Hidden Valley Lake, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

105
FXUS66 KEKA 191130
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
430 AM PDT Sat Apr 19 2025

.SYNOPSIS...Slightly above average temperatures persist through the
weekend and into early next week. Breezy northerly winds will
develop this afternoon and will increase Sunday. This setup will
persist through mid next week before the pattern breaks down.
The northerly breezes and bouts of lingering daytime stratus will
hold down the coastal temperatures a bit.


&&

.DISCUSSION...Nighttime satellite imagery reveals a blanket of
stratus over the ocean waters and protruding into the coast and
breaching inland. Kneeland Airport is beginning to get coverage
and this implies a deep marine layer, and a glance at the
Mckinleyville profiler confirms the deepened state to be upwards
of 2500 feet. This occurrence can be attributed to falling
pressure heights in advance of a weak shortwave and associated dry
frontal boundary. This depth will keep chances lower for fog
visibility, but the diurnal breakdown to clearing will likely be
hindered. HRRR modeled wind streamlines handle wind eddies fairly
well, and depict one over Humboldt Bay through late morning and
southerly return flow along the coast south of Cape Mendocino
today. These work to feed the stratus back into the coast when the
northerly winds would otherwise peel it away sooner. The
northerly winds are expected to eventually win out going into the
afternoon for Humboldt Bay, but areas south of Cape Mendocino may
see longer lasting coastal cloudcover.


High-resolution models generate a cumulus field this afternoon as
the front passes near peak heating. There will be a brief wave of
fleeting mid level moisture, thus a lone shower or two tied to the
high terrain of Trinity County cannot be ruled out this afternoon.

Northerly winds will increase to breezy levels this afternoon behind
the front and as a thermal trough begins developing. The strongest
wind gusts will be experienced across Del Norte county coastal
headlands. The thermal trough further strengthens Sunday when a
weak shortwave trough clips N CA. There will be a brief pulse of
MUCAPE over portions of eastern Trinity County as the shortwave
passes, and models try to develop very isolated convective
activity in neighboring Shasta County, and if anything develops
that is where is will stay due to very limited low to mid level
moisture over Trinity. Winds behind the trough will maximize
Sunday afternoon and wind gusts of 25 to 35 mph will be likely
along the exposed coastal headlands. Wind gusts of 45 mph are
possible out over the Del Norte Coastal headlands (45% chance from
NBM).

The gusty northerly pattern will persist through much of next week
before the pattern breaks down with the influence of a cold
midlevel trough. Clusters and ensembles are in firm agreement on
general influence of this trough, but differ greatly in the depth
and position of the trough as it moves into N CA or farther north
of the PAC NW. As a result, there are a lot of questions as to
how much precipitation would make it to our forecast area late
next week or through next weekend. Initially, there may be some
convective activity with increasing instability and moisture from
a front on Thursday.

The ensemble members have good agreement on at least some very light
rainfall, and NBM has growing chances for over 0.25 inches of
rainfall in a 24 hour period (33-45%) over next weekend. With snow
levels forecast to be near 5000 feet, there may be some late season
light mountain snowfall. A resulting cooldown will also have to
watched for frost development with the growing season underway.
Currently NBM has moderate probabilities for temperatures lower than
36 for the valleys of interior Mendocino County on next Sunday
morning (4/27). /JJW


&&

.AVIATION...Southerly wind near shore combined with a stronger and
lower marine inversion have helped promote an enhanced marine layer
along shore overnight with IFR ceilings at all coastal terminals.
That said, the shallower marine layer has struggled to extend
inland, allowing for VFR conditions across most inland valleys. 

Building northerly wind will most likely help scour out marine
stratus in more exposed areas of the coast (like KCEC) by late
morning. More protected areas such as near Humboldt Bay will see
ceilings linger longer, but most models (80%) show conditions
clearing to VFR by mid afternoon. Gusty north wind and weakening
high pressure will both lower the probability of a marine layer
reforming Saturday night, but IFR ceilings will remain possible (30%
chance) for at least some of the night. /JHW


&&

.MARINE...After a couple day of calm, fresh northerly breezes have
gradually begun to build in the outer water with gusts over 25 kts
overnight. A passing upper level shortwave will help further enhance
winds through the day today. Gusts will reach over 30 kts in the
outer waters with gusts up to 25 kts pushing into the inner waters
in the afternoon. Steep short period seas will gradually build
alongside the wind.

Winds will only continue to increase on Sunday with solid gale force
conditions throughout the outer waters with gusts in excess of 35
kts. Winds in the inner waters will ebb and flow with strongest winds
pushing near shore in the afternoon. Regardless, steep short period
seas up to 12 feet will fill in all across the waters. ELevated
conditions will be long lived with gale force gusts and steep seas
most likely to persist through at least Tuesday. /JHW


&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
None.
NORTHWEST CALIFORNIA COASTAL WATERS...
     Small Craft Advisory until 9 AM PDT Tuesday for PZZ450.

     Small Craft Advisory from 3 PM this afternoon to 9 AM PDT
     Tuesday for PZZ455.

     Small Craft Advisory until 9 AM PDT this morning for PZZ470.

     Gale Warning from 9 AM this morning to 9 AM PDT Tuesday for
     PZZ470.

     Small Craft Advisory until 3 AM PDT Sunday for PZZ475.

     Gale Warning from 3 AM Sunday to 9 AM PDT Tuesday for
     PZZ475.

&&

$$

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