349
FXUS66 KEKA 050618
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
1118 PM PDT Wed Jun 4 2025

.SYNOPSIS...Gusty northerly winds will continue to diminish each
day through the week, but remain robust with steep elevated seas
over the coastal waters. Hot and dry weather will continue each
day this week as a ridge remains parked offshore. Hotter weather
in the interior is expected this weekend.


&&

KEY MESSAGES:

- Strong gusty northerly winds at the coast forecast to diminish
  on Friday, becoming lighter and variable over the weekend.

- Above normal temperatures expected to continue in the interior
  through this weekend.

- Moderate HeatRisk increasing this weekend with hotter afternoon
  temperatures in the interior.

- 15% chance for isolated thunderstorms Klamath Mountains and 10%
  chance for Yolla Bolly Wilderness area Sunday through Tuesday
  next week.

- Gusty northerly winds for coastal areas increasing early to mid
  next week.



&&

.DISCUSSION...No significant changes to the previous forecast.
Stratus returned to around the Humboldt Bay and Eel River Valley,
while southerly flow reversal push northward the stratus south of
Cape Mendocino. Otherwise, stratus are expected to clear out late
in the morning, with another sunshine day. Afternoon temperatures
are forecast to be similar like Wednesday, with interior highs in
the low 80`s to mid 90`s. Coastal areas highs will prevail in the
upper 50`s to mid 60`s due to the marine influence.

Breezy to windy northerly wind persist over the coastal headland
and more prominent ridges along the North Coast. A strong
pressure gradient will continue to gradually diminish along the
North Coast through the end of the work week, while a low pressure
system continue ejecting southward. Gusty winds will linger over
higher elevations and particularly at the King Range and, the
coastal headland and Klamath Mountains of Del Norte County.


.Previous Discussion.../Issued 138 PM PDT Wed Jun 4 2025/...
Warm and dry conditions will endure over Northwest California
throughout the week as the ridge persists over the eastern
Pacific. Slightly warmer than average high temperatures can be
expected through the week, especially for the interior. More
average to slightly above average high temperatures are forecast
for the coast this week, with the possibility of marine stratus
over typical coastal areas each night. There is a potential for a
moderate HeatRisk over various interior areas, especially for
Trinity and Lake counties Thu and Fri.

Moderate HeatRisk is forecast to expand in coverage over the
weekend as the southern edge of a 500mb height anomaly and 850mb
temperature anomaly builds over the Pac NW; Oregon and Washington.
With 850mb temps soaring to 22C or more, some of the warmer
locations in Trinity and NE Humboldt Counties will reach 100-102F
this weekend. Granted Big Bar Raws will probably be hotter; 106-108F.
The robust N-NE flow is forecast to abate over the weekend and
marine air and stratus will most likely mitigate the HeatRisk for
western portions of Mendocino, Humboldt, and Del Norte Counties.
Marine air intrusion via the Russian river valley and southerly
winds will probably keep southern Mendocino from getting to 100F
this weekend. It will still be hot and we will continue to message
moderate HeatRisk in a weather story graphic.

Another potential impact going into the weekend into early next
week will be a low chance (10-15%) for diurnally triggered and
terrain forced thunderstorms over the Klamath Mountains and Yolla
Bolly`s. A semi-closed low aloft (700-500mb) is forecast to bring
an increase in mid level humidity and E-SE flow Sat-Sun. Coverage
of tstms - if any - is initially forecast to be quite sparse and
isolated over the highest terrain with very dry air in the lower
atmosphere and long thin CAPE profiles aloft. GFS model continues
to crank out much higher convective parameters on Sunday and Monday
and suspect this is probably overdone.

Mid level cyclonic circulation is forecast to slowly meander
across the area early to mid next week. How fast and exactly where
are largely unknown with considerable discrepancies between the
GFS and ECMWF tracks and positions. As one might expect for this
time of year, moisture does not look to be in abundant supply.
Main impacts - if we get any storms - appear to be CG strikes and
gusty outflow winds given inverted-V profiles indicated by the GFS
model. NBM 12hr thunderstorm probabilities do increase over the
weekend into early next week. We will continue to message these
low chances in the fire weather planning forecast. New ignitions
are possible, but fuels are not quite receptive yet (marginal at
best for Lake and Mendocino zones) for large and rapid fire
growth. /DB


&&

.AVIATION...Stratus is on the Humboldt coast this morning bringing
IFR conditions to KACV. This is not expected to make it as far north
as KCEC although there could be some mist around at daybreak. Breezy
winds are expected again this afternoon in Crescent City, but
farther south winds are expected to be lighter. KACV is expected to
clear with the increased mixing during the day, but clouds are
expected to come back in the evening and eventually move north into
KCEC. This morning KUKI has southerly winds there is widespread
stratus in Sonoma county. It looks like the marine layer is deep
enough that it will be able to advect north and over the mountains
into the Ukiah valley. This may bring a few hours of CIGS under 1
KFT, although confidence is low on this. MKK


&&

.MARINE...Northerly winds continue across the waters this morning
with the exception of the near shore waters off the Humboldt coast.
An upper level low approaching the area is expected to diminish
winds for areas south of Cape Mendocino and especially closer to
shore. Light southerly winds are expected in this area as well. Near
gale to gale force winds continue in the northern outer waters. This
will likely propagate some steep seas in the southern outer waters
after the gale ends so have added a hazardous seas warning through
this evening.

Thursday night into Friday the stronger northerly winds continue to
push farther off the coast and the southerly wind reversal near the
coast is expected to reach Pt St George. Friday morning there may be
a few lingering gale force gusts in the northwest portion of Zone
470. 15 to 25 kt winds linger in the outer waters through much of
the day, although there is some uncertainty on how quickly this
will evolve.

For the weekend winds are expected to drop to around 10 to 15 kt as
the upper level low and surface reflection move over the area. The
models are still struggling with the exact evolution of this which
will impact the exact speed and direction. However confidence is
growing that the winds will be fairly light and no significant
swells are expected. Sunday night into Monday winds are expected to
start increasing once again as high pressure builds back in. MKK


MKK



&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
None.
NORTHWEST CALIFORNIA COASTAL WATERS...
     Small Craft Advisory until 3 AM PDT Friday for PZZ450.

     Small Craft Advisory until 3 AM PDT Thursday for PZZ455.

     Gale Warning until 3 AM PDT Friday for PZZ470.

     Gale Warning until 9 AM PDT Thursday for PZZ475.

     Hazardous Seas Warning from 9 AM to 10 PM PDT Thursday for
     PZZ475.

&&

$$

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