440
FXUS66 KEKA 302152
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
252 PM PDT Mon Jun 30 2025

.SYNOPSIS...Fire weather danger has been enhanced by mid level
moisture and instability. Red Flag Warnings are in place through
Tuesday night for the interior areas. Temperatures ease through
the week


&&

.DISCUSSION...With an upper level low offshore of Southern-Central
California, the effects of high pressure have become muted.
Temperatures have eased a bit as clouds/moisture are being pulled
into the area with the top edge of the cyclonic/CCW flow. The
moisture at mid levels has increased steep lapse rates and given
buoyancy to air parcels, free convection at upper elevations with
high base thunderstorms could produce dry lightning and/or
downdrafts which could further exacerbate fire ignitions with
downburst or outflows as cold dense air drops out of the core. As
of this afternoon, isolated lightning and convective cells have
produced radar returns traveling NW through Trinity county and our
neighbors in Siskiyou, verifying previous forecasts and model
soundings. Confidence has increased for the convective outlook
for tonight and Tuesday with SPC including our CWA in a marginal
risk for severe thunderstorms with gusty/damaging winds from the
previously mentioned outflow ~60mph. We have upgraded the FW.A for
Tuesday into a Red Flag Warning matching the current FW.W with
the same fire weather zones 204, 211, 212, 277 and 283. Zone 203
has been included for Tuesday with HREF including Del Norte in
their probability of thunder, albeit slight. NBM also confirms
high CAPE values in the 2000-2800 j/kg range for interior Del
Norte. /EYS


&&

.AVIATION...18Z TAFs:  A shallow marine layer continued to result in LIFR
conditions at coastal airports today. Variable mid layer clouds
convection may disrupt the layer north of Cape Mendocino this
evening. For how long is not known. Visible satellite imagery showed
areas of stratus and fog lingering along the shoreline this
afternoon and suspect LIFR conditions to quickly redevelop this
evening with loss of daytime heating and mixing. LIFR ceilings below
500 feet and vsby`s 1/2SM or less are probable overnight into early
Tuesday at coastal terminals.

VFR concisions are forecast to prevail inland. A cutoff upper low
will meander off the central CA coast tonight into Tuesday and
will contribute to inland shower and thunderstorm activity. Some
of this activity may hold together as it makes its way
northwestward closer to Humboldt and Del Norte coast, but
confidence remains too low at this time for TAF inclusion. There
may be at the least gusty outflow winds as the storms pulse
stronger on the higher inland terrain. Sonoma county stratus will
once again make a run for the Mendo border overnight. Coastal low
clouds and fog may also spread into the Anderson valley.


&&

.MARINE...Large and steep waves are forecast to continue across the waters
through mid week. The one exception is Mendocino nearshore waters
where small scale eddies will continue to result in southerlies.
Highest waves around 14 feet are expected over the northern outer
waters where a hazardous seas warning remains in effect. Northerly
winds begin to ramp up tonight into Tuesday and a gale warning for
gusts to 40 kt has been hoisted for pzz470. Greater uncertainty for
gales exists for the southern outer waters (pzz475). Northerly winds
and steep waves will continue for the latter portion of the week,
but should trend down.

&&

.FIRE WEATHER...Hot, dry conditions continue to ease for the next
few days as low pressure morphs the ridging regime. High
temperatures ease throughout the remainder of the week.
Thunderstorms are the primary concern over Trinity and interior
Humboldt. Other counties like Del Norte and Lake have less of a
chance but are still being included as models fade at their
boarders in probability. Convective cells are currently being
observed via satellite and radar as of 20z today. Red Flag
Warnings are in place for the remainder of the day and lasting
into 11pm tonight. The fire weather watch for Tuesday has been
upgraded to a Red Flag Warning and includes zone 203, interior
Del Norte along with Trinity, interior Humboldt, eastern Mendocino
and Northern Lake counties. /EYS


&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
     Red Flag Warning until 11 PM PDT this evening for CAZ204-
     211-212-277-283.

     Red Flag Warning from 11 AM to 11 PM PDT Tuesday for CAZ203-
     204-211-212-277-283.

NORTHWEST CALIFORNIA COASTAL WATERS...
     Small Craft Advisory until 3 PM PDT Wednesday for PZZ450.

     Hazardous Seas Warning until 5 PM PDT this afternoon for
     PZZ470.

     Gale Warning from 5 PM this afternoon to 11 AM PDT
     Wednesday for PZZ470.

     Small Craft Advisory until 7 PM PDT Tuesday for PZZ475.

     Gale Watch from Tuesday evening through Wednesday evening
     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