Talmage, California Weather Forecast Discussion

383
FXUS66 KEKA 212123
AFDEKA
AREA FORECAST DISCUSSION
National Weather Service Eureka CA
223 PM PDT Sun Sep 21 2025
.SYNOPSIS...Warmer and drier weather will gradually build in Sunday
through Tuesday. A wetter pattern could emerge by mid week.
&&
.DISCUSSION...The early effects of upstream ridging and
northerlies are helping scatter out the previous procession of
layered stratus and low clouds that have lingered over the coast.
Fair conditions today will battle with the inevitable prevailing
coastal norms. Lingering cloud cover will generally promote
subdued conditions through the day. Building northwest flow will
help push out mid and upper level clouds for the interior, but
will also likely reinforce a gloomy marine layer to a lesser
degree tonight.
There is high confidence that high pressure will at least briefly
arch over the area Monday and Tuesday, allowing interior highs to
crest back into the 90s. The marine layer onshore will likely become
more diurnal with better clearing in the afternoon but shallow fog
and stratus overnight, especially in wind protected areas such as
Humboldt Bay.
There remains decent forecast uncertainty by mid next week. The
majority of models show a cutoff low meandering into southern
California. The impacts of this motion are more uncertain. While
moderated temperature and greater cloud cover are a near
certainty, there is wide disagreement for rain potential. While
the low will pull up moisture form the south, the general
northeast flow around the low will not be favorable for widespread
wetting rain. Showers that do form will most likely be around the
rim of the Sacramento Valley where the wind best aligns with
topography. The vast majority of models suggest a cooler and more
moist pattern through the end of the month, with long range
predictions of above normal precipitation. /JHW /EYS
&&
.AVIATION...(18Z TAFs)...Improvements to flight conditions are
likely to last until later tonight at the coastal terminals.
Despite lengthy periods of LIFR at KACV and KCEC this morning,
fluctuations due to low cloud base and overcast skies have
settled as of 20z. Visible satellite imagery shows the affects of
subsidence accompanied with northerly winds scouring clouds out,
should keep VFR in play until tonight. Model guidance shows sub
500ft cloud base 78% likely to return after midnight at KACV. KCEC
will fair better according to probabilities which point at 35kt are probable in
expansion fans that shed off Cape Mendo and Cape Blanco. In fact,
HREF chances for gale gusts are about 70% in the lee of Cape Mendo
and 50% for the northern outer waters. Coverage appears insufficient
to warrant a gale warning. Seas will respond to these stronger
northerlies with wind waves building up to 7-9 ft by Monday
afternoon and evening as a short period NW swell around 6 ft at 12
seconds builds. These two wave groups will combine into significant
wave heights around 10-12 feet with spectrum maximum wave heights
from 18-22 feet possible by Monday evening. Northerlies are forecast
to slacken off Tue into Wed with steep northerly wind waves falling
off on Wed. This break down in the pressure gradient will be in
direct response to another trough the will approach Central
California. Northerly winds and steep wave may begin to increase
late next week after this trough heads eastward into the Great Basin
and Desert SW. Inexperienced mariners, especially those operating
smaller vessels, should avoid navigating in hazardous conditions.
&&
.FIRE WEATHER...High pressure building early this week will
quickly warm and dry conditions. Highs will likely peak Tuesday
with the hottest valley just shy of 100 and min RH in the upper
teens. Northeast afternoon winds will also be slight enhanced
Monday and Tuesday afternoon around the rim of the Sacramento
Valley with some gusts in Lake County likely up to 25 mph.
Conditions will slightly ease (particularly daytime RH) Wednesday
and beyond. There is a slight chance of thunderstorms for
Mendocino and Lake Counties on Wednesday. /JHW
&&
.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
None.
NORTHWEST CALIFORNIA COASTAL WATERS...
     Small Craft Advisory from 6 PM this evening to 3 AM PDT
     Tuesday for PZZ455.
Small Craft Advisory from 3 AM to 11 PM PDT Monday for
     PZZ470.
Small Craft Advisory until 11 PM PDT Monday 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

NWS EKA Office Area Forecast Discussion