Area Forecast Discussion
Issued by NWS Eureka, CA

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196
FXUS66 KEKA 302114 CCA
AFDEKA

AREA FORECAST DISCUSSION...CORRECTED
National Weather Service Eureka CA
214 PM PDT Wed Sep 30 2026

.KEY MESSAGES...

* High pressure builds through the rest of the week, bringing an
  extended dry period for the interior and overcast conditions for
  the North Coast.

* Northwest gusts are expected again Wednesday with gusts up to
  30-45mph for the King Range and other exposed terrain and gusts
  up to 20-25mph for North Coast headlands.

&&

.SYNOPSIS...Upper-level ridging builds over the West Coast this
week. A warming trend is expected for inland areas with coastal
areas being more likely to have morning overcast or foggy
conditions.


&&

.DISCUSSION...The end of the week will be dominated the interactions
of a Pacific high pressure center off the California coastline
and a developing thermal trough in the wake of Hurricane Polo.
This set up will lead to a more "summer-like" pattern as the week
goes on. Inland areas can expect warming through the end of the
week, peaking on Saturday with inland valleys reaching the mid to
high 90s. North Coast areas can expect overcast skies developing
each evening with areas of localized fog and drizzle. These are
likely to scatter out in the afternoons. The Mendocino coastline
is expected to remain relatively clear trough the end of the week
with breezy north winds.

Another expected result of this weather pattern is gusty north
winds along the Nort Coast. Marine waters will remain hazardous
due to short- period waves caused by winds up to 35-40kts in the
windiest spots. Directly along the coastline and in river valleys
close to river mouths for Humboldt and Del Norte Co., expect
breezy afternoons. The King Range will receive the bulk of the
winds with gusts reaching up to 50kts on the exposed ridgetops as
northerlies flow over the E-W orientated topography. Inland
valleys are likely to see gusts up to 15-20mph in the afternoons.

This weather pattern is expected to continue through the rest of
the work week and the weekend into next week. A shortwave
disturbance is likely to flow over the area Sunday, yet minimal
impacts are expected from this features. Only the most extreme
models show any rain, albeit wetting rain >0.10", forming with
this system. The GEFS and EPS ensemble models show the upper
level ridge continuing through next week.


&&

.AVIATION...Marine stratus continues to force LIFR conditions for
the North Coast. Satellite imagery shows an eroding marine layer
from the mountains toward the coast , yet the direct coastline
remains overcast. North winds will continue for ACV while
southerly light winds remain at CEC, yet the forecast suggests
that northerlies will eventually win out as peak heating during
the day. Inland terminals will see terrain driven afternoon gusts
up to 15-20mph and VFR conditions. Winds aloft near the coast
around 2500 ft AGL will remain strong with possible mountain waves
near the King Range and other terrain close to the coast.


&&

.MARINE...Fresh northerlies continue due to the pressure gradient
between offshore high pressure and the interior thermal trough.

* Northern Inner Waters: Northerlies of 10 to 20 kt will generate
  steep short-period seas. A west-northwest swell at 12 to 14
  seconds continues today. A Small Craft Advisory remains in effect
  through Thursday morning.

* Northern Outer Waters: Northerlies of 20 to 25 kt with gusts to
  35 kt (mainly in the lee of Cape Blanco) will build combined
  seas to 10 to 11 ft. A Gale Warning is in effect until Thursday
  morning.

* Southern Inner Waters: Fresh to strong northwest winds of 20 to
  25 kt with gusts of +35kt (mainly in the lee of Cape Mendocino)
  will maintain steep seas. Steep waves are likely to propagate
  into the coastal waters. A Small Craft Advisory remains in
  effect through Thursday morning.

* Southern Outer Waters: Gale force conditions develop in the lee
  of Cape Mendocino, where northerly winds of 25 to 30 kt with
  gusts up to 40 kt will yield steep, hazardous combined seas of
  11 to 12 ft. A Gale Warning remains in effect through Thursday
  morning.


&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
None.
NORTHWEST CALIFORNIA COASTAL WATERS...
     Small Craft Advisory until 9 AM PDT Thursday for PZZ450-455.

     Gale Warning until 9 AM PDT Thursday for PZZ470-475.

&&

$$

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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