014
FXUS66 KEKA 032146
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
246 PM PDT Wed Sep 3 2025

.SYNOPSIS...High pressure remains over the area through Thursday
and is expected to bring another hot and generally dry day across
the area. Friday and into the weekend an upper level trough is
expected to gradually cool the area down. Monday there is a chance
for a wetting rain in the northern portion of the area and highs
only in the 70s.

&&

.DISCUSSION...The upper level trough that brought cloudiness and a
few showers last night is moving off to the north. A few showers
are still developing this afternoon in northern Del Norte county.
There is Cu developing across Trinity county, but it generally
looks fairly flat and the instability is limited. Still a stray
showers is possible before peak heating ends. The marine inversion
remain strong this afternoon and the coast is expected to remain
mostly cloudy with just a few breaks. Thursday is expected to be
another hot day, although it may be a few degrees cooler than
today. There is a slight chance for a thunderstorm or two in the
afternoon in northern Trinity county.

Thursday night into Friday the next trough starts to push onshore.
This will bring a deep marine layer as well as the potential for
coastal drizzle. So have added patchy drizzle to the coastal areas
overnight. This will keep high temperatures only around 90 in the
warmer areas and potentially cooler than that. The trough is
expected to linger through the weekend. This will keep high
temperatures in the 80s in the far inland areas. A deep marine
layer and some coastal drizzle possible and this will keep some of
the near coastal areas cooler. Some of the models are showing
this precip making it farther inland, but have held off on adding
that to the forecast.

Monday looks like the better chance for a wetting rain, but only
as far south as Humboldt and Trinity counties. The three of the
ensemble clusters show precip moving in with this system, but
there is still one that keeps NW CA mainly dry. There are also
some differences in how far south they take the precip. The ECMWF
shift of tails is highlighting this uncertainty as well.
Mendocino and far northern Lake county could see a few light
showers or sprinkles, especially in the northern mountains, but
again this will depend on which ensemble cluster pans out. These
may be convective showers, but lapse rates aloft are pretty poor
so am not expecting thunderstorms at this point. Continued cooler
and possibly wet weather is expected on Tuesday as well. MKK


&&

.AVIATION...LIFR conditions inundate the coastline and adjacent
river valleys this morning. The marine inversion looks to be holding
strong through the end of the week as higher geopotential heights
come into the area. Model guidance shows KACV and other terminal
sites could briefly lift out of LIFR categories this afternoon
(~50%). There is greater confidence that ceilings will persist and
simple get higher. Winds expected to be light with the marine layer
returning tonight and degraded visibilities after dark. Inland,
storm potential has decreased today. Gusty diurnal winds are
forecast to develop this afternoon with gusts of 15-20kts possible.
Coastal river valleys are expected to have stratus overhead
tonight, although at this point it isn`t expected to make it into
Ukiah.

&&

.MARINE...Northerly are expected to remain breezy through tomorrow
midday across the outer waters. An incoming early season cold front
will cool down inland temperatures. This cooling will cause the land-
sea pressure gradient to weaken lowering winds in the inner waters
first, before weaken all marine winds by Friday. Wind waves remain a
threat in the outer waters through 3 PM tomorrow with localized
conditions that could be hazardous to small crafts. Small, mid-
period NW and SW swells will persist through the weekend. Overall
conditions predicted to calm into the weekend through early next
week.

&&

.Fire Weather...Wind threat is decreased today to usual diurnal
flow with afternoon gusts, but warm temperatures and very low
afternoon RH with poor overnight recoveries in the high elevations
are forecast to continue through Thursday. An approaching upper
level low/trough will bring a slight chances (10-20%) of
precipitation across the northern portion of the area Friday.
Nighttime RH recoveries are expected to improve as this moves
through the area. Cooler weather with below normal temperatures
and generally higher relative humidity for this weekend. A better
chance for wetting rain is expected in Humboldt, Del Norte and
Trinity counties. Some light rain or sprinkles are possible
farther south as well. MKK

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
None.
NORTHWEST CALIFORNIA COASTAL WATERS...
     Small Craft Advisory until 3 PM PDT Thursday for PZZ470-475.

&&

$$

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