Alton, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

451
FXUS66 KEKA 112109
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
209 PM PDT Sat Apr 11 2026

.SYNOPSIS...More widespread rain and mountain snow is expected
today into Sunday. Thunderstorms with gusty winds and small hail are
possible in Mendocino & Lake this evening and overnight. A chilly
start to the week is expected with near-freezing temperatures
possible in the colder valleys. Additional rain is possible again
Wednesday.


&&

.DISCUSSION...An area of low pressure is quickly approaching
California early this afternoon. Widespread moderate to locally heavy
rain is expected, along with gusty south winds this afternoon.
Generally, the strongest winds will be in southern Humboldt,
Mendocino, and Lake Counties. Gusts could reach 35 to 40 mph, with
locally higher gusts of up to 50 mph possible over ridges and
coastal headlands. A few thunderstorms are possible within the
strongest rain bands. Stratiform rain turns showery this evening and
overnight. The strongest of these showers, especially in Mendocino &
Lake Counties, may have thunder, gusty winds up to 40 to 50 mph, and
small hail. Rainfall totals range from as little as a 0.25" to over
3". The highest rain amounts are concentrated in Mendocino, Lake,
and Trinity Counties where heavier showers are likely to continue
overnight. Snow levels will quickly fall this evening from around
6000 ft to 3500 to 4000 ft. 6 to 8 inches of snow are possible on
Highway 3 at Scott Mountain Pass. Over 3 feet of snow are possible
in the highest elevations in Trinity County.

Sunday, showers continue but begin to taper off as the low begins to
exit the area. A few afternoon thunderstorms may still develop with
lingering moisture and instability, mostly over the interior. Cloud
cover may be too abundant to allow for much warming, which will
limit instability. Temperatures Sunday night to Monday morning will
be chilly, with 30s to low 40s expected for many areas. Some valley
fog may keep temperatures high enough to prevent a widespread freeze
or frost, but some of the coldest valleys could still dip near or
below freezing. Temperatures will remain chilly Monday and Monday
night, with highs in the 50s across the area, and lows in the 30s.
Frost may be possible in more valleys with fewer valleys
experiencing fog. High temperatures begin to rebound Tuesday with
60s likely in most interior valleys. This will be temporary however,
as confidence is increasing on another area of low pressure
approaching the area Wednesday. This system has been trending wetter
and farther south in recent models runs. The NBM is showing around a
70-90% chance for wetting rain (>0.1") for Del Norte and Humboldt
Wednesday, with much smaller chances inland and south into Mendocino
& Lake. The chance for over 1" is low, around 30% in the mountains
of Del Norte, and near zero elsewhere. JB


&&

.AVIATION...(11/18Z TAFs)...SHRA continue moving across the
region as a surface low approaches. Mainly MVFR conditions, dropping
to IFR/LIFR with the heaviest rain is expected to continue through
the period across the TAF sites and other terminals. Chance of
thunderstorms increase across the interior after 20Z. A period of
VCTS in UKI is expected for this afternoon (11/20Z-12/00Z), and
again tonight (12/07Z) through at least Sunday morning (12/18Z).
Expect gusty and erratic winds and possible hail with any TSRA
(thunderstorm). S-SE winds at 5-10 kts increasing to with occasional
higher gusts this afternoon. S-SE winds at 5-10 kts with occasional
higher gusts. However, a rapid and brief increase in south winds is
expected with the frontal boundary pushing onshore mid/late
afternoon, especially for areas south of Cape Mendocino. Expect a
period of gusts between 20-30 kts in UKI. /ZVS


&&

.MARINE...Hazardous marine conditions for small crafts have
developed across the water with a rapid increase of south winds as a
frontal boundary moves through. Fresh to strong south breezes is
already observed over the southern waters this afternoon, and
quickly spreading to portions of the northern waters. A period of
isolated gale force gusts is expected in the southern inner waters
and around Cape Mendocino. The frontal boundary is also leading a
line band of moderate to heavy rain south of Cape Mendocino.

Winds should gradually ease and become gentle to moderate breezes
south of Cape Mendocino tonight, while light and variable over the
northern waters as the surface low passes overhead. Thereafter,
breezy W-NW winds will develop early Sunday. A period of steep seas
around 6-7 feet at 6-7 seconds is expected tonight. A west-nortwest
seas around 5-7 feet at 9-10 seconds and some small swells will
dominated the waters on Sunday.

Monday, northerly winds returns as high pressure starts to build
into the area. This will promote moderate to fresh northerly breezes
across the waters Monday through Tuesday, with the strongest winds
south of Cape Mendocino. Wednesday, a brief wind shift to south is
expected over the northern waters as a frontal system moves through,
followed by strengthening northerly winds Wednesday night through
Friday as the pressure gradient tighten. There is a potential (75-
95% chances) of gale force guts late next week. /ZVS


&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
     Winter Weather Advisory until 11 PM PDT Sunday for CAZ107.

NORTHWEST CALIFORNIA COASTAL WATERS...
     Small Craft Advisory until midnight PDT tonight 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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see the forecast zone map online:
https://www.weather.gov/images/eka/zonemap.png