011
FXUS66 KEKA 212255
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
255 PM PST Fri Nov 21 2025

.SYNOPSIS...Cool and clear conditions will continue Saturday. Winds
turning onshore will likely help form a marine layer early Sunday
with light drizzle and rain along the North Coast. Clearer
conditions will return early next week alongside another risk of
interior frost.


&&

.DISCUSSION...Cool and clear conditions have built all
across the area. Clear skies have returned even for the coast with
conditions modestly warming into the upper 50s to mid 60s. Patchy
frost mixed with fog this morning in some interior valleys in
Trinity and Mendocino Counties. Some frost will be possible (30%
chance for valleys in Trinity and Northern Mendocino) again tonight,
but significantly warmer temperatures combined with similar
dewpoints in the upper 30s will most likely make frost coverage
relatively limited. Still, the need for a frost advisory will need
to be watched closely this evening should coverage expand and
offshore flow become stronger.

Clear and slightly warmer conditions will persist Saturday,
especially if offshore flow continues through the day. Winds quickly
turning onshore ahead of a weak trough passage to the north will most
likely promote a coastal marine layer to form early Sunday morning.
The marine layer lifting through the day may allow for light rain
and drizzle just along the immediate coast Sunday afternoon and
evening. Rain chances are greatest in Crescent City where there is a
25% chance of wetting rain (> 0.1 inches) and a 90% chance of at
least light drizzle. Chances drop by Humboldt  Bay where there is
only a 20% chance of even light drizzle.

Clearer skies and offshore flow will quickly reassert themselves
early next week with another 50% chance of light frost in the
interior by Monday morning. 70% of ensemble members continue to show
a cold, cutoff low pressure system impacting the area mid to late
next week, though potential timing is very uncertain. At least some
rain is very likely, but the range is large (most likely 0.5 to 2.0
inches) because many models focus the system north. Should rain
occur, it will focus on the North Coast. NBM shows snow levels of
3000 to 4500 feet on the back end of the system, which could bring
some of the lowest elevation (albeit very light) snow of the season
so far. There is little ensemble support (less than 20% over 45 mph)
of any impactful winds with the system. /JHW


&&

.AVIATION...(18Z TAFs)...Northerly winds have filled in as of
20z with VFR conditions prevailing at the coastal terminals. A
reduction in visibility from haze at KCEC and KACV, will bring
periods of MVFR. There is a low probability (17-22%)of ceilings
lower than 6500ft for the coastal terminals. With light winds
expected tonight, there could be some ground fog development but dry
easterly flow could limit development overnight into Saturday early
morning. Light northerly winds through the TAF period is expected
for KUKI, likely lasting into Saturday morning with prevailing VFR
categories. /EYS


&&

.MARINE...Northerly winds continue through the evening and fill
in to all area waters into Saturday. A westerly swell with wave
heights of 10-12ft at 16-17 seconds will occupy area waters for the
next few days, slightly diminishing by Sunday to 10ft at 15 seconds
or so. Wind waves with a square profile around 8-10ft at 8-9 seconds
will also be in effect and combine to make seas 11-14ft, with the
larger waves in the outer waters 10 - 60nm. Northerly winds 15-20kt
this weekend will ease by Sunday night 10-15kt but return Monday at
15-20kt. Milder conditions are forecast to return Tuesday evening.
/EYS


&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
None.
NORTHWEST CALIFORNIA COASTAL WATERS...
     Small Craft Advisory until 7 AM PST Sunday for PZZ450-470.

     Small Craft Advisory until 3 PM PST Sunday for PZZ455-475.

&&

$$

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