214
FXUS66 KEKA 041945
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
1245 PM PDT Sat Oct 4 2025

.SYNOPSIS...Drier and warmer weather is forecast for the next
several days as a ridge of high pressure builds over the West Coast.
The next chance for rain may be late next week as another trough
approaches the region.


&&

.DISCUSSION...Ridging aloft is beginning to fill in behind the
persistent upper level trough from last week. The ridge will be
characterized by drier air, giving way to calmer weather through the
weekend into next week. A positively tilted shortwave disturbance
is expected to form off the coast of central CA Sunday night.
This feature is expected to force offshore winds leading to warmer
temperatures aloft and along the North Coast. Current model
guidance even shows temperatures in Crescent City, Humboldt Bay,
and Fort Bragg reaching over 70F, depending on how strong the
offshore winds are and an remnant cloud coverage. But for right
now, it looks like very pleasant weather early this week for NW
California.

The calmer weather will not last long however as an upper level, cut-
off low is expected to find its way into the NE Pacific Ocean. The
operational runs of the GFS and ECMWF are both predicting this low
to be present off the PacNW coast around the 9th or 10th. Ensemble
cluster analysis shows confidence in this low materializing (89%),
yet the trajectory of the system is still fairly uncertain at this
point. Regardless of where is cut-off low wanders, expect and
increase in rain chances late this coming work week. NBM data shows
about a 50% probability for widespread wetting rain (>=0.1") for NW
California with higher chances in Del Norte and northern Humboldt
counties. If the cut-off low solution develops, the upper levels may
be quite cold resulting in steep lapse rates and the potential for
thunderstorms. It is important to remember that this system is 6-7
days out, more updates to come through the weekend and early this
coming week.


&&

.AVIATION...18Z TAFs...VFR conditions observed midday Saturday. A
band of marine stratus lurks over the waters off the Humboldt coast.
High resolution guidance is mixed whether this this stays just off
of the ACV terminal or brushes over it. TEMPO MVFR to IFR ceilings
are certainly possible this afternoon for ACV. This will be the
pattern overnight, with no solid agreement of the duration or
coverage of coastal stratus. This is mainly due to the light, drying
offshore winds that will develop.

Other than the possible afternoon/evening tempo MVFR to IFR CIGs at
ACV, probabilities are on the low to moderate side for additional
occurrences (40%). There are higher chances (75%) for IFR ceilings
up to Eel River delta through the Fortuna terminal. Clearing
will quickly occur by 18Z or sooner.

VFR CIGS are expected elsewhere with the dry offshore flow. Fort
Bragg has a 30% shot at MVFR ceilings for Sunday morning after 12Z,
with clearing expected quickly by 18Z. JJW


&&

.MARINE...Northerly winds continue to strengthen Saturday. Gale
conditions are ongoing in the southern waters around and south of
Cape Mendocino. Northerly winds will further strengthen Saturday
night through Sunday. This will spread gale conditions into the
norther out waters starting early Sunday morning. Steep, wind driven
seas of 7-9 ft will remain in the waters into Monday. Propagation of
steep seas of 7 ft will be likely into the northern inner zone 450
periodically this afternoon through Sunday night. This will create
some periods of Small Craft Advisory conditions, and a Small Craft
Advisory has been issued for this zone. A weak surface low will
begin to develop over the coastal waters Monday as dry offshore
winds form inland. This will clear out the marine layer clouds and
greatly ease winds down to a light breeze. These conditions will
continue through most of Tuesday with light to gentle breezes from
strengthening northerly winds. The northerly winds are then forecast
to strengthen Tuesday night through Wednesday night. JJW


&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
None.
NORTHWEST CALIFORNIA COASTAL WATERS...
     Small Craft Advisory until 11 AM PDT Sunday for PZZ450.

     Small Craft Advisory until 11 AM PDT Sunday for PZZ455.

     Small Craft Advisory until 3 AM PDT Sunday for PZZ470.

     Gale Warning from 3 AM to 11 AM PDT Sunday for PZZ470.

     Gale Warning until 11 AM PDT Sunday 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