049
FXUS66 KEKA 140754
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
1254 AM PDT Fri Aug 14 2026

.KEY MESSAGES...

* Slight chance of interior thunderstorms today into Saturday.

* Smokey conditions likely from the MP18 Fire, focused in the
  Trinity River Valley and Trinity County.

* Cooler temperatures are likely through next week.


&&

.SYNOPSIS...A troughing pattern has set up over the region. Inland
areas can expect cooler temperatures with the coast continuing to
have overcast conditions and brief afternoon clearing. Passing
shortwave disturbances increase the chance for storms inland.


&&

.DISCUSSION...Last weeks high pressure center has migrated over east
TX and has become what seems to be a steady standing wave. This is
resulting in pronounced light troughing over the western seaboard.
Monsoonal moisture continues to flow northward through the Great
Basin area with some moisture reaching the Central Valley of
California. Shortwave disturbances are predicted to wobble their way
downstream of the upper level flow, increases vorticity and lift for
the west as well.

One result of this troughing besides cooler temperatures inland due
to less compressional heating is the increased chance for
rainshowers and thunderstorms for the interior. While moisture flow
is not too impressive, these shortwave disturbances could have
enough of an impact to promote convective activity through Saturday.
Thursday afternoons storm chances failed to materialize in NW CA, yet
tomorrow the atmospheric set up will be different.

High resolution models are starting to grasp a passing shortwave
disturbance tomorrow afternoon into the evening. The NAM12km model
shows the shortwave setting up with its axis directly off the North
Coast`s coastline. In addition, the HRRR Simulated IR model shows a
band of light convection racing through NW CA later Friday. That
said, there is limited moisture in the environment with approx. 0.2-
0.3" above normal PWAT values. In addition, smoke and cooler
temperatures will decrease instability. This means that while it is
likely that atmospheric forcing will be present, there is just not
enough "juice" in the atmosphere to really get any convection
started. However, any storms that DO form, will likely produce dry
lighting and should be taken seriously if spotted. Lightning
probability have been capped a "Slight Chance" for the area to
capture this unlikely, yet highly impactful, weather event.

Global ensembles show this synoptic feature continuing through next
work week. Expect relatively repetitive weather conditions for
the next 7 days.


&&

.AVIATION...Coastal terminals can expect IFR with periodic LIFR
through the end of the week. Winds will remain light (<10kts) for
the coast as well. Inland areas will experience enhanced terrain
forced winds with potential increased cloud coverage within river
valleys. Smoke continues for the Trinity River Valley and much of
Trinity County.


&&

.MARINE...A relatively weak trough has set up over the region. This
has caused a decrease in overall wind speeds. Waves remain steep,
yet they should continue to decay through the end of the week. A
southerly swell of ~3ft will build into the region by the weekend
and will mix with northerly shorter period waves. However, the
overall sea state should remain mixed with these two wave groups
through the start of next week. Light to moderately breezy (~20kt)
winds are expected through the extended forecast as of right now.


&&

.FIRE WEATHER...A troughing pattern has set up over the region. This
will result in lower daytime temperatures, increased RH values, and
stronger winds due to increased mixing. Inversion are forecasted to
be weaker and break earlier in the day. A deeper marine layer will
reach further up river valleys through the night as well, possibly
impacting any Rx burning operations.

This afternoon, there is a low chance (10-15%) of highly impactful
thunderstorms forming over the interior specifically for the
Klamath, Salmon, and Yolla Bolly Mountains. Forecast confidence is
very low due to decreased instability and relatively normal
moisture, however lifting will be amplified due to a shortwave
disturbance flowing over the region through the evening. Any storms
that do form will have motions towards the NE which should decrease
the chance of any impacts. However, DCAPE values remain amplified
enough create gusts capable of traveling down river valleys.


&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
None.
NORTHWEST CALIFORNIA COASTAL WATERS...
     Small Craft Advisory until 3 AM PDT early this morning for
     PZZ455.

     Small Craft Advisory until noon PDT today for PZZ470.

     Small Craft Advisory until 6 PM PDT this 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