481
FXUS66 KEKA 290858
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
1258 AM PST Sat Nov 29 2025

.SYNOPSIS...A mid period westerly swell will bring a moderate
risk for hazardous beach conditions Saturday afternoon. A much
more energetic westerly swell group will bring a high risk for
sneaker waves Monday through Tuesday next week. Otherwise, dry
and seasonably cool weather is forecast for the next 7 days.


&&

.KEY MESSAGE...

* Dry and seasonably cool weather expected through the next
  7-days, with a mix of sunshine and clouds.

* A Moderate Risk of sneaker waves risk is expected along the
  Northwest California beaches this afternoon and early evening.

* Sneaker Waves risk increases to High on Monday and continue
  through Tuesday.

* Blustery north and east-northeast winds over the ridges Tuesday
  night into Wednesday.


&&

.DISCUSSION...Latest GOES-West satellite imagery depicts stratocumulus
continuing to stream eastward across the area, while coastal low
clouds persist overnight. Despite the high-level cloud cover, chilly
overnight temperatures in the mid to low 30s have been observed
in Trinity, portions of interior Mendocino and Lake counties.
Southern Lake County have not seen a widespread killing freeze yet
this Fall. A Frost Advisory is now in effect until 9 AM this
morning for southern Lake County. Dry weather and seasonably
temperatures continue today, with a mix of sunshine and clouds.

A semi-stationay upper-level ridge over the northeastern Pacific
will act as a blocking pattern through the next 7-days, forcing
any "inside slider" weather disturbance to track southward from
the Pacific NW. A dry shortwave trough will swoop down across the
Pacific NW into the Great Basin over the weekend and serve to re-
establish an offshore wind regime across the area by Sunday. Breezy
northerly winds will develop along the coastal headlands and
exposed ridges by Sunday. Offshore winds are expected to develop
over the higher terrain across the interior Sunday evening and
increase into Monday morning, with the strongest winds anticipated
over the eastern portion of Lake County where gusts up to 25-35
mph are possible. Frost and freezing morning temperatures will
also be possible. Average low temperatures for this time of year
are in the low to mid 30s in the interior valleys and agricultural
interests have ended. Frost and freezing morning temperatures
could kill tender plants left outside in the cold.

A third shortwave trough may (18% chance) generate a few fleeting
light showers or sprinkles for Del Norte and mountains of Trinity
Monday-Tuesday. This shorter wavelength trough will carve out a
larger scale trough that will head southward over central and
southern Cal by Wednesday. Another possible outcome is for the
trough to dig much farther east over the Great Basin with a
massive ridge aloft taking hold over the forecast area by
Wednesday. Blustery N and E-NE winds will develop Tuesday night-
Wednesday for the higher terrain and perhaps Lake County. E-NE
wind gusts to 35-45 mph will be possible over the ridges. The air
mass is not forecast to be exceptionally cold next week either.
With dew points in the 20s, calm winds in the valleys and clear
skies overnight, frost and freezing temperatures will once again
crop up for areas that have not had a so called killing freeze
yet. Fog and low clouds will no doubt (a 100% chance) be a nightly
occurrence in the interior river valleys, especially Humboldt and
Trinity. Cold weather advisories for wind chill may also be
necessary for wind gusts around 10-15 mph. Our long stretch of dry
cool weather may finally come to an end late next week. All
global ensemble systems indicate increasing probabilities for 0.10
inches of precip in 24hr over multiple days from Dec 6 to Dec 8.


&&

.AVIATION...06z TAFs...Ceilings have gradually dropped through the
evening, with mostly MVFR ceilings along the coast around midnight.
There is high model disagreement on the exact evolution of conditions
into Saturday morning. Most models show at least borderline IFR to
MVFR ceilings through the early morning, especially around Humboldt
Bay, with IFR to LIFR fog for many interior valleys including Ukiah.

 Interior conditions will most likely quickly clear after sunrise.
Most ensemble members show lifting to MVFR or VFR along the coast
during the day Saturday, but about 30% of models show MVFR ceilings
more persistent through the day. A weak trough passing to the north
may help lift ceilings Saturday night, but will also promote onshore
flow conducive to marine layer formation. With those two competing
forces, ensembles continue to show uncertain and mixed conditions,
but with little potential for widespread, disruptive LIFR
conditions. /JHW


&&

.MARINE...Weak to moderate northerly winds have built in all across
the waters. Northerly winds will continue to increase in the outer
waters with near gale force gusts in the southern outer waters
Sunday gradually spreading northwards. North winds and steep short
period seas will stay restricted to the outer waters and will
briefly weaken again around Monday. There is strong agreement,
however, that north winds will push back closer to shore around mid
next week with periods of strong gale force gusts.

Aside from the winds, a minor mid period westerly swell will build
up to around 8 feet late Saturday into Sunday, but this swell will
quickly decay. Another, much longer period swell will build around
Monday into Tuesday up to around 12 feet. Neither swell will be
particularly steep but will dominate the inner water sea state where
short period seas are calm. /JHW


&&

.BEACH HAZARDS...A series of mid period westerly swells will
continue to impact the waters through the weekend. The next swell
will build up to 8 feet at 14 seconds beginning Saturday afternoon
into Sunday. With mostly calm short period seas, the forerunners of
this swell especially will pose a moderate sneaker wave risk
Saturday evening with unexpected and inconsistent surf on area
beaches Saturday afternoon.

A second, stronger sneaker wave risk is possible as longer period
swell builds Monday into Tuesday. The very long period of this swell
up to 22 seconds will make waves particularly deceiving with the
swell likely to build in rapidly with little warning. Short period
seas building closer to shore will lessen the overall risk by around
mid week. /JHW


&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
     Beach Hazards Statement Saturday afternoon for CAZ101-103.

     Beach Hazards Statement from Saturday afternoon through
     Saturday evening for CAZ104.

     Beach Hazards Statement from Saturday afternoon through
     Saturday evening for CAZ109.

     Frost Advisory until 9 AM PST Saturday for CAZ115.

NORTHWEST CALIFORNIA COASTAL WATERS...
     Small Craft Advisory from 11 AM to 11 PM PST Sunday for
     PZZ455-470.

     Small Craft Advisory from 11 PM Saturday to 5 AM PST Monday
     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