868
FXUS66 KEKA 280712
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
1212 AM PDT Wed Oct 28 2026

.KEY MESSAGES...

* Dry weather is expected this afternoon through Thursday. Rain
  chances return Friday into the weekend.

* Frost and near-freezing temperatures possible for the interior
  valleys and possibly near the coast tonight.

* Minor coastal flooding expected through Thursday at high tide,
  mainly around Humboldt Bay.

&&

.SYNOPSIS...Cool and dry weather is expected through Friday with
additional chances for light rain late Friday and over the weekend.
High tides this week are likely to cause areas of coastal flooding
for areas around Humboldt Bay.


&&

.DISCUSSION...Dry and cool air is gradually building in behind a
passing cold front. Frosty conditions are likely for many interior
valleys by early sunrise. That said, extensive valley fog visible on
satellite may keep conditions warmer than initially forecast, at
least for Humboldt and Trinity counties. Skies are remaining more
clear in Mendocino. Cold nights continue for the coming days with
chances for frost and near-to-below freezing temperatures possible
for the interior valleys, and even close to the coast. High
temperatures also remain chilly in the 50s and low 60s.

The troughing pattern remains in place for the remainder of the
week, but generally remains dry through Friday. Onshore flow will
most likely help a weak, diurnal marine layer reforms, especial.lya
round Humboldt Bay, as soon as Wednesday night. The only exception
to this would be in Del Norte County on Friday, where there is
roughly a 20% of light rain that currently may only amount to a few
hundredths with the bulk of precipitation to the north.

This low off the coast of Oregon moves southward this weekend,
though there is some uncertainty on just how much moisture will
arrive and how far south the low will drop. There is a widespread
near 50% chance of any measurable rain on Saturday for all of NW
California. The chance for wetting rain (over 0.1") is around 20-
30%. There is still a low chance (15%) of over a half inch of
precipitation. This system is a cold system, and snow levels may
drop to around 3000 to 4000 ft. Moisture is limited, but a dusting
of snow in the higher terrain of Trinity County may be possible.

While over a week out at this point, long range ensemble members
show a decently confident signal in a shift towards a more
significant wetter pattern mid to late next week. CPC is
highlighting NW California as having a moderate risk of heavy
precipitation between 11/6 and 11/8 and a slight risk continuing
through 11/10. Exact timing and rain amounts will become clearer
over the coming days. Stay tuned! /JB, JHW


&&

.AVIATION...06Z UPDATE...Dry but still unstable air behind a
passing cold front has allowed for VFR conditions to persist
overnight. High resolution models indicate some scattered MVFR
ceilings are possible (20%) near shore by sunrise. Besides some
IFR fog in interior valleys VFR conditions will persist. A weak
marine layer is more likely to return to the coast Wednesday
night, withs some potential (40% chance) of IFR ceilings. /JHW


&&

.MARINE...Strong northerly winds have build into the southern outer
waters with gusts near gale force. Winds will remain strong and
intermittently push into the inner waters over the next couple of
days. Short period seas will build close to 10 feet by early
Wednesday afternoon. North winds have remained much more moderate in
the northern waters. North winds will persist until early Friday when
they diminish into the weekend. Beyond short period seas, various
minor mid period westerly swell will argument the sea state through
the week. /JHW


&&

.COASTAL FLOODING...Water levels Tuesday 9.26 ft above MLLW at the
North Spit. This brought some minor flooding to low lying areas of
King Salmon and the Arcata bottoms. This was again with an anomaly
of 1.2 to 1.3 feet above astronomical tides. The surge model shows a
similar anomaly on Wednesday, despite winds turning more northerly.
So with an astronomical high tide of 8.06 feet on Wednesday, expect
water levels between 9.1 and 9.3 with similar impacts to Tuesday`s
flooding. A Coastal Flood Advisory has been reissued for Wednesday
afternoon for Humboldt Bay.

Arena Cove is also expected to see water level reach the highest
astronomical tide levels. Waves are only expected to be around 6 to
7 feet at 11 seconds likely limiting the impacts for the Mendocino
coast at this point, yet it will continue to be monitored for any
changes.


&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
     Coastal Flood Advisory from noon today to 3 PM PDT this
     afternoon for CAZ103.

     Frost Advisory until 9 AM PDT this morning for CAZ105-106-
     113-118.

     Freeze Warning until 9 AM PDT this morning for CAZ110-111-
     114.

NORTHWEST CALIFORNIA COASTAL WATERS...
     Coastal Flood Advisory from noon today to 3 PM PDT this
     afternoon for PZZ415.

     Small Craft Advisory until 3 AM PDT Thursday for PZZ455-475.

&&

$$

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