Nicolaus, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

514
FXUS66 KEKA 132227
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
227 PM PST Tue Jan 13 2026

.SYNOPSIS...High pressure continues over NW California resulting
in dry weather and warmer daytime temperatures this week. Overnight
and early morning temperatures will remain chilly. Nocturnal
valley fog will form each night in the river valleys, especially
in Trinity, Humboldt and northern Mendocino Counties.

&&

.DISCUSSION...An upper level ridge has situated itself over the West
Coast leading to large scale subsidence and adiabatic warming.
Offshore wind flow has also kept coastal stratus patchy at best
and confined to the coastal waters. Clear skies and longwave
cooling through the night will continue to result in cold mornings
in the valleys and for some coastal areas where strong nocturnal
inversions develop. Higher elevations in and above the thermal
belt as well as south facing aspects will likely respond to the
warming aloft. Wide valleys in southern Mendocino and Lake with
better sun exposures will also be more likely to warm up into the
lower to mid 70`s Wednesday through Friday. Gustier easterly and
northeasterly winds are probable over the exposed ridges and
higher terrain tonight and Wednesday. These offshore breezes will
likely continue into Thursday and Friday.

Another area of concern is coastal stratus and fog. Satellite
showed areas of stratus and possible fog lingering over the coastal
waters this afternoon. This field of stratus and potential fog
has been touching the shoreline this afternoon. Most areas have
been basking in sunshine. Fog was locally dense this morning
around Humboldt Bay per observations at WFO Eureka. Fog could
once again become dense this evening and into early Wednesday
morning, especially around Humboldt Bay. Not confident on the
coverage and if fog will make it into the Eel delta.

With a stronger nocturnal inversion in narrow east-west oriented
valleys sheltered from sunlight, the air has become stagnant.
With stagnate air, there is an increased risk of smoke and other
pollutants remaining in valleys for multiple days leading to the
potential for reduced air quality. Some AQI sensors for PM2.5 are
already in the moderate range with spikes up into unhealthy for
sensitive groups. Be sure to monitor air quality for your specific
location by visiting https://www.airnow.gov

Upper ridging aloft and offshore wind flow will ensure a continuation
of dry weather for the remainder of the week into the weekend. So
far there are not any strong signals from the global ensembles
and deterministic solutions for any significant rain. Some drizzle
could be squeezed out from a stratus push early or mid next week
as a transient front clips the area. Probabilistic guidance is
not very high at this point (no more than a 10% chance) even for
a few hundredths. Mostly dry and stable weather is forecast for
the next 7 days.

&&

.AVIATION...(18Z TAFs)...Satellite view late this morning shows
stratus and fog in many interior valleys along with stratus right
off the coast. Coastal stratus will likely make a push towards the
coastal terminals this evening and overnight, but weak offshore flow
could delay or prevent stratus from forming, much like this morning.
Should stratus develop, the shallow inversion will likely produce
LIFR to IFR conditions for both ceilings and visibilities. Interior
valleys will likely see fog and stratus again tonight. UKI has
around a 30% chance of seeing stratus develop. JB

&&

.MARINE...The sea state continues to be dominated by a mid period
northwesterly swell. Northerly winds start to increase this
afternoon and evening as the pressure gradient tightens. North winds
continue to increase into Wednesday, with isolated gale force gusts
possible in the immediate lee of Cape Mendocino and around 50
nautical miles from Point St. George. Steep wind waves of up to 12
feet will be associated with these winds. Winds nearshore are
expected to be much lighter, but there is a chance for steep waves
to propagate nearshore Wednesday night. Winds begin to ease
Wednesday night and seas subside Thursday into Friday. JB

&&

.BEACH HAZARDS...A Beach Hazards Statement has been issued between
10 AM Wednesday and midnight Thursday. A long period westerly swell
fills in Wednesday afternoon, bringing a low to moderate risk for
sneaker waves to the coast. Avoid steep beaches and jetties and
remember to never turn your back on the ocean! JB

&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
None.
NORTHWEST CALIFORNIA COASTAL WATERS...
     Small Craft Advisory from 4 AM Wednesday to 10 PM PST
     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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For forecast zone information
see the forecast zone map online:
https://www.weather.gov/images/eka/zonemap.png