037
FXUS66 KEKA 042038
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
138 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 Friday.

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

- 15% chance for 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...A strong pressure gradient continues to gradually
diminish along the North Coast. High pressure out in the eastern
Pacific continues to push against a low pressure system ejecting
further south of Northwest California. Northerly winds over the
region will continue to diminish along the North Coast through the
end of the week. The highest gusts will linger over higher
elevations and particularly at the King Range and the Klamath
Mountains of Del Norte County.

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.

&&

.AVIATION...

18Z TAF: VFR conditions prevail with NW wind gusts 25 to
30 knots at CEC early this afternoon. A broad stratus deck has been
lingering just offshore and along the Humboldt coast, but so far has
not impacted the coastal terminals. A weaker stratus field is still
present along the Mendocino coast including Point Arena. Gusty
northerly winds will continue through the afternoon, pushing much
closer to the southern Humboldt/Mendocino coasts than in previous
days. Similarly, gusts 20 to 30 knots expected at CEC and ACV. As
winds ease at the surface this evening, LLWS is briefly possible
again at ACV as NE winds remain elevated aloft around 30 knots.
Winds will gradually ease at the surface overnight into early
Wednesday morning - HREF is indicating 50 to 75% chance of scattered
stratus ceilings <1000 feet and slight reductions in visibility
beginning late this evening, especially in and around Humboldt Bay.
Northerly winds will resume Thursday, but gradually begin to weaken
and push offshore. A greater chance for stratus development is
possible Thursday afternoon and evening as winds decrease.

&&

.MARINE...

Steep and hazardous seas continue to verify on the buoys
around 10 to 12 feet at 8 to 10 seconds, with seas up to 15 feet in
the outer waters. Gale force winds with isolated storm force gusts
are expected to continue in the outer waters through Thursday,
becoming isolated to the z470 through early Friday morning. Winds
and steep seas are also pushing further into the inner waters
(including z455) this afternoon than in previous days, necessitating
small craft advisories for both zones.

Conditions will begin to ease for the southern waters, especially
the inner waters, on Thursday as gales become confined to the
northern zones. An upper level disturbance will help weaken the
pressure gradient by Friday, confining gales to the far northwest
corner of z470 and seas to gradually follow suit. Calmer conditions
are expected this weekend with winds 10 to 20 knots, although the
exact timing of this transition to milder winds and seas is
uncertain - late Friday into Saturday.

&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
None.
NORTHWEST CALIFORNIA COASTAL WATERS...
     Hazardous Seas Warning until 3 PM PDT this afternoon for
     PZZ450.

     Small Craft Advisory from 3 PM this afternoon to 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.

&&

$$

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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For forecast zone information
see the forecast zone map online:
https://www.weather.gov/images/eka/zonemap.png