Frost Advisory 19, NWS Eureka, CA

355 
WWUS76 KEKA 040212
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
712 PM PDT Thu Sep 3 2026

CAZ108-110-111-114-041600-
/O.CON.KEKA.FR.Y.0019.260904T1000Z-260904T1600Z/
Southern Trinity-Northwestern Interior Mendocino-Northeastern
Interior Mendocino-Northern Lake-
Including Peanut, Covelo, Ruth, Gravelly Valley Airport, and Hayfork
712 PM PDT Thu Sep 3 2026

...FROST ADVISORY REMAINS IN EFFECT FROM 3 AM TO 9 AM PDT FRIDAY...

* WHAT...Low temperatures between 34 and 38 degrees may result in
  areas of frost in locations where clear skies develop early Friday
  morning.

* WHERE...Northern Mendocino Interior, Southern Trinity, and Northern
  Lake.

* WHEN...From 3 AM to 9 AM PDT Friday.

* IMPACTS...Frost could harm sensitive outdoor vegetation. Sensitive
  outdoor plants may be killed if left uncovered.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold.

&&

$$

For hazard areas see https://www.weather.gov/wrh/hazards/?wfo=eka

JLW

573 
WWUS76 KEKA 041246
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
546 AM PDT Fri Sep 4 2026

CAZ108-110-111-114-041400-
/O.CAN.KEKA.FR.Y.0019.000000T0000Z-260904T1600Z/
Southern Trinity-Northwestern Interior Mendocino-Northeastern
Interior Mendocino-Northern Lake-
Including Ruth, Peanut, Gravelly Valley Airport, Hayfork, and Covelo
546 AM PDT Fri Sep 4 2026

...FROST ADVISORY IS CANCELLED...

The threat has ended.

$$

For hazard areas see https://www.weather.gov/wrh/hazards/?wfo=eka

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
1242 AM PDT Thu Sep 3 2026

.KEY MESSAGES...

* A general troughing pattern will bring additional light rain
  over the region today and periods of unsettled weather over the
  weekend.

* Overnight temperatures for the interior will turn chilly,
  bringing chances for frost Friday morning and through the
  weekend.

&&

.SYNOPSIS...Winds have sharply subsided into early this morning,
while rainfall turns lighter as the storm system continues east.
Light rainfall chances continue today as a weaker area of low
pressure moves by. Overnight temperatures for the interior will
turn chilly, bringing chances for frost Friday morning and through
the weekend. A general troughing pattern will bring additional
light rain over the region today and periods of unsettled weather
over the weekend.

&&

.DISCUSSION...Winds continue to sharply decline into early this
morning. Rainfall has become light and showery for most of Northwest
California, as well. A second colder and somewhat unstable area of
low pressure will then move by today. This will continue the
chances for showers and perhaps a couple of coastal thunderstorms.

As the environment attempts to clear out through Friday morning,
much cooler overnight lows will develop for the interior. If clouds
do clear out and fog does not develop, areas of frost will be likely
for the interior. There is still some question on the amount of
clearing or even additional light showers, especially with the
numerous troughs forecast through the weekend. These will also bring
a shot for some isolated thunderstorms.

The broad upper low to the north will stall ahead of blocked flow
through the weekend, with weaker shortwave disturbances rotating in.
More at least weak troughing may redevelop behind it. This gives
mixed signals for the extended outlook. There will looks to be some
sort warmup early to mid next week, but if it occurs, it should be
short lived if the troughs continue moving through.

&&

.AVIATION...(06Z TAFs)...Winds and rain continue to diminish
early this morning. Patchy areas of fog may form through the early
morning hours, as well. MVFR to IFR ceilings could persist for
coastal terminals into mid morning, with periods of LIFR. Ceilings
at UKI will likely lower near or below 1500 AGL through the morning
with the light rainfall.

&&

.MARINE...Strong southerly winds have diminished over the coastal
waters. Wind driven seas up to 9 ft will subside below 5 ft early
this morning. A trough from the north will then drive in a steep NW
swell at 7 to 9 ft at 11 seconds today and tomorrow. If the swell
comes in larger near 10 ft then advisory level conditions will be
met. Mariners in small crafts should exercise caution on this day
for this potential threat. Otherwise winds will be light for most of
the waters through Saturday. Then, northerlies will strengthen some
through the weekend, mainly over the southern water south of Cape
Mendocino. The northerlies do not look to fully strengthen again
until early next week. Hurricane Marie will deliver a long period
southerly swell Saturday. Though small, at around 4 ft at 16
seconds, this is a larger than typical swell from this direction.

&&

.BEACH HAZARDS...Hurricane Marie will usher in a long period
southerly swell of 3-4 feet at 16 seconds for south facing beaches
by Saturday. Thus, there could be a risk of sneaker waves,
especially if the swell comes in slightly larger.

Sneaker waves are a unique hazard, with up to 30 minutes between
waves. Large, unexpected waves can sweep across the beach without
warning, sweeping people into the sea from rocks, jetties, and
beaches. These sneaker waves can also move large objects such as
logs, crushing anyone caught underneath. Even ankle to knee deep
water can knock you down and drag you out when a sneaker wave hits.
Pay attention and stay above the high water line and any wet sand to
stay safe. If the ground is wet, waves have surged there recently.
Stay safe and never turn your back on the ocean!

&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
None.
NORTHWEST CALIFORNIA COASTAL WATERS...
None.
&&

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