850
FXUS66 KEKA 192220
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
320 PM PDT Sat Apr 19 2025

.SYNOPSIS...Interior high temperatures are forecast to remain slightly
above average through Tuesday of next week. Overnight minimum temperatures
will remain chilly in some of the colder valleys, especially in Trinity
County. Strong northerly winds over the coastal waters will keep coastal
areas much cooler and occasionally windy through next week Tuesday.

&&

.DISCUSSION...Stout surface high pressure anchored west of 140W and
north of 40N coupled with a thermal trough over the interior will
maintain a brisk northerly wind regime for coastal areas through
at least Tuesday of next week. Northerly winds thus far have been
gusting to 34kt (near 40 mph) at CEC ASOS. Elsewhere coastal winds
have not been as strong, gusts generally around 15 to 25 mph. ECMWF
ensemble continues to indicate northerly winds a tad bit stronger
on Sunday, followed by continued windy northerlies Mon and Tue.

Northerlies have disrupted the persistent stratus in lee of Cape
Mendo (SW Humboldt around Shelter Cove and lost Coast). The north
wind surge has also resulted in a replenishment of coastal stratus
from about Ft Bragg southward. A small scale eddy that spun up
north of Bodega Bay has been dissipating this afternoon. New eddies
may develop in the lee of Cape Mendo later tonight once the
nearshore northerlies decouple. Northerlies have also packed low
clouds into the Eureka area and Eel delta. Otherwise, skies
cleared in the wake of the front. High resolution models as well
as BUFKIT profiles indicate deep humid layer persisting on Sunday
and Monday, so suspect there will be some low clouds each day and
night around Humboldt Bay into the Eel delta.

Overnight temperatures have been dipping into the mid to upper
30`s in colder valleys of mostly Trinity County the last couple of
nights. Hayfork even dipped down to 33F early this morning for a
few hours. Slightly higher dewpoints in the wake of a cold front
may yield patches of fog or low clouds by early Sunday and keep
overnight min temps higher compared to the last couple of nights.
Min temps from 33-36G have been very localized to colder valleys.
Nearby observations have been much warmer, in the mid 40`s to
lower 50`s. For now will message frost potential in weather story
graphic and social media posts. There is a chance for greater
coverage of frost (min temps <36F) and even freezing low temps
Monday and again Tuesday. NBM has been bit too warm and have
adjusted closer to 1st percentile and legacy statical guidance.

Another shortwave trough in the westerly flow aloft will track
across the area on Sunday. Convective allowing models as well as
coarse deterministic global spectral models keep precip and
convection to the east of the area. A deeper trough will dig down
from the NW by mid week (Wed). Ensemble clusters continue to show
a great deal for variability with this trough and once again will
not adjust NBM precip chances. A few cluster indicate a wetter
scenario which may amount to a few showers over the mountains.

Latest ensemble cluster means were in generally good agreement with
a trough complex approaching NW CAL by end of day 5 (4/24 Thursday)
with eastward progression across our forecast area through day 8
(4/27 Sunday). Finer details are lacking this far out. Details such
as timing and speed of progression, positioning of the cold core
aloft and just the overall evolution of the trough are still up
in the air and uncertain. It is possible for the upper trough or
cold core low to become negatively tilted which will promote more
t-storm development out toward the coast and over the waters.
Southerly surface winds would make this even a better setup for
storms. Now, multiple individual cluster means are considerably
wetter on days 6 and 7 (4/25 Fri->4/26 Sat) vs the grand 100
member ensemble mean. There is also about an equal membership that
are drier too. NBM continues to indicate 30-50% chance for > 0.25in
of precip in 24 hours. Stay tuned. DB

&&

.AVIATION...Clear skies prevail today with strong gusty north winds
along the coast. VFR conditions expected through the afternoon. A
deep marine layer is forecast to return to the Humboldt Bay area
again tonight filling in after midnight. Any stratus that fills in
is expected to mix out quickly tomorrow morning as strong northerly
winds continue tomorrow. Inland at KUKI, VFR conditions are
forecasted through tomorrow morning.

&&

.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 30 kts in both the
outer waters and the inner waters this afternoon. Steep, short
period seas will gradually build alongside the wind.

Winds will only continue to increase on Sunday with high confidence
in gale force conditions throughout the outer waters with gusts in
excess of 35 kts. Winds in the inner waters will experience the
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 Wednesday
morning. /JHW

&&

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

     Small Craft Advisory until 9 AM PDT Tuesday for PZZ455.

     Gale Warning until 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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