120
FXUS66 KEKA 280754
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
1254 AM PDT Sat Jun 28 2025

.SYNOPSIS...Hot and dry weather will peak this weekend 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 early next week.


&&

.DISCUSSION...Friday saw the first bits of warming as
high pressure has begun to build across the area. The hottest
valleys returned to the 90s. A persistent marine layer kept the
coast cooler in the 60s, though more persistent clearing was able to
occur in the afternoon compared to earlier in the week. Overnight,
another extensive marine layer is evident along the coast, though
high pressure has made it shallower with ceilings only a couple
hundred feet off the surface.

High pressure will continue to build through the weekend with high
temperatures ratcheting up each day. Highs will most likely peak on
Sunday 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 early next week 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. Early convection models show a
very weak signal (10% chance) of isolated nocturnal thunderstorms
early Monday morning. Any storms that form overnight would likely
push to the coast form the east. There is much higher confidence
(30% chance) of isolated to scattered thunderstorms over the
interior Monday and Tuesday, mostly concentrated over high terrain
during the peak heat of the afternoon. This storms could approach
the coast with the RRFS showing return 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. Beyond storms,
there is high confidence that the general pattern next week will
remain warm, dry, and benign. /JHW


&&

.AVIATION...06Z TAFs...Satellite imagery depicts a deep marine layer
and stratus blackening much of the coastal waters north of Cape
Mendocino, and extended well up the Eel River. The stratus surge has
tried to move northward toward CEC without success. Mainly VFR
conditions are expected to prevail at CEC with increasing northerly
winds over the waters and offshore flow aloft as the high pressure
builds in. While MVFR to IFR ceilings at ACV, before LIFR conditions
develop overnight as the building high pressure aid in squash the
marine layer down slightly and strengthen the inversion. With the
weak inversion still in place on Saturday, expect ceilings lift and
mixing out after 17Z allowing VFR conditions. Surface NNW winds are
expected to increase after 18Z along the coast. Gusts up to around
35 kts are likely (80% chance) at CEC after 21Z.

For the interior and UKI, prevailing VFR conditions. Surface winds
at UKI generally light and variable, becoming SW as a thermal trough
develops in the interior.
/ZVS


&&

.MARINE...Gale Force gusts continue across the southern outer
waters overnight and into Saturday, before spreading into the
northern outer waters Saturday afternoon through Sunday. A Gale
Warning is now in effect from Saturday afternoon through Sunday
monring for the northern outer waters. Meanwhile, winds in the
southern inner waters will continue to slowly diminish through
Saturday, but conditions will remain hazardous for small crafts.
Steep seas are expected to propagate into the northern inner waters
Saturday afternoon. A Small Craft Advisory is now in effect for the
northern outer waters from Saturday afternoon through Sunday.

With a tightening pressure gradient early next week, conditions will
remain hazardous with strong to gale force northerly wind gusts and
steep to very steep seas across the coastal waters through much of
the upcoming week.
/ZVS


&&

.FIRE WEATHER...Hot and dry conditions will build into the weekend
with highs near 100 and minimum RH in the mid teens. RH recovery is
currently very good around 80% or more at low elevations, but it
will gradually worsen to closer to 60% as subsidence inversions
strengthen and lower through the weekend. 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 early next week but will also bring as 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). 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. Convective models will be watched closely as more become
available over the next few days. /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 from 1 PM this afternoon to 3 AM PDT
     Monday for PZZ450.

     Small Craft Advisory until 3 AM PDT Sunday for PZZ455.

     Small Craft Advisory until 1 PM PDT this afternoon for
     PZZ470.

     Gale Warning from 1 PM this afternoon to 11 AM PDT Sunday
     for PZZ470.

     Gale Warning until 11 PM PDT this evening 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