900
FXUS66 KEKA 221218
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
518 AM PDT Tue Apr 22 2025

.SYNOPSIS...Cooler overnight temperatures with pleasant daytime
highs will continue for the next few days. Strong northerly winds
will ramp up in the afternoons near the coast, starting to weaken by
Wednesday. Unsettled weather with a chance of rain is forecast
Thursday afternoon through Saturday.


&&

.DISCUSSION...The approach of a mid level short wave trough will
enhance instability as the max vortex of this feature will focus on
coastal Del Norte and Humboldt counties. Tightening pressure
gradients will encourage winds to gusts offshore up to 50mph and at
a lesser degree on the coast, up to 33mph by the early evening
hours. High temperatures today will be near the high to mid 50`s
approaching 60 near coast while inner valley temperatures could
reach mid 70`s at Willow Creek and Hoopa. Big Bar will likely reach
the highest temps at 80 or so and Weaverville a few degrees below
that. Wednesday will be similar in temperature scheme before
temperatures come down Thursday by several degrees.

Thursday the pattern starts to shift as an upper level low
approaches the coast. This will likely bring more widespread coastal
stratus which may not clear out in the afternoon. Drizzle will be
possible especially if there happens to be a weak wave moving around
the base of the low. This also has the potential to bring a slight
chance of thunderstorms to the interior mountains in the afternoon.
The GFS is showing around 100 to 200 j/kg of surface CAPE while the
NAM is showing more like 300 to 500 j/kg. The NBM is showing a 15 to
20 percent probability over Trinity county. Soundings are showing
inverted V patterns in Trinity county for Wednesday and Thursday.
Lapse rates have slightly improved in the mid levels to 8.1 - 8.4
C/km for both days.

Friday there is a better chance for a rain showers across much of
the area. The higher amounts are expected to be in northern Humboldt
and Del Norte counties, but at least some rain likely to make it
down to Lake county. The newer NBM model runs have been diminishing
the rainfall int he forecast and now the highest amount are less
than an inch in the Del norte mountains with less than a quarter
inch expected anywhere besides the mountains of Humboldt and Del
Norte counties.

Skies are expected to clear out Saturday afternoon as showers come
to an end. This will allow temperatures to drop overnight.
Any areas that don`t see fog develop will likely see temperatures
drop into the 30s with frost in the colder spots. /MKK /EYS



&&

.AVIATION...Coastal stratus is filling in this morning and spreading
through the Eel river valley as well as northward towards KCEC,
which is showing IFR conditions as of 12z with overcast skies and
ceilings around 600-700ft with reduced visibility. KACV has faired a
bit better with MVFR conditions and 1000-1200ft ceilings. Both
coastal terminals will improve once the northerly winds build and
gust up, scouring out the low cloud cover. Expect gusty winds to
last through the day and into the evening at KCEC while KACV will be
a bit more sporadic in regards to winds as it is sheltered a bit
more than KCEC. MVFR for both coastal terminals once the northerlies
set in. Prevailing MVFR conditions are expected at KUKI with light
northerlies once the evening hours commence. /EYS


&&

.MARINE...Gale force northerly winds continue into Wednesday for
outer waters, and to some extend part of inner waters as well,
especially south of Cape Mendocino. Confidence has increased that
wind speeds will remain strong enough into Wednesday to continue
the current gale warnings/small craft advisories through 3 PM
Wednesday. NBM mean 24 hour max wind gusts of 45-47 KTS still
encompass at least 50% of both northern and outer waters. Still
expecting steep seas for outer waters and to a least some extent,
inner waters through at least Thursday. Potential for hazardous
seas following gale warnings is still rather high through Thursday
morning for outer waters and at least small craft advisory worthy
for inner waters. /MH


&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
     Frost Advisory until 9 AM PDT this morning for CAZ107-108.

NORTHWEST CALIFORNIA COASTAL WATERS...
     Small Craft Advisory until 3 PM PDT Wednesday for PZZ450-
     455.

     Gale Warning until 3 PM PDT Wednesday for PZZ470-475.

&&

$$

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https://www.weather.gov/images/eka/zonemap.png