238
FXUS66 KEKA 291220
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
Issued by National Weather Service Medford OR
520 AM PDT Sun Jun 29 2025

.SYNOPSIS...Hot and dry weather will peak Sunday with highs near 100
for the interior. Warm and Sunny weather will even approach the
coast by Sunday. There is a chance for scattered thunderstorms over
the interior Monday and Tuesday.


&&

.DISCUSSION...Heat draped across the interior Saturday
with highs just barely reaching 100 in the hottest valleys. High
pressure will peak Sunday. Highs will most likely peak right around
100 along the Trinity and Russian River Valleys with highs in excess
of 90 reaching as close to the coast as Myers Flat in Humboldt and
Boonville in Mendocino. The confidence in highs of at least 100 is
high (70 to 90%) but there is very little chance of any highs over
105 (10 to 30%). Cooling will remain good overnight with lows in the
60s. This will help keep general HeatRisk only moderate with
isolated high HeatRisk in Trinity County. High pressure and easterly
flow will both help shallow and weaken the marine layer this
weekend. Should clouds clear out fast enough, highs on the coast
will likely crest in the low 70s this weekend (50% chance from NBM).

High pressure will gradually break Monday and Tuesday as low
pressure skirts just south of the area into the Central California
Coast. Breaking high pressure will help to decrease highs back into
the 90s and pull more marine influence back along the coast, though
offshore wind will most likely keep marine influence shallow and
sporadic Monday and Tuesday. Global ensembles show a strong and
consistent signal that the low will also help enhance midlevel
instability with CAPE of 500 to 1000 J/Kg. Moisture pulling up the
Sacramento Valley and then pushing up over the coastal mountains
will provide the final ingredient for thunderstorms. There is much
higher confidence (30% chance) of isolated to scattered
thunderstorms over the interior Monday and Tuesday afternoons,
mostly concentrated over high terrain during the peak heat of the
afternoon. Theses storms could approach the coast with the RRFS
showing returns as near Kneeland. Though Precipitable Water is
modeled between 0.6 and 1.0 inches, dry air at the surface and
moderate steering flow (10 to 20 Kts from the SE) will generally
reduce rainfall at any given point. CAMs indicate the highest risk
Monday will be in Trinity County with storms extending west to around
Hoopa and along the Klamath Basin. This is an increasing signal (15%
chance) of thunderstorms near Southfork ridge early Sunday
morning with robust convection then over Trinity and the Yolla
Bollys Sunday afternoon. There does remain some uncertainty as
small shifts in the low pressure could greatly influence the
strength and location of storms. Beyond storms, there is high
confidence that the general pattern will remain warm, dry, and
benign. /JHW


&&

.AVIATION...12Z TAFs...A shallow marine layer looms over the coast
into the early morning hours of Sunday. Winds at coastal
terminals are forecast to be light with periods of southerly flow
right along the coast. Through the day, mostly westerly to
northwesterly winds are expected for coastal terminals. The
shallow marine layer this morning is creating IFR ceilings around
Humboldt Bay with mostly MVFR to occasional IFR conditions along
the Del Norte Coast. Lifting of ceilings and general clearing is
forecast as winds pick back up late this morning into the
afternoon. Another shallow marine layer is expected along the
North Coast very late tonight and into very early Monday morning.
VFR conditions are expected at UKI and most interior areas. /JLW


&&

.MARINE...Gale force northerly winds are forecast across the
northern outer waters through Sunday morning, followed by large
and steep waves Sunday afternoon. Strong winds over the outer
waters will create steep waves for the southern inner waters
through Sunday morning, while steep seas will prevail in the
northern inner waters. Potential for gale force northerly winds
and large steep waves are forecast to increase early to mid next
week.


&&

.FIRE WEATHER...Hot and dry conditions will peak Sunday with highs
near 100 and minimum RH in the mid teens. RH recovery has slightly
worsened to near 70% in valleys early Sunday and likely again early
Monday. Thankfully, winds are mostly diurnal and terrain driven with
only short lived gusty conditions each afternoon.

Low pressure skirting the area will help slightly ease temperature
and RH Monday and Tuesday but will also bring a chance of scattered,
mostly dry, thunderstorms. There is a very weak indication of
isolated storms forming overnight early Monday morning (10%), most
likely over the interior and then moving east towards the coast in
Trinity and Humboldt Counties. There is a much stronger signal of
thunderstorms forming over high terrain during the afternoon on
Monday and Tuesday (30% chance). The greatest chance of storms Monday
will be for the northern half of the area over northern Trinity and
Humboldt Counties. Any storms have the potential to drop between 0.6
and 1.0 inch of rain in there cores, but moderate storm movement (10
to 20 kts from the SE) and dry air at the surface will still likely
provide ample opportunity for lightning to strike dry fuels. The
newest convective models show a notable signal for isolate
thunderstorms over southern Humboldt COunty early Tuesday morning
and then robust convection over Trinity County and the Yolla Bollys
Tuesday afternoon. With the signal for convection is consistent,
exact location remains variable and uncertain s small changes in
the path of low pressure can have large impacts. /JHW


&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
     Fire Weather Watch from Monday morning through Monday
     evening for CAZ204-211-212-277-283.

NORTHWEST CALIFORNIA COASTAL WATERS...
     Small Craft Advisory until 11 PM PDT Monday for PZZ450-475.

     Small Craft Advisory until 11 AM PDT this morning for
     PZZ455.

     Gale Warning until 11 AM PDT this morning for PZZ470.

     Hazardous Seas Warning from 11 AM this morning to 11 AM PDT
     Monday for PZZ470.

&&

$$

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