650
FXUS66 KEKA 102017
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
117 PM PDT Tue Jun 10 2025

.SYNOPSIS...Isolated thunderstorms Trinity County through this
evening. Interior temperatures forecast to diminish each day
through Friday.

&&

KEY MESSAGES:

* Isolated thunderstorms Trinity County through this evening.
  Strong outflow wind gusts from storms possible.

* Interior heat risk diminishing and becoming low for the
  remainder of this week.

* Gustier westerly and northwesterly breezes in the interior
  valleys each afternoon and evening Wednesday through Saturday.

* Strengthening coastal northerlies mid to late week.

&&

.DISCUSSION...

An upper level ridge over California will migrate eastward as a weak
upper level trough swings over our area from the north. This
synoptic weather change will ad variety to our daily weather. First
and foremost, there is CAPE aloft over the Klamath mountains,
allowing for daytime heating to pop into thunderstorms for one more
afternoon. The GFS is showing "Most Unstable CAPE" values centered
over Del Norte, Trinity, and Northeastern Mendocino County Tuesday
night. Brief wetting rain, cloud to ground lighting, and small (pea-
sized) hail is possible with these storms. upper level vorticity
will be present in the 700mb level which could help sustain some
thunderstorm briefly. However, the storms look relatively dry with
the troposphere being at 46% RH by 00Z/5PM.

Tuesday has a decreased chance in the NBM probability for thunder
with the Trinity Horn area having a 10-20% chance of thunderstorms.
Del Norte and NE Mendocino show only a 0-5% chance so confidence
remains low for storms developing in those areas. THe majority of
the convective development looks to stay much further east of CWA in
southern OR and NE CA. Potential for gusty winds and dry lightning
could be a fire weather concern for these areas. This incoming
trough looks quite dry and main impacts appear to be a return of
stronger gusty winds and cooler temperatures.

Inland valleys will struggle to break 90F on Wednesday through the
rest of the week and weekend. High tempertures look to be around the
low 80s at the warmest for inland valleys Friday and Saturday as of
right now. This comes a relief after what has been a warm couple of
weeks to start meteorological summer. These cooler temperatures will
also be accompanied by stronger winds with afternoon wind gusts
around 15-20mph in the later portion of the week.

&&

.AVIATION...

10/18Z TAFs...IFR ceilings along the coastal terminals with a
strong low level inversion early this afternoon. Stratus will
continue to erode back to the coast with the diurnal heating.
However, mainly IFR ceilings are expected to persist at ACV and
CEC with small scale cyclonic eddies along the coast keeping the
shoreline with low clouds moving in and out. LIFR conditions are
forecast to redevelop this evening and tonight, with ceiling
around FL002-FL004 and visibility in mist/fog. HREF model guidance
for visibility suggest there is a 20% chance of at least 0.5SM or
less overnight at both coastal terminals. Meanwhile, prevailing
VFR conditions at UKI. Surface winds generally out of WSW at 5-10
kts at all TAF terminals, with some occasional gusts up to 15kt at
UKI.

&&

.MARINE...

Gentle to moderate northerly breezes continue to spread across
the coastal waters today. Winds will continue to gradually increase
across the outer waters through the work week. Locally near gale
to gale force wind gusts is forecast to develop leeward of Cape
Mendocino Wednesday afternoon. Widespread fresh to strong northerly
breezes with some near gale force gusts downwind of Cape Mendocino
begins on Thursday and then continues into the weekend as the
high pressure stalls over the eastern Pacific and the pressure
gradient tightens up along the coast.

Mid period northwest swell will continue to dominate the sea
state through mid week. In addition, a long period southwest swell
of 3-4 feet at 17 seconds will slowly subside through Thursday.
This could present a small sneaker wave threat on south facing
beaches if it ends up coming in this big. Wind driven seas are
expected to increase on Thursday and Friday.

&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
None.
NORTHWEST CALIFORNIA COASTAL WATERS...
     Small Craft Advisory from 9 PM this evening to 9 PM PDT
     Wednesday 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