571
FXUS66 KEKA 121946 AAA
AFDEKA

AREA FORECAST DISCUSSION...UPDATED
National Weather Service Eureka CA
1246 PM PDT Sat Sep 12 2026

.KEY MESSAGES...

* Red Flag Warning in effect for all towns and areas within Lake
  County Saturday for critical fire weather of strong winds and low
  relative humidity.

* Elevated fire danger for all interior areas this afternoon and
  evening.

* Chances for light rainfall for Del Norte and northern Humboldt
  this evening and overnight.

* Dry, near-normal conditions return early next week.


&&

.SYNOPSIS...Cooler temperatures are expected through into the
weekend. Light rain is possible for the Del Norte and northern
Humboldt today and tonight. Westerly to northwesterly winds will
bring elevated to critical fire danger for the interior this
afternoon and evening.


&&

.DISCUSSION...A trough and associated front will enter the area
today, considerably lowering interior temperatures to the 70s and
80s. The front will also bring a chance for rain to Del Norte and
Humboldt Counties. Del Norte has around an 80-90% chance to see
measurable rain, while northern Humboldt has around a 30-50%
chance. The chance for wetting rain (over 0.1") is around 10-30%
in northern Humboldt north of Eureka and 60-80% in Del Norte.
There is some instability modeled with this system, which may
allow for a thunderstorm to develop in an especially strong
shower. Because this will be showery, some areas can see locally
higher precipitation, perhaps as high as a half inch in areas of
Del Norte.

Post frontal westerly winds will strengthen this afternoon for the
eastern portions of the area. Wind gusts of 25 to 40 mph are
likely for much eastern Lake County, eastern Mendocino, and the
Trinity River Valley in eastern Trinity County. This will elevate
fire weather concerns, particularly over Lake County where the
strongest winds will coincide with dry conditions. A Red Flag
Warning is in effect for Lake County today, but elevated fire
weather conditions will exist for all the interior areas listed
above. There are also chances this fire threat continues Sunday
night and Monday for the far eastern portions of the area. See the
Fire Weather section below.

An omega-block pattern is likely to develop right off the Pacific
Northwest coast, with troughing remaining far east and far west.
Slightly over half of ensemble members do show an elongated
positively tilted trough or cutoff low over the area Wednesday.
This will contain little moisture and may only result in a slightly
deepened marine layer and perhaps some modest instability in the
higher terrain. Regardless, a dry, near-normal pattern looks likely
for the following week as the omega block stalls the storm track
for NW California. /JB


&&

.AVIATION...(18Z TAFs)...A front is approaching NW California
early this afternoon bringing in mid to high level cloud cover.
Breezy west-northwest winds are likely this afternoon and evening
over interior areas, including UKI. Winds aloft may continue
overnight over Trinity, eastern Mendocino, and Lake Counties which
will may lead to areas of low level wind shear and wave cloud
activity is already being observed. Generally light rain is likely
this evening and overnight for the coastal terminals with MVFR
ceilings likely during periods of rain. Brief IFR conditions are
possible should a heavier rain shower move near a terminal. The
marine layer is likely to remain disrupted as this front moves
overhead and widespread stratus reformation is unlikely. /JB


&&

.MARINE...An incoming front has weakened northerly winds and seas
have subsided significantly. A mid period south swell at around
3-4 ft along with these subsiding wind waves dominate the sea
state. South winds will increase this evening and overnight right
along the Humboldt and Del Norte Coasts with gusts of 15 to 20
kts. Elsewhere, winds remain light at less than 10 kts through
Sunday evening. Sunday night into Monday, northerly winds increase
again with near-gale to gale force winds force winds possible for
the outer waters by Monday.


&&

.FIRE WEATHER...A troughing pattern has brought breezier winds,
much cooler temperatures, and a deeper marine layer. Wetting rain
is possible for Del Norte and far northern Humboldt. Stronger
winds are forecast this afternoon and evening and gusts up to 35
mph are possible in Lake, southern Mendocino, and eastern Trinity
Counties, especially for higher, N-S orientated terrain. RH will
rise with this onshore push of winds to the 20s and 30s, but much
stronger wind gusts of 25 to 35 mph will support critical fire
weather conditions, particularly in Lake County. In the few hours
before the winds increase, hot and dry conditions are possible,
increasing the likelihood of critical fire weather conditions for
Lake County. A Red Flag Warning is in effect for Lake County until
2 AM Sunday. Other areas outside Lake County will still see
elevated fire danger, including eastern Mendocino and Trinity
County, despite not being within the Red Flag Warning area.

Winds ease Sunday and RHs increase slightly into the high 20s to the
high 30s for the eastern interior. Areas closer to the coast could
see afternoon RHs in the 50s with a much deeper marine layer. Sunday
night into Monday, an increase of northerly winds down the Central
Valley may elevate fire conditions again for the eastern portions
of the area, particularly eastern Lake County should the winds
end up on the stronger end. RH does trend upwards, so critical
conditions may be localized and brief.


&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
     Red Flag Warning until 2 AM PDT Sunday for CAZ418>421.

NORTHWEST CALIFORNIA COASTAL WATERS...
None.
&&

$$

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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