wet weather and above average
temperatures is coming to an end. Rain chances increase in Lake,
Mendocino, and Trinity this evening and overnight. More widespread
rain and gusty winds are forecast Sunday into Monday. An extended
period of cold overnight lows with widespread frost and interior
freezing temperatures will begin overnight Monday.


&&

.DISCUSSION...A mostly dry day is expected until this evening,
when a cutoff low in southern California moves northward. Light
rain is possible on the western edge of this low this evening and
overnight. The highest chances are in Lake, eastern Mendocino, and
Trinity Counties. Rain amounts are fairly meager for this first
round, with generally less than a 1/4 inch forecast.

A stronger frontal system will increase rain chances throughout the
day on Sunday. A shortwave trough and associated well defined
frontal boundary will quickly move over the N CA coast Sunday
afternoon/evening. A burst of heavy precipitation rates (0.3 to 0.5
inches per hour) can be expected with the frontal passage Sunday
afternoon through Sunday night. Forecast rainfall totals Sunday
into Monday have increase to a broad 1-2 inches, with isolated
southwest facing higher terrain to receive 2.5 inches. Though
these totals are relatively low, areas that experience the maximum
estimated rates may see some brief minor/nuisance level
hydrological issues.

There will be some elevated instability with the trough, which
will likely be evolving into a closed low near or south of the
Mendocino coast as it dives south past Point Arena. Wind gusts of
30 to 40 mph can be expected with the frontal passage Sunday
afternoon through Sunday evening. The highest probabilities for
wind gusts over 30 mph are for the coastal and areas over Cape
Mendocino and southward. There will be increased instability and
forcing around the developing low closer to Mendocino and Lake
counties. This brings higher chances for more prolonged breezy
winds. Winds sharply shift northerly behind the front (near 10 pm
Sunday) as the low moves south. These northerly winds will be
breezy (20-30 mph gusts) through Monday afternoon. The environment
will also be sufficient for thunderstorm development for coastal
areas around and south of Cape Mendocino.

Snow levels are likely to be high at 4500-5000 ft, but a dusting
to an inch of snow is possible at Scott Mountain Pass on Highway
3. Lingering showers may continue through the day Monday before
tapering off Monday night.

The upper-level trough behind the front will bring a much colder and
drier airmass. Widespread frost and possibly freezing temperatures
can be expected Monday night and Tuesday night. NBM shows high
chances for temperatures below 36F in Trinity, eastern Mendocino,
and Lake counties. Chances for freezing temperatures less than 32F
are 50 to 60% in the coldest valleys of Trinity and Mendocino
counties. Wednesday will have the coldest morning, and if offshore
flow is weak enough, areas of frost will be likely over coastal
areas as well. There is currently a high chance (80%) for a
minimum temperature below 37F for isolated portions of the coast
such as around McKinleyville. High temperatures will also be
cooler, with even the warmest valleys struggling to reach 60.
Overnight lows will remain chilly through next week, but values
will nearly align with seasonal norms.

Most ensemble members are in agreement in an additional system
arriving late next week, returning wet weather to the area.
Confidence on impacts is low at this point, but rain, gusty winds,
and mountain snow are all possible. Stay tuned. JB/JJW


&&

.AVIATION...LIFR conditions developed overnight across the
interior valleys, including at UKI. Fog and low clouds across the
interior valleys dissipated between 18Z and 20Z today. Mostly VFR
conditions are then expected for all terminals through at least
3Z this evening. Conditions will most likely deteriorate at
coastal aerodromes after 03Z to 06Z Sun as an upstream trough
induces a push of shallow moisture onto the coast. Winds are
forecast to remain light under 10kt or calm. /ZVS


&&

.MARINE...Northerly winds will increase in the lee of Cape Mendo
with localized gusts to 30 kt in the afternoon and evening. Steep
waves up to 6 ft are expected to build in lee of Cape Mendo by this
evening. A small craft advisory has been hoisted for the southern
outer waters. These conditions may briefly extend into the inner
waters during the evening Sat. Otherwise calmer conditions with
lighter northerlies expected north of Cape Mendo. A mix of small
wave groups will also continue to subside today.

Next frontal system is forecast to rapidly approach on Sunday.
Strong to near gale sustained winds are forecast to develop in the
wake of the front Sunday evening into Monday. Models are now in a
better agreement with gale force gust N-NW winds up to around 40 kts
across the outer waters, with the strongest south of Cape Mendocino
on the backside of the front. Gale Watches are out for the outer
waters and the southern inner zone. A more brief period of gale
conditions is likely in portions of the northern inner zones as
well. A Hazardous Seas Watch is up for the zone (450) to account
for the potential gale conditions, large steep waves, and confused
seas state.

A large mid to short period W-NW swell will also arrive by Mon
and seas will once again become hazardous. Seas could reach 18-20
ft by early Monday, especially across the southern outer waters.
Another deep low will rapidly develop and approach on Wed and the
risk for southerly gales with large steep waves will once again
increase and may persist into Thu. DUG/JJW


&&

.BEACH HAZARDS...A larger NW swell will move through the
waters Sunday evening through Monday, resulting in building surf
along the beaches and increasing the potential of sneaker waves.
Breaking waves will increase rapidly Sunday evening, reaching as
high as 14 to 19 feet by Sunday evening along the northwest
facing beaches. Sneaker waves are a unique hazard, with many
minutes between waves. Pay attention and stay above the high water
line and any wet sand to stay safe. If the ground is wet, waves
have surged there recently. Stay safe and never turn your back on
the ocean! /ZVS


&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
None.
NORTHWEST CALIFORNIA COASTAL WATERS...
     Gale Watch from Sunday evening through Monday morning for
     PZZ470.

     Small Craft Advisory until 2 AM PST Sunday for PZZ475.

     Gale Watch from Sunday evening through late Monday night
     for PZZ475.

&&

$$

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