344
FXUS66 KEKA 112159
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
259 PM PDT Sat Oct 11 2025

.SYNOPSIS...Lingering showers through early evening, followed by
relatively drier weather. Areas of fog and patchy dense fog
possible tonight along the shelter valleys with clear skies and
strong radiational cooling. Cold air aloft will promote near frost
temperatures tonight. A colder, wet storm system is forecast to
arrive early Monday, and will bring widespread rainfall, mountain
snow above 4500-5000 feet, and the potential for thunderstorms.


&&

.DISCUSSION...Patches of light rain showers continue moving
across Del Norte, Humboldt and Trinity counties with pretty weak
returns observed on radar. These lingering showers are expected to
dwindling into early evening as the upper-level low centered over
Oregon continue shift eastward into the Intermountain
West. Resulting in surface winds gradually shifting to north
northwest, with breezy conditions over the higher terrain.

Tonight, areas of fog and patchy dense fog are expected to
developed into Sunday along the shelter valleys with clear skies
and strong radiational cooling. NBM have been consistent with
temperatures dropping to 32-36 F across the coldest interior
valleys in Trinity, northeastern Mendocino and northern Lake
counties. However, uncertainty persists regarding frost conditions
during the next few nights across the interior. For tonight into
Sunday, high dew point values in the mid 30`s to mid 40`s will
preclude frost conditions across the interior valleys in Trinity,
interior Mendocino and Lake counties.

A colder, wet system will drop south toward our area on Sunday
afternoon, and eventually moving overhead Monday into Tuesday.
Generally light rain showers will begin to move over the area
from the north Sunday night into Monday ahead of the frontal
system. Operational deterministic model guidances indicate the
trough evolving into a closed low over OR/WA early Monday. Potential
of heavy amounts of rain increases early Monday into Monday
afternoon as the cold occluded front moves southward over the
area. Colder air aloft will bring increasing instability on Monday,
capable of produce brief heavy downpours, and thunderstorms
potential over the coastal waters and along near shore in
Mendocino County. Total rainfall amounts is forecast to range from
0.8 to 1.5 inches across much of the forecast area from late
Sunday through late Tuesday, with the heaviest amounts up to 2.0
inches over the west- southwest windward facing terrain. Less
amounts are forecast for the Humboldt Coast and Del Norte Coast
with total rainfall from 0.5 to 0.8 inches.

Snow levels levels will start about 5500-6000 feet Sunday night,
before lowering to around 4500-5000 feet Monday morning and
afternoon. Some light mountain snow is expected on Scott Mountain
Pass. Total accumulations over Scott Mtn pass is expected to be
between 2-4" from Monday morning through Monday night. Higher snow
amounts from 5 to 11 inches of snow is expected for higher terrain
in Trinity and northeastern Mendocino counties.

Ensemble model guidance are in a good agreement with a high
pressure building over the area mid to late next week. This will
promote drier and warmer temperatures Thursday and into next
weekend. /ZVS


&&

.AVIATION...18z TAF...Showers have generally diminished through the
start of the day, allowing for skies to generally scatter to VFR or
at worst with MVFR ceilings. Such conditions will remain through the
early evening. After around midnight, there is more uncertainty.
About 35% of models show broken, IFR ceilings around 1200 feet
overnight but the the majority of models suggest skies will stay
around VFR. Regardless there is a strong signal of clearing out to
VFR early Sunday before another round of rain and low clouds
approaches the area later in the day. /JHW


&&

.MARINE...Northerly winds have generally calmed through the day with
short period seas fall in response. At the moment, the sea state is
mostly controlled by a modest. mid period northwest swell up to 7
feet. Northerly winds will begin to increase again early Sunday
morning, mostly for the southern waters where some near gale force
gusts are possible by early afternoon. Steep short period seas will
build over 6 feet in the southern waters through Sunday night, but
the northern waters will stay much more calm. Winds will quickly
calm again as shower move through early Monday with the seas once
again coming to be controlled by a moderate mid period, northwest
swell into mid next week. /JHW


&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
None.
NORTHWEST CALIFORNIA COASTAL WATERS...
     Small Craft Advisory from 11 AM to 11 PM PDT Sunday for
     PZZ455.

     Small Craft Advisory from 2 AM to 11 PM PDT Sunday 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.

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