Glenhaven, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

509
FXUS66 KEKA 132152
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
252 PM PDT Sun Apr 13 2025

.SYNOPSIS...Warm and calm weather will continue through Monday with
cooler and gustier conditions through the rest of the week. There
remains little to no chance of wetting rain through the end of the
week.


&&

.DISCUSSION...

KEY MESSAGES:
-Warm, calm, and dry conditions persist through Monday with
potential for interior highs over 85 and coastal highs near 70.

-Cooler though still Sunny conditions return for the interior
midweek with potential for isolated Thunderstorms over high terrain
Tuesday and especially Wednesday afternoon.

-Cool and gusty onshore winds return for the coast Wednesday and
Thursday.



WEATHER PATTERN OVERVIEW: Weak and transient upper level ridging has
spread over the area today. Compared to the last couple days, high
pressure has gradually weakened winds and has allowed interior
temperatures to warm into the low 80s. Low pressure forming off the
central coast has helped gradually turn gentle wind offshore,
greatly drying out conditions. High pressure will continue to build
Monday with interior valleys in the mid 80s. Offshore flow has a
slight chance (20%) of allowing temperatures as high as 70 along the
coast.

High pressure will gradually weaken by mid next week as a shallow
shortwave dips along shore. The largest impacts of this patterns
will be temperatures cooling back into the upper 60s for the
interiors with a return of more gusty north wind along shore, though
there is little chance (10%) of gusts of similar strength to the
past couple of days. Resurgent moisture and onshore flow will likely
help rebuild the marine layer Tuesday morning. Additionally, some
moisture pulling from the south combined with more unstable air
aloft and strong solar heating may help generate diurnal afternoon
thunderstorms. The greatest chance (20%) of showers is over the
Yolla Bollys and Trinity Alps late Wednesday afternoon.

There is some forecast uncertainty by the end of the week as a
cutoff low is forecast to travel south along shore, but essentially
no model ensemble members show any measurable precipitation along
the low.



FORECAST CONFIDENCE AND DEVIATIONS: Forecast confidence is high at
least through early next week with not real hazardous scenarios of
note.

As is normal, the greatest forecast variability in the short term is
related to the chance of a marine layer forming alongshore tonight
into Monday. The greatest chances (30%) will be around Humboldt Bay
with any layer most likely to be very shallow. Related to this
chance, Monday has the greatest uncertainty in coastal high
temperatures. Though most models show highs in the mid 60s, about
20% show the potential for highs reaching 70 if marine air burns off
quickly and offshore flow is strong enough.

Beyond that, the greatest uncertainty will be for interior
thunderstorms Tuesday and Thursday and near shore winds around
Wednesday and Thursday. For the Thunderstorms, EFI shows a weak
signal for elevated CAPE, mostly around the Yolla Bollys. There is
significant uncertainty weather or not moisture will be sufficient
to form storms, SREF currently shows 30% chance of isolated storms
though NBM is much lower around 10%. The overall ensemble moisture
spread remains high, but the potential is certainly there as soon as
Tuesday afternoon with the greatest chances Wednesday afternoon over
high terrain.

For near shore wind, there is a consistent signal of gustier north
wind returning near shore, but their strength remains very variable
with about 40% of ensemble members showing gusts below 15 mph but a
group of about 30% showing gusts near 30 mph. The overall
distribution is roughly bimodal for wind. Otherwise although the
exact detail of temperature and wind have high uncertainty by late
in the week, essentially no models indicate wetting precipitation.
/JHW


&&

.AVIATION...Conditions at all the terminals are VFR this afternoon.
Offshore winds have cleared skies across Northwestern California.
Models are showing a shallow marine layer developing tonight, which
does bring the potential for IFR/LIFR fog/stratus impacts to the
coastal terminals. NBM is showing around a 40% and a 70% chance for
IFR ceilings at ACV and CEC, respectively, early Monday morning.
Weak offshore flow aloft is also forecast tonight, which could keep
all stratus impacts offshore. Regardless, any stratus that does
develop will likely lift and scatter out by the late morning. UKI is
forecast to remain VFR for the next 24 hours. JB


&&

.MARINE...Winds and seas have gradually eased today and will
continue to ease into Monday. Strong northerly breezes and steep
seas are still forecast in the outer waters into tonight, with
lighter winds expected nearshore. Seas are still steep nearshore
early this afternoon north of Cape Mendocino, hovering around 6-7 ft
at 6 seconds. Seas are forecast to ease by the late afternoon and
evening. Nearshore winds and seas are forecast to be mild for much
of Monday.

Northerly winds increase again Monday evening into Tuesday, with
strong breezes to gale force gusts possible in the outer waters,
especially north of Cape Mendocino. Seas will respond with 13-15 ft
significant wave heights in the outer waters. Lighter winds are
forecast nearshore, but conditions could still be hazardous to small
crafts with steep seas of 7-10 ft and gusts of 20-25 kts by
Wednesday. JB


&&

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

     Small Craft Advisory until 3 PM PDT this afternoon for
     PZZ455.

     Small Craft Advisory until 9 AM PDT Tuesday for PZZ470-475.

     Gale Watch from Tuesday morning through late Tuesday night
     for PZZ470.

&&

$$

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