278
FXUS66 KEKA 140702
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
1202 AM PDT Tue Oct 14 2025

.SYNOPSIS...The area of low pressure continues to push southward
pulling the precipitation towards the southern area of the CWA.
There will be chances for interior frost this week, especially if
cloud coverage clears with calm winds. Temperatures will warm
later this week as high pressure builds back in.


&&

.DISCUSSION...As an upper level cut off low moves southward through
the night, rainfall can be expected over Mendocino and Lake counties
through the morning. There will also be extended chances for showers
through Trinity County as the low stalls over Central CA before
weakening and migrating east. Convective allowing models (CAMs)
resolved some stronger terrain enhanced showers this afternoon over
the eastern portions of the far interior mountains. Some model
soundings shows barely enough instability in addition to with an
equilibrium level at -30C, possibly leading to for a couple
thunderstorms over the high terrain from Southeast Trinity south
into far interior Lake County briefly this afternoon. However, more
than likely these will materialize as rainshowers.

Overnight temperatures will be lower this week as the cold frontal
passage advected cooler air into the area. The synoptic circulation
will force offshore breezes, possibly attempting to dry the valleys.
Some areas of frost may develop, but coverage looks limited at this
time given the lingering unsettled weather which will inhibit frost
formation. Frost chances for tonight will have to be reexamined as
the day goes on to see how the rainshowers situation has changed
the chances for frost.

High pressure will expand in from the west through the latter
portion of the week and into the weekend. Above normal temperatures
are forecast over this period with strong chances (70-80%) for the
warmer interior valleys to reach or exceed 80F. Rain chances
increase again through the latter half of the weekend as
deterministic and cluster analysis shows the potential for another
frontal passage.
JJW/Schmiegel


&&

.AVIATION...(06z TAFs)...The upper level low pressure system will
continue to move south and east over Northwest California. Because
of the track of the system, cloud cover will remain over Mendocino,
Trinity, and Lake counties while clouds continue to pull away from
coastal Humboldt and Del Norte counties. As a result, most coastal
terminals are expected to remain VFR through this TAF period, while
interior terminals more south (KUKI) or more east will have
borderline MVFR ceilings into Tuesday morning. There is potential
for isolated showers into Tuesday morning for southern Mendocino
County,and also southern and eastern Lake County. /JLW


&&

.MARINE...Winds will remain northerly across the waters and
slightly diminish early Tuesday morning. Some isolated showers and a
few thunderstorms are possible in the extreme southern waters as the
upper level low continues to move off to the SE. Waves are dominated
by a northwest swell that have built to around 10 to 11 feet at 10
seconds or so. This is expected to start diminishing early Tuesday.
In general have gone slightly over the model guidance with this wave
coming in higher than expected. In addition to this swell, short
period wind driven waves are expected to peak around 5 to 7 feet.

Tuesday northerly winds remain stronger beyond 20 NM and start to
become southerly close to the coast as the upper level trough pulls
out of the area. These remain lighter on Wednesday before
strengthening again on Thursday and Friday. Saturday, winds are
expected to start diminishing again ahead of the next weather system
on Sunday. Tuesday, a long period swell starts to build in.
Initially it is expected to be around 3 feet at 16 seconds and that
is also expected to be it`s peak. Otherwise waves are expected to be
steep and wind driven. MKK


&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
None.
NORTHWEST CALIFORNIA COASTAL WATERS...
     Small Craft Advisory until 5 AM PDT early this morning for
     PZZ450.

     Small Craft Advisory until 3 PM PDT this afternoon for
     PZZ455-470-475.

&&

$$

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