Area Forecast Discussion
Issued by NWS Eureka, CA

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162
FXUS66 KEKA 090804
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
1204 AM PST Tue Dec 9 2025

.SYNOPSIS...Areas of dense fog and low chances for coastal drizzle
for portions of the North Coast through mid week. Generally dry
weather and a warming trend are expected to prevail across NW CA
this week, with record warmth likely for the interior.


&&

.DISCUSSION...Pocket of fog and overcast skies are expected along
the coast. Fog visibilities are being observed along the North Coast
early this morning. Light drizzles to the occasional light shower
can be expected to continue along the North Coast, mainly in Del
Norte today. Latest guidance only yields trace amounts of measurable
rainfall, but persistent light drizzle may lead to a few hundredths
accumulating along portions of the North Coast. It will remain dry
elsewhere with increasing high temperatures.

The persistent ridge of high pressure southwest of the region
responsible for blocking Pacific storm systems will strengthen and
nose eastward through the workweek. Significant warming will occur
as a result. The current forecast yields interior high temperatures
reaching 10-20F above climatological norms midweek through the
weekend. NBM shows a high probability (70 to 80%) for the warmer
interior valleys to exceed 70 F Thursday and especially Friday (80
to 90%). When looking at NBM probabilities for exceeding 75F, the
Ukiah area shows probabilities of 50% for Thursday and Friday. This
would likely break the high temperature record of 72F from 1958 for
Ukiah on Friday if the forecast holds.

Ensembles and clusters are hinting at the weaken of the stubborn
ridge through the weekend. Precipitation chances start to increase
through the latter portion of the weekend. However, any meaningful
breakdown of the ridge or zonal flow may not occur into early next
week, leading to a further increase of rain chances. JJW/DS


&&

.AVIATION...(06Z TAFs)...The set up for fog could bring or prolong
LIFR conditions through the TAF period and well into Tuesday
morning for the coastal terminals. KCEC has been under a persistent
LIFR regime since 21z. KACV has faired a bit better with
inconsistent improved periods of MVFR yet dominated by IFR mostly.
Subsidence is compacting and stratifying layers of clouds near the
ground and up to 1000ft with most ceilings at KCEC around 300ft.
Conditions are expected to lift a bit as fronts approach Tuesday and
possibly overnight into Tuesday morning. Light drizzle could be a
hindrance to visibility along with the fog with calm winds.


&&

.MARINE...Generally light winds are forecast through Tuesday
morning, with south winds forecast north of Cape Mendocino and west-
northwest winds forecast south of the Cape. Another mid-period
northwest swell will fill in this afternoon and evening, peaking at
7-9 ft at 13 seconds overnight into Tuesday. Combined seas may
briefly exceed 10 ft in some areas. Northerly winds are also likely
to trend northward Tuesday and Wednesday. Northerly wind gusts of 15-
25 kts are possible south of Cape Mendocino Tuesday and Wednesday
afternoons and steep wind waves of 5-7 ft are possible. Additional
mid-period northwest swells will continue to fill in through the
week, keeping seas elevated. JB

&&

.BEACH HAZARDS...An increased threat of sneaker waves is expected
for the Del Norte, Humboldt, and Mendocino coastlines this Thursday.
A mid-period westerly swell generated by a storm currently located
near 45N,160W will enter the coastal waters early Thursday
morning. A lack of local wind waves will allow this swell to
dominate the sea state over an existing swell, creating beach
conditions that could look deceivingly calm. Forecast confidence
continues to grow as the swell passes NOAA/NDBC buoys Wednesday
morning. Remember to never turn your back to the ocean, and to
avoid steep beaches, jetties, outcroppings, and rocks during these
events. DS


&&

.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