308
FXUS66 KEKA 160808
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
1208 AM PST Sun Nov 16 2025

.SYNOPSIS...Rain chances increase in Lake, Mendocino, and Trinity
early this morning. More widespread rain and gusty winds are
forecast midday through Monday. An extended period of cold
overnight lows with widespread frost and interior freezing
temperatures will begin overnight Monday.


&&

.DISCUSSION...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 0.10" forecast.

A stronger frontal system will increase rain chances beginning by
midday today. A shortwave trough and associated well defined frontal
boundary will quickly move over the N CA coast later this
afternoon/evening with bursts of heavy precipitation rates (0.3 to
0.5 inches per hour). Forecast rainfall totals today 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 level hydrological issues.

Elevated instability expected with this trough before it likely
evolves into a closed low off the Mendocino coast as it dives south
of Point Arena. Wind gusts of 30 to 40 mph are expected as the front
passes over the areas this afternoon/evening. The highest
probabilities for wind gusts over 30 mph are for the coastal areas
near Cape Mendocino and southward. There will be increased
instability and forcing around the developing low closer to
Mendocino and Lake counties. This increased instability brings
higher chances for prolonged breezy winds. Northerly winds build
swiftly 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.

Behind the front a much colder and drier airmass will be over our
area. Widespread frost and possibly freezing temperatures can be
expected Monday night and Tuesday night if cloud coverage holds off.
NBM shows high chances (>=60%) for temperatures below 36F in
Trinity, eastern Mendocino, and Lake counties. Chances for freezing
temperatures less than 32F are ~25% 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. High temperatures will also be
cooler, with even the warmest valleys struggling to reach 60.
Overnight lows will remain chilly through next week as values
begin to align closer to 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. JJW


&&

.AVIATION...(06Z TAFS)...IFR cigs returned for coastal terminals
(KACV and KCEC) overnight. Occasional IFR cigs expected for coastal
terminals through the morning hours. SE winds proceeding a frontal
boundary should scour out the moist air and cigs should lift up to
MVFR. Incoming light rain ahead of the front may result in periods
of IFR vsbys and cigs aft 18z. Winds shift rapidly to NW late Sunday
evening. Once again periods of IFR in moderate to brief heavy rain
is expected. For UKI, MVFR cigs probable early morning hours of
Sunday. Light rain aft 20z is forecast to increase in intensity aft
02z and IFR cigs and vsby expected in moderate to brief heavy rain.


&&

.MARINE...A cold front will move across the area Sunday night.
Northerly winds will rapidly increase behind the front with gale
force gusts probable by mid to late evening for the outer waters.
High resolution and global models continue to depict a wide range of
scenarios Sunday evening. Some are faster and stronger while others
are slower and weaker. HREF chances over a 2-4 hour window with
neighborhood radius of 10km indicate a large swatch of 70% chances
for gusts over 34kt by mid to late in the outer waters. Inner waters
are less certain with timing, however chances for gusts > 34 kt
increase to 70% or more late evening and after midnight. Very steep
northerly wind waves onto top of a large short period NW swell
around 15-17 ft at 12-14 seconds will also make for exceptionally
hazardous ocean conditions Sunday night into Monday morning. General
consensus amongst the global and high resolution model guidance is
for northerly conditions to persist through Monday, though the peak
of the gales will likely occur Monday morning. Seas will still be
quite elevated and steep. Thus, will follow the gale with a warning
for seas. Conditions should calm down on Wed, however another
vigorous front and low pressure system will rapidly develop and
generate more impactful winds and seas by Thu.


&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
None.
NORTHWEST CALIFORNIA COASTAL WATERS...
     Gale Warning from 11 PM this evening to 11 AM PST Monday
     for PZZ450.

     Hazardous Seas Warning from 11 AM to 10 PM PST Monday for
     PZZ450-470.

     Gale Watch from late tonight through Monday afternoon for
     PZZ455.

     Gale Warning from 9 PM this evening to 11 AM PST Monday for
     PZZ470.

     Small Craft Advisory until 3 AM PST early this morning for
     PZZ475.

     Gale Warning from 9 PM this evening to 6 PM PST Monday 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