299
FXUS66 KEKA 292247
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
347 PM PDT Sat Aug 29 2026

.KEY MESSAGES...

* Breezy afternoon winds will elevate fire weather concerns in the
  interior this afternoon.

* Dry, generally mild, seasonable weather continues this weekend.

* Fall-like conditions possible next week with multiple chances of
  precipitation and cooler temperatures.

*Isolated thunderstorms are possible Tuesday or Tuesday night.


&&

.SYNOPSIS...Generally mild, seasonable weather continues across
the area with slightly below normal interior temperatures and
coastal areas seeing overnight stratus. A troughing pattern
continues next week, brining below average temperatures and chances
for precipitation.


&&

.DISCUSSION...The stratus and clouds of any kind fully cleared out
going into the afternoon hours. A weak inversion and breezy
northerly winds will continue this pattern through Sunday, with
ample sunshine expected for weekend activities. Interior
temperatures will nudge higher Sunday as mid level heights briefly
increase ahead of the next trough, which is expected Tuesday.

The stratus will deepen again and persist longer along the coastal
areas Monday ahead of a potent midlevel disturbance. This system has
been inconsistently modeled with a fair amount of instability,
with NBM showing moderate chances for MUCAPE over 150 J/kg and
isolated areas in Trinity County higher than 200. The
inconsistency in global models arises from questions in potential
500-700 mb relative humidity. NBM maintains 10 to 15% chances for
thunderstorms mainly for Trinity County, but perhaps into Del
Norte and Humboldt as well. That solution sounds reasonable at
this time, but there are still large discrepancies and a growing
shot for no activity at all. Regarding fire weather concerns,
models do precipitate moisture to the surface with any potential
shower or thunderstorm, but soundings do look on the drier side
for the described interior areas. The higher instability may
progress through with the forcing associated with the passage of
the dynamic shortwave Tuesday night. Guidance has been trending
wetter Wednesday and less unstable Tuesday however. Regardless, a
much wetter environment will immediately follow the trough.

Confidence is growing on a second colder, wetter system moving into
the Pacific Northwest Wednesday, with additional disturbances to
follow in a well established troughing pattern. The main uncertainty
is how far south this will be positioned, but precipitation
estimates continue to grow, with much of the North Coast at over 50%
chances to receive at least a half inch of rain. Wetting rain
(>0.1") chances are around 70% for the North Coast and around 20-40%
for much of the interior outside Lake County. There are also
moderate to high chances for southerly winds to gusts over 25 mph
Wednesday with the storm system. This is a ways out, so there is
still plenty of time for this pattern to change, but right now signs
are pointing to fall-like conditions. Regardless of precipitation,
temperatures are likely to fall well below normal. Chilly morning
lows in the 30s and 40s are possible for much of the interior.


&&

.AVIATION...Northern California received full clearing
Saturday with a weak inversion and drying northerly winds. Winds
ease overnight. Apart from a small area of weak stratus formation
around Humboldt Bay, the region will remain largely cloud free
through Sunday. Should the stratus form, ceilings at ACV would be
mainly IFR with some LIFR chances after 12Z Sunday. Southerly
transport winds have a small chance of brining the stratus to CEC.
Otherwise, the remaining terminals will remain VFR.


&&

.MARINE...Apart from areas around and south of Point St George,
winds in the inner waters north of Cape Mendocino remain below
advisory level. Gust up to 35 kts can be expected around Cape
Mendocino again Sunday afternoon and evening. An isolated area of
gale strength gusts will expand farther into the southern outer
waters this evening and into Sunday. Steep wind driven seas of 7 to
10 ft will develop as a result, with locally higher amounts in the
southern waters around the cape. These will combine with a long-
period south swell arriving today. The northerlies will begin to
quickly subside Monday as a troughing pattern returns. Seas and
winds look to be quite low for much of next week from the troughing.
A stronger front with a round of increased southerly winds will be
possible around mid next week.


&&

.FIRE WEATHER...Breezy northerly to westerly winds will ease into
the evening when good RH recoveries are forecast. Somewhat lighter
but continued breezy conditions will continue Sunday with low RH in
the twenties to teens. A southerly wind surge will push through the
Sacramento valley Monday, with some potential impacts over northeast
Trinity County with the southerly gusts. Westerly winds will be
gusty on Monday over much of our interior while minimum RH and
overnight recoveries continue to improve.

A potent shortwave trough will bring a chance for mostly dry
lightning, or a mixture of some wetter showers/storms Tuesday or
Tuesday night. The available mid to lower level moisture to fuel
these storms is still largely in question, so have held to a
headline for the threat at this time. There is currently a 10-15
percent chance of the thunderstorm occurrence for mainly Trinity
County Tuesday afternoon. The passage of the shortwave through
Tuesday night may bring additional chances, including outside of
Trinity County. The more moisture rich scenarios bring in higher
level instability, so the situation bears watching at least.
Guidance has been trending wetter Wednesday and less unstable
Tuesday however.

There is second colder system forecast to follow Wednesday and bring
accumulating rainfall over the area. Eastern Trinity County has a
50 to 65 percent chance of a wetting rainfall with this system.
Areas farther northwest will have a good chance of meaningful
accumulating rainfall. Breezy southerly winds are possible
Wednesday, which could be problematic if lightning does occur out
there and little rainfall is recorded. The overall environment
will certainly moisten up however. Additional shots of at least
light rainfall continue through late in the week and potentially
into next weekend with a continued troughing pattern.


&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
None.
NORTHWEST CALIFORNIA COASTAL WATERS...
     Small Craft Advisory from 9 PM this evening to 9 PM PDT
     Sunday for PZZ450.

     Small Craft Advisory until 9 AM PDT Monday for PZZ455-470.

     Small Craft Advisory until 3 PM PDT Monday 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