034
FXUS66 KEKA 202225
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
325 PM PDT Mon Jul 20 2026

.KEY MESSAGES...

* Warmer temperatures are bringing minor to moderate HeatRisk
  through Tuesday.

* Slight chance of showers and thunderstorms across the interior
  through Wednesday with the biggest threat Wednesday afternoon.

* Near or slightly below normal temperatures late in the week.

.SYNOPSIS...Monsoon moisture is bringing widespread high clouds
this afternoon and this is expected to continue through Wednesday.
Slightly above normal temperatures continue Tuesday. There is a
slight chance for afternoon thunderstorms in the interior Tuesday
and Wednesday. Drier weather is expected late in the week with
temperatures near or slightly below seasonal normals.

&&

.DISCUSSION...An area of low pressure, the the remnants from
Hurricane Elida, is moving up off the California coast. This is
bringing moisture with it. Today this is bringing mainly high
clouds and a few light showers or sprinkles. There is only
minimal, if any instability with this moisture which is limiting
the thunder potential. The better dynamics remain off the coast.
So don`t really expected any thunderstorms this afternoon, but
hard to rule one out. Warmer temperatures are expected again
Tuesday with highs in the warmer valleys in the mid to upper 90s.
Tuesday late in the afternoon and evening some of the models are
showing a small amount of instability, but there really isn`t any
forcing to set off a thunderstorm. Still one or two are possible
in northern Trinity county in the evening.

Wednesday the area of low pressure starts to move past the area
and this is expected to bring a little bit of forcing and some
instability in the afternoon and evening. This looks like the most
likely time for thunderstorms to develop this week. However, if
any storms do form they will be moving north and may move into
Siskiyou county fairly quickly.

Thursday the upper level trough is expected to get closer to the
area and this is expected to start bringing cooler temperatures,
back to near or slightly below normal with highs in the upper 80s.
This is expected to bring some stronger wind west to southwest
winds in the afternoon. Similar temperatures and winds are
expected to continue on Friday. For details see the fire weather
section. High pressure is expected to bring warmer temperatures to
the area for the weekend with dry weather.

&&

.AVIATION...Skies have cleared out this afternoon, but stratus
remains 5 to 10 miles off the coast. This is expected to move
back in this evening, but confidence is low on how quickly it will
return. It will likely return around sunset. When clouds do
return, models are indicating conditions will quickly drop to LIFR
and possibly less than a quarter mile. VFR conditions are expected
to return fairly quickly on Tuesday.

&&

.MARINE...Light northerly winds continue on the offshore waters,
but closer to the coast winds are light and south to southwest.
The steeper are diminishing this afternoon as well. A 3 to 4 foot
southerly swell at 12 seconds is moving through the waters along
with a 2 foot northwest swell.

These conditions are generally expected to continue through much
of the week. The swells will fluctuate slightly, but generally
remain small. Winds are expected to increase slightly to 10 to 15
kt Tuesday night and early Wednesday before diminishing again to
less than 10 kt. Thursday afternoon northwest winds start to pick
up once again in the southern waters to around 10 to 15 kt. Winds
continue to increase over the weekend. MKK

&&

.FIRE WEATHER...Monsoonal moisture has brought widespread high
clouds to the area this afternoon. There is still the potential
for a few dry thunderstorms this evening, but the chances are
diminishing due to very limited instability. Tuesday There is
another chance for thunderstorms, but this looks like a low
probability. Some weak ridging pushes over the area keeping the
strong inversion at higher levels. Did add a slight chance for
northern Trinity county late in the afternoon and evening.
Wednesday the upper level low related to the departing tropical
system moves closer to the area and increase the potential for
some thunder in the afternoon. Confidence remains low on this, but
have added thunderstorms to the forecast Wednesday afternoon and
evening.

Thursday and Friday the threat for thunderstorms diminishes,
however some stronger west to southwest winds are expected. At
this point it looks like the RH will be too high to warrant a fire
weather watch. Will likely add a headline to the forecast once it
gets within range of the higher resolution models if the winds
remain in the forecast. MKK

Afternoon RH continues to be low with most
interior areas seeing teens and 20s. High temperates return closer
to average early week as high pressure weakens. Winds generally
remain light and terrain driven. Monsoonal moisture has arrived
and will continue to influence the area through Wednesday. There
will be multiple low chances (15% or less) of thunderstorms for
the interior areas tonight through Wednesday. Dry low levels will
limit precipitation from reaching the ground.

&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
     Red Flag Warning until 6 PM PDT this evening for CAZ403-406-
     409>412.

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.

Visit us at https://www.weather.gov/eureka

Follow us on Facebook and Twitter at:
https://www.facebook.com/NWSEureka
https://www.twitter.com/NWSEureka

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