025
FXUS66 KEKA 222049
AFDEKA
AREA FORECAST DISCUSSION
National Weather Service Eureka CA
149 PM PDT Sun Jun 22 2025
.SYNOPSIS...Elevated fire weather conditions through today due to
breezy west to northwest winds and low humidity across eastern
Trinity, eastern Mendocino and Lake counties. A warming and
drying trend Monday through Wednesday. Risk of elevated fire
weather conditions returns mid to late next week.
&&
KEY MESSAGES:
* Elevated to locally critical fire weather conditions through
this evening for Lake, eastern Mendocino and eastern Trinity
Counties due to low RH`s and breezy west and northwest winds.
* Near to above normal temperatures are expected Monday through
Wednesday, with highs in the upper 80`s to mid 90`s across the
interior valleys.
* Fire weather concerns return mid to late week, with enhancing
west to northwest winds and low humidity.
&&
.DISCUSSION...Breezy west-nortwest winds and below normal
temperatures continue today as a passing upper-level trough slowly
eject the region. Increasing mid to high level clouds are
expected during the afternoon hours for Del Norte, Humboldt and
Trinity counties as the aforementioned trough continue to move
south- southeast. While mostly clear skies will prevail in
Mendocino and Lake counties. High temperatures are running up to
around 6 degrees warmer compared with yesterday`s reading across
much of the forecast area.
Tonight, a shortwave ridge build in quickly in the wake of the
departing trough. This will promote breezy north-northeast wind
flow over the interior higher terrain, especially in eastern Lake
County. Areas of fog and patchy dense fog are forecast to develop
overnight along the shelter valleys with clear skies and strong
radiational cooling. Near normal low temperatures return tonight,
with lows in the mid 40`s to mid 50`s across the valleys, with up
to low 60`s over the mountains in eastern Mendocino and Lake
counties. A shallow marine layer will gradually to redevelop
along the coast late tonight through Monday morning.
A warming and drying trend is forecast Monday through Wednesday
with highs in the lower to mid 90`s for the interior valleys,
peaking on Tuesday and Wednesday. However, a weak shortwaves low
will drive down across the eastern periphery of the ridge on
Monday. This will bring an increase of mid to high level clouds
across the area. Winds will be generally diurnal and terrain-
driven, with afternoon breezy west- northwest through the
channeled terrain. Morning coastal stratus are expected each day,
lifting and mixing during the afternoon hours.
Ensembles and deterministic models continue showing a series of
weak shortwaves moving across the area Wednesday through late
next week. Ensembles remain in good agreement with dry conditions
prevailing during the next 7 days forecast period. The scenario
with those shortwaves would bring temperatures few degrees cooler,
but may also increase west to northwest winds. ZVS
&&
.AVIATION...(18z TAF)...Aside for some very isolated and short
lived MVFR ceiling this morning, a weak marine inversion and
building winds have again allowed for widespread VFR conditions all
across the area. There is again potential but high uncertainty for
some MVFR to IFR conditions along the coast Sunday night into
Monday. Chances are lowest in exposed areas along the coast such as
Crescent City where there is less than a 30% chance of a ceiling
overnight. Anything that does form in these locations will most
likely be shallow but very localized LIFR fog that will quickly lift
past sunrise. There is some higher potential (60% chance) for MVFR
to IFR ceilings around Humboldt Bay, mostly forming after midnight.
Weaker winds will likely help any ceiling that does form hold on a
bit longer Monday morning compared to Sunday. /JHW
&&
.MARINE...Fresh to strong northerlies have have persisted across
the southern waters today. The northern waters have remained more
gentle but gusts up to 25 kts will spread north Sunday evening and
Monday before pulling back south. Similar gusty conditions will
continue through at least mid next week in the southern waters as
high pressure gradually forms along shore. The sea state will mostly
be controlled by short period wind waves as steep as 8 feet at 8
seconds. A very minor northwest swell up to 4 feet at 12 seconds
will start to build around early morning through the week. /JHW
&&
.FIRE WEATHER...Breezy to gusty westerly and northwesterlies
breezes continue today. Afternoon humidity in the 20`s to low
30`s percent in eastern Trinity, eastern Mendocino and Lake
counties. The combined of gusty west-nortwest winds yield in
elevated fire weather conditions in zones 264, 277 and 283 through
Sunday. Risk for small and fast spreading grass or brush fires
will increase. Overnight RH recoveries will be good across the
valleys, with moderate humidity recoveries over the higher terrain
in SE Mendocino and Lake counties.
A warming trend is forecast early through mid next week as a
surface high pressure build in. Daytime RH`s trend down as
temperatures increase next week into mid 90`s with breezy NW
afternoon winds.
Wednesday through late next week models are in a good agreement on a
series of shortwaves moving across the area. At this point,
ensembles remain dry with temperatures few degrees colder.
However, low afternoon RH`s values and enhancing west`northwest
winds will promote elevated fire weather conditions in Trinity,
interior Mendocino and Lake counties. ZVS
&&
.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
None.
NORTHWEST CALIFORNIA COASTAL WATERS...
Small Craft Advisory until 9 PM PDT Monday for PZZ455.
Small Craft Advisory from 9 PM this evening to 9 PM PDT
Monday for PZZ470.
Small Craft Advisory until 9 AM PDT Tuesday 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