334
FXUS66 KEKA 202148
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
248 PM PDT Sun Sep 20 2026

.KEY MESSAGES...

* Warmer and drier interior temperatures begin to slowly ease on
  Monday.

* A shallow but strong marine layer along shore will weaken with
  some clearing by possible by Tuesday.

* Cold front late in the week with a 20% chance of light wetting
  rain along the North Coast.


&&

.SYNOPSIS...High pressure has peaked today with warm conditions
across the interior and thin but persistent marine clouds near
shore. Low pressure passing south will cool conditions in the coming
days with clearer skies possible along shore by Tuesday.


&&

.DISCUSSION...High pressure peaked across the area today. Many
interior valleys reach into the upper 80s, though some passing upper
level clouds took the edge off heat, especially for the southern
half of the area. A persistent but shallow marine layer has
continued to keep the coast blanketed in clouds.

Low pressure moving into the Central California Coast will help to
ease high pressure over the next couple of days. By Tuesday, high
temperatures in the interior will most likely drop back below 80
degrees. Marine influence will pull more inland, giving some chance
for fog for near coastal valleys. Weak east flow on the back end of
the low pressure will bring better chance for clearing along the
coast, especially on Tuesday and Wednesday.

Ensemble models have started to show better clarity for the forecast
by late weak. Most show high pressure weakly and briefly reforming
around Thursday. A cold front is expected to cross the area around
Friday, helping to drop interior highs into the low and mid 70s for
next weekend. The front will also disrupt and lift any marine layer
that manages to reform on Thursday. Most models still show the front
mostly dry, but now about 20% show very light wetting rain focused
along the North Coast. Weak high pressure is most likely to quickly
rebuild behind the front. Despite the cooler air, there is little
potential (20% or less even for the coldest valleys) for frost
behind the front. /JHW


&&

.AVIATION...High pressure has again enabled a persistent deck of
marine stratus all along shore through the day. Ceilings have barely
lifted to MVFR with just a few breaks expected through the
afternoon. Ceilings will most likely gradually fall back to IFR
conditions overnight though true LIFR conditions remain unlikely.
High pressure will weaken in the coming days. increasing ht
potential for clearer skies. /JHW

&

.MARINE...Moderate to isolated strong north winds have now built
throughout the outer waters, though condition remain calmer closer
to shore, especially north of Cape Mendocino.  Short period seas
have built in response to the winds with waves over 8 feet in the
outer waters and some steep seas up to 6 feet migrating into the
inner waters. Similar winds will persist for the next several days
and even strengthen in the southern outer waters with some near gale
conditions by Tuesday morning. Winds will gradually weaken form
north to south mid to late week as a cold front approaches. Short
period wind waves will continue to dominate the environment
alongside a very minor southwest swell. /JHW


&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
None.
NORTHWEST CALIFORNIA COASTAL WATERS...
     Small Craft Advisory until 9 PM PDT Tuesday for PZZ455-470-
     475.

&&

$$

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