479
FXUS66 KEKA 132007
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
107 PM PDT Fri Jun 13 2025

.SYNOPSIS...Breezy winds forecast today and Saturday, with the
strongest winds on coastal headlands and in Lake County. Minor
HeatRisk in the interior forecast through mid next week.

&&

Key Messages:

* Minor HeatRisk in the interior valleys through mid next week.

* Gusty westerly-to-northwesterly breezes with low daytime
  humidity in the interior valleys today and again on Monday.

* Stronger coastal northerlies today and Saturday.

&&

.DISCUSSION...

Broad upper level trough will remain offshore over the northeast
Pacific through the weekend. High temperatures in the interior
valleys will trend warmer over the weekend with most interior
sites in the mid to upper 80`s by Sunday. Minor HeatRisk may still
impact individuals who are extremely sensitive to heat. Stronger
afternoon and evening west-to-northwest breezes are expected for
many of the interior valleys today. Gusts generally from 15-20 mph
are likely (60% chance or higher), though wind channeled valleys
and ridges will have stronger gusts from 25-35 mph. Coastal
northerlies will also increase today (Friday) and gusts from 35-40
mph are possible (90% chance per the HREF and ECMWF ensemble)
over the headlands; Pt St George and Cape Mendo.

W-SW flow aloft with embedded shorter wavelength troughs will
occasionally traverse into the Pac NW this weekend generating
occasional high level cirrus or cirro-stratus. SW flow is dry and
precip chances remain quite low, near zero. Larger scale trough
passage is forecast to occur on Monday, disrupting the interior
warm up. Precip and thunder potential with this trough remains
well to the north and northeast of our forecast area and do not
have a compelling reason to modify NBM output at this point.

Warming trend will resume in the interior Tue-Wed as a broad and
flat 500mb ridge builds in the wake of the trough. Probabilities
for high temps in the lower to mid 90`s (90-95F) will increase by
Wed in Lake, central and eastern Trinity and NE Mendo. Not so sure
about SE Mendo with about 5F degrees of interquartile spread
(86-91) at places like Ukiah and potential for marine air
intrusion. Higher PWATs spill over the offshore ridge in westerly
flow Tue-Wed next week. Chances for a few hundredths of an inch of
precip increases a bit. With very little or no impacts from this
minuscule amount of drizzle, will not adjust any of the NBM precip
probabilities at this time.

Highs will begin to trend downward toward the latter portion of
next week (Thu-Fri) as another mid level 500mb trough digs
southward offshore from the Gulf of Alaska. Ensemble clusters
reveal considerable variance with the evolution and rates of 500mb
height falls. One cluster (17% of members) indicates above normal
heights and continued ridging on Friday. This uncertainty is
reflected in NBM interquartile spreads of high temps; on the order
of 5-8F for interior valleys. NBM 24hr precip probabilities (less
than 10%) for 0.10 of an inch increases for Del Norte County
around Friday. Otherwise, main impact with this late week trough
appears to be cooler temps and perhaps enhanced diurnal winds in
the interior. Depending on where the trough ends up and how it
digs into the Pac NW/Great Basin (inside slider), it could also
result in stronger north-northeast winds with increase fire
weather concerns for Lake and eastern Mendo.

&&

.AVIATION...

18Z TAF) Inland terminals can expect VFR conditions with
afternoon gusty winds westerly winds building then calming
overnight. Along the coastal terminals, skies are beginning to
clear. Brief broken to few ceilings at 1500-2000ft are expected
before giving way to clear skies. The biggest forecast challenge
today will be the strength of the winds along the coast. High
Resolution models show gusts possible up to 30kts. This can lead
to some low level turbulence should be expected in the lowest
level of the atmosphere along coastal terminals. Tonight, there
are mixed signals of stratus returning to the coast. LAMP guidance
shows a 40- 50% probability of MVFR ceilings returning overnight
to KACV before mixing away by midday on Saturday


&&

.MARINE...

As the land-sea surface pressure gradient strengths, strong
northerly winds will continue to increase throughout the waters
today and into the weekend. Strong to near gale force gusts are
expected across the coastal waters. In localized areas downwind of
Pt St. George and Cape Mendocino, gale force gusts of 35kts are
likely during Friday and Saturday afternoon hours. A Gale Warning
was not issued due to the limited area of these expected enhanced
winds. However, steep short period wind waves will fill into the
inner waters creating hazardous conditions for smaller crafts
leading to widespread small craft advisories across the waters
through Sunday early in morning. Winds and seas remain be elevated
through the weekend, especially in the outer waters where the
impact of coastal nighttime easing of the winds will be less
prominent. Strong northerly winds forecast to decrease slightly
and retreat to the southern waters early next week.


&&

.FIRE WEATHER...

Gusty west-to-northwest breezes continue today in the interior
valleys. Generally gusts are forecast to peak around 15-20 mph in
the afternoon and evenings. Some higher gusts are possible in
eastern Lake, Mendocino, and Trinity counties. HREF is showing
good probabilities for areas of eastern Lake to see higher gusts
of 25-30 mph this evening and afternoon. Min RH remains low
(10-20%), but overnight recoveries remain good (50%+) in the
valleys. Recoveries in the higher terrain of eastern Lake and
Mendocino are worse (20-40%). Afternoon winds remain breezy in
eastern Lake, eastern Mendocino, and Trinity counties for much of
next week accompanied by low afternoon RHs. The combination of
these gusty winds and low RH`s may enhance the risk for small and
fast spreading grass/brush fires, particularly in Lake County. Low
RH`s and gusty west-northwest breezes are expected to continue in
the interior valleys this weekend and all of next week.

&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
None.
NORTHWEST CALIFORNIA COASTAL WATERS...
     Small Craft Advisory until 3 AM PDT Sunday for PZZ450-455-
     470-475.

&&

$$

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