857
FXUS66 KEKA 040815
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
1215 AM PST Sun Jan 4 2026

.SYNOPSIS...Rain showers and coastal flooding continue for Sunday.
Another round of rain and wind is expected Monday before a break
on Tuesday. Light rain and mountain snow are possible again
Wednesday.


&&

.DISCUSSION...The area of low pressure bringing rain and gusty winds
to the area is gradually moving inland early this morning. Lingering
showers and isolated thunderstorms are possible though the early
morning hours. Small streams have mostly crested and have started to
recede as rain rates diminish, however the Mad River is still rising
and may briefly reach Monitor Stage. Snow levels are expected to
drop tonight to around 4,500 to 5,000 feet. This may impact Hwy 3 at
Scott Mountain Summit, but currently isn`t expected to drop low
enough to impact the highest passes along Hwy 36. The heavier rain
is expected to slowly end on today, starting in the northern half of
the area then moving south.

This will be a short lull as, in the afternoon, another weak
boundary is expected to drop down from the north bringing more rain
and wind to mainly Humboldt and Del Norte counties. This is expected
to dissipate late in the evening and overnight. Tonight, the next
system is expected to approach the area and move onshore Monday.
This is expected to bring a period of strong winds to the Mendocino
coast and a lesser extent farther north. Upper-level winds on the
NAM are showing around 40 kt just off the coast. However the GFS is
lighter with the low remaining farther off the coast. A wind
advisory may be needed, but the NBM is only showing a 10 to 20
percent chance of exceeding 40 mph along the Mendocino coast. Higher
elevations of Lake County, including Cobb, do have a 30% chance for
gusts over 40 mph. Rainfall amounts are lower than the recent
systems, with around 1 to 3 inches forecast for most of the area.
The King Range may see an additional 2-3 inches of rain. Snow
levels are expected to be around 3,500 to 4,000 feet with this
system, but confidence is low on this. This could bring notable
snow to Highways 3 and 36. A few snowflakes along the highest
passes on Highway 299 in Trinity County are possible, but little
accumulations are expected.

Tuesday is generally expected to be dry, although there may be some
lingering showers around. Wednesday another system is expected to
move through. This is expected to have lower snow levels, possibly
around 3,000 to 4,000 feet. The amounts look fairly light at this
point, but this will need to be watched as this could affect the
passes along Highway 299 (along with Highways 3 and 36). Rainfall
amounts are also fairly light, with less than a half inch
currently forecast across the area.

Thursday there may be a few lingering showers in the morning, but
high pressure is expected to building in. This is expected to bring
clear skies and dry conditions for Friday and Saturday with night
and morning valley fog in the interior. NBM is showing some higher
probabilities for freezing temperatures starting for Friday and
Saturday morning for much of the area, even coastal areas, but moist
conditions from recent rains are likely to nudge temperatures
upward. JB/MKK


&&

.AVIATION...Another round of heavier showers and gusty winds is
moving across the area bringing lower cigs and vis. This is expected
to start moving out of the area around 12Z, possibly a bit earlier
in the north and later in the south. VFR conditions are expected
through much of the day with lighter winds. Then in the afternoon
another round of showers is expected to spread south across the area
bringing some MVFR conditions. These are expected to diminish just
in time for another rain overnight. MKK


&&

.MARINE...Southerly winds will continue to diminish this morning
before increasing slightly this afternoon with another area of low
pressure bringing 30 kt winds to the southern waters. A westerly
swell has started to build into the waters to around 8 to 10 feet at
15 seconds. This may peak around 10 to 12 feet at 12 seconds Sunday
morning.

Sunday night another area of low pressure is expected to bring more
gusty winds to mainly the southern waters. Again it looks like gusts
to 30 kt are likely. There is quite a bit of uncertainty in the
track of this low and therefore the wind fields. Monday afternoon
and overnight high pressure starts to build in and northerly winds
start to build into the area.  Tuesday night and Wednesday winds are
expected to diminish briefly as a little system moves by the area.
Northerly winds are expected to continue through much of the week.
MKK


&&

.HYDROLOGY...An atmospheric river will bring a prolonged moderate
to heavy rainfall this weekend into early next week. This will bring
increased risk for urban and small stream flooding as well as rock
and landslides across the forecast area through Monday. WPC
continues to have our area in a "Marginal Risk" for excessive
rainfall today through Monday. Small streams around Humboldt Bay are
either peaking or starting to recede, however some may struggle to
drain into the bay with the high tides. This could impact areas just
upstream from the mouth of the Elk River, Jacoby Creek and any other
small creeks that drain into the bay.

Main stem rivers will also likely rise sharply and will need to be
monitored for possible flood stage exceedance. At this point, latest
forecast of CNRFC indicates the mainstem rivers remaining below
flood stage. There is less than a 10 percent chance of any of the
rivers exceeding flood stage. The Mad River at Arcata may exceed
monitor stage and there is a 40 percent chance the Eel River at
Fernbridge will exceed monitor stage. MKK/ZVS


&&

.COASTAL FLOODING...High tides and minor to moderate coastal
flooding are expected again on Sunday, however they are not
expected to be as high as today. Astronomical high tides are 8.5
at the North Spit whereas today they were 8.7 feet above MLLW.
The storm surge model is showing around 1 foot of surge again and
that has been running a half a foot too low. So, overall the
tides could approach 10 feet making it similar to Friday`s tides.
Flooding around the bay will be compounded by small streams not
being able to drain into the bay at high tide. Monday tides
continue to come down, but there could still be some minor coastal
flooding with water levels possibly exceeding 9 feet still.

Outside of Humboldt Bay tides are expected to be high again with
nearly a foot of surge above the astronomical tides. This will be
lower than today, but off the Mendocino coast there is 12 foot
wave at 14 seconds that could bring some higher wave runups and
could possibly worsen impacts. MKK


&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
     High Wind Warning until 4 AM PST early this morning for
     CAZ101-102.

     Flood Watch through Monday afternoon for CAZ101-102.

     Coastal Flood Advisory from 10 AM this morning to 2 PM PST
     this afternoon for CAZ101-104-109.

     Flood Watch through this evening for CAZ103>106-108>115.

     Coastal Flood Warning from 10 AM this morning to 2 PM PST
     this afternoon for CAZ103.

     High Wind Warning until 7 AM PST this morning for CAZ104.

     Winter Storm Warning until 10 AM PST Monday for CAZ107.

NORTHWEST CALIFORNIA COASTAL WATERS...
     Gale Warning until 3 AM PST early this morning for PZZ450-
     470.

     Hazardous Seas Watch until 9 AM PST this morning for PZZ455-
     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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