958
FXUS66 KEKA 270745
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
1245 AM PDT Mon Jul 27 2026

.KEY MESSAGES...

* Moderate risk for sneaker waves along the Lost Coast and Mendocino
  Coast through Wednesday.

* Elevated fire danger through Tuesday for interior areas due to
  breezy afternoon winds.

* Near to slightly below normal interior temperatures expected
  through the middle of next week.

* Coastal stratus likely to form each night and clear each afternoon
  through at least the middle of next week.

* Hot interior temperatures likely to return late next week.



&&

.SYNOPSIS...Near to slightly below normal temperatures are likely
for the interior areas, while near to slightly above normal coastal
temperatures are likely through mid next week. Breezy afternoon
winds elevate fire danger in eastern Trinity, eastern Mendocino, and
Lake counties. Hot interior temperatures return late next week.



&&

.DISCUSSION...Depending on the persistence of stratus into the
afternoons and how early the northwesterly winds start, warmer
coastal temperatures may continue into mid next week. A weak marine
inversion will allow for at least partial, if not full, clearing in
the afternoons. The Mendocino Coast will see breezier afternoon
winds which will support closer to normal temperatures.

The troughing pattern has also brought breezy afternoon winds of 20
to 30 mph in the interior areas, mainly in the higher elevations and
channeled terrain (such as Clear Lake and the Trinity River valley).
Low afternoon relative humidities in Trinity, eastern Mendocino, and
Lake Counties along with these winds brings an elevated fire weather
threat.

There is high confidence in high pressure rebuilding over the area
late next week and next weekend. NBM is showing moderate to high
probabilities for high temperatures in the triple digits for most
interior valleys. Hot temperatures may continue into much of the
following week with over half of ensemble members showing near-
persistent ridging. /JB/JJW



&&

.AVIATION...06Z TAFs.

Key Message:

-IFR to LIFR conditions with a 30% chance for a period of fog
visibilities (highest chances north through CEC) possible at the
coastal terminals, but confidence is overall low (see below). There
is a small (15%) chance of stratus impacting KUKI from the west.
Northwesterly winds will be breezy in Mendocino and Lake Counties
this afternoon and evening. Improvement to VFR is anticipated
through Monday afternoon, but additional stratus will advect down
the coast from the north.

Discussion and Forecast Reasoning:

Ceiling heights began at MVFR levels, modeled to generally lower. One
complication to the ceiling heights and clearing window Monday is a
weak shortwave disturbance progged to advance through in the 13Z to
17Z Monday time span.

Associated mid-level subsidence on the northern periphery of this
feature would quickly compress the marine layer boundary and lead to
more persistent LIFR CIG heights. A slight nudge north of the
shortwave (PVA sector) would allow for some deepening and more
dominant IFR levels. RAP guidance has been shifting north and MOS
guidance has trailed with a trend away from fog greater chances

The shallower levels would give higher confidence for solar heating
to somewhat cleanly break the inversion from north to south,
scattering out KCEC after 18Z and ACV soon after, or as late as 21Z.
A light onshore NW breeze may briefly slosh or advect remnants of
the marine deck back towards the immediate North Coast through the
afternoon. Guidance also drives a more atypical northerly stratus
surge sometime through the afternoon or evening, with currently a
high degree of uncertainty in timing.

The deepened southern portion of the marine layer does bring a small
(15%) chance of stratus impacting KUKI from the west, but sounding
imply the depth will be just short of overcoming the western high
terrain. Northwesterly winds are likely to be breezy in Mendocino
and Lake Counties this afternoon and evening.
/JJW


&&

.MARINE...The sea state is dominated by a small 3 to 5 foot long
period southerly swell and some small mid period westerly and
northerly swells. A second reinforcing long period southerly swell
will arrive Tuesday. Winds will remain very light, only up to 4 to 8
kts Monday north of Cape Mendocino. Northerly winds strengthen 15 to
20 kts, locally up to 25 kts around the cape by Monday afternoon.
Northerlies trend higher in all waters starting Tuesday. Localized
areas of gale conditions will develop in the expansion fan around
Cape Mendocino. /JJW


&&

.FIRE WEATHER...Breezy westerly winds will continue in the
afternoons for interior areas and may be particularly breezy with
gusts of 20 to 30 mph over the ridges and channeled terrain in
eastern Trinity, northeast Mendocino, and Lake Counties. These areas
are forecast to have very low afternoon RHs in the single digits and
teens. Overnight recoveries are expected to be good aside from the
higher elevations of Lake and eastern Trinity County.

Localized critical conditions are possible each afternoon, with the
potential for slightly stronger and more persistent winds Monday
afternoon and evening. This will likely raise RH at least into the
teens or 20s, but so far the marine influence has not had a
significant impact in eastern Lake, eastern Mendocino, and eastern
Trinity Counties. This will need to be watched for the potential of
a Red Flag Warning, should relative humidities remain low into the
evening on Monday while winds remain persistent in the afternoon and
evening.

Closer to the coast, a deep marine layer will bring high RH and
perhaps stratus and/or fog into the river valleys. Afternoon RH
ranges from 70s to 80s at the immediate coast to 20s and 40s in
interior Humboldt, Del Norte, and western Mendocino Counties. /JB



&&

.BEACH HAZARDS...A long period southerly swell with periods up to 20
seconds remains in from tropical systems in the Eastern Pacific. A
second reinforcing long period southerly swell will arrive Tuesday.
These energetic swells will bring a low to moderate risk of sneaker
waves that would be most hazardous on steep, south and southwest
facing beaches along the Lost Coast and Mendocino Coast.

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! /JJW


&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
     Beach Hazards Statement through Wednesday afternoon for
     CAZ104-109.

NORTHWEST CALIFORNIA COASTAL WATERS...
     Small Craft Advisory from 4 AM early this morning to 1 PM
     PDT Tuesday 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