688
FXUS66 KEKA 010711
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
1211 AM PDT Sat Nov 1 2025

.SYNOPSIS...Sneaker wave threat today through early Sunday morning.
Light rain possible in Del Norte and northern Humboldt this
afternoon and evening, while dry weather prevails elsewhere.
Stronger storm possible Wednesday, with the potential for strong
south winds, heavy rainfall, and urban/small stream flooding. Higher
than normal astronomical tides Tuesday through Saturday.


&&

.KEY MESSAGES...


- Sneaker wave threat for the coast today through early Sunday
  morning.

- Chance of light rainfall over Del Norte and northern Humboldt on
  this afternoon and evening.

- Active weather returns next week, with the potential for strong
  south winds, heavy rainfall, urban/small stream flooding.

- Higher than normal tides next week, with storm surge promoting
  coastal flooding in Humboldt Bay, Crescent City, and possibly areas
  on the Mendocino Coast.


&&

.DISCUSSION...High clouds have started to stream in as high pressure
begins to weaken and a weak cold front approaches the area. A chance
for light rain arrives by the afternoon or evening hours in Humboldt
and Del Norte Counties. Otherwise, impacts are limited to mid to
high clouds across the area and moderated interior temperatures in
the 70s. At the coast, light southerly flow ahead of the front may
actually promote slightly warmer temperatures in the mid 60s before
rain arrives in the late afternoon. High pressure rebuilds
temporarily Sunday, clearing skies. Interior temperatures remains
generally in the 70s, but coastal temperatures may drop down into
the high 50s as winds turn more northerly.

The start of a wetter pattern arrives Monday afternoon as a
shortwave trough dips down into the Pacific Northwest and
northwestern California. There is a fair amount of variability in
this system. Some ensemble members show a surface low forming off
the coast of northern California and moving northwest. Others do not
show any significant surface low forming off the coast. Because of
these differences, the possible precipitation amounts vary greatly.
In Del Norte and northern Humboldt, precipitation amounts range from
1/10 to 3/4 of an inch. The NBM 50th percentile shows 0.25-0.50
inches in Humboldt and Del Norte with much lower amounts elsewhere.

Confidence is increasing of a second, stronger system approaching
the area late Tuesday into Wednesday. Strong southerly wind is
likely ahead of the front Tuesday night into Wednesday as a low-
level jet strengthens off the coast. Models are showing winds at 925
mb (~2000 ft) at around 70 kts right off the coast. These translate
to surface gusts of 40-60 mph over coastal headlands and exposed
ridges. NBM is showing 40-50% probabilities for lower elevations to
see gusts over 40 mph, with much higher probabilities over higher
terrain. Probabilities of over 50 mph drop off to 20% or less
outside of the exposed ridges. However, if the 70+ kt coastal jet is
realized, wind gusts are more likely to be on the higher end of the
range. Significant wind impacts are possible if this trend
continues.

As for precipitation impacts, models are fairly consistent in
showing a period of heavy rain across the area early Wednesday. Much
colder temperatures aloft behind the frontal passage could support
greater instability with heavier rain showers and possibly
thunderstorms continuing Wednesday afternoon and overnight into
Thursday. There is a fairly large spread in precipitation estimates.
Comparing the low end and high end amounts (25th and 75th
percentile) for 48 hour precipitation (4 AM Tuesday to 4 AM
Thursday), Del Norte, Humboldt, and Trinity range from around 1-3
inches, and Mendocino and Lake range from around 0.5-2.0 inches.
Because of the narrow band of moisture, some areas are likely to see
high end amounts while some areas see low end amounts. Details will
become clearer in the coming days. JB


&&

.AVIATION...Periods of stratus could develop for coastal terminals
early Saturday morning, again bringing MVFR to IFR conditions. These
may lift slightly towards the morning hours. Through the day clouds
are expected to lower again in the afternoon as a front brings some
light rain to northern Humboldt and Del Norte counties. Gusty
southerly winds are forecast along the Del Norte as the front
approaches late morning and into the afternoon. Gusty northwesterly
winds may occur around souther Mendocino late afternoon/evening.


&&

.MARINE...The northerly swell is expected to get reinforced and this
is increasing periods back to 14 seconds and heights building
slightly. Farther north the approaching frontal boundary will start
bringing some light southerly winds early Saturday. These southerly
winds are expected to peak in the north on Saturday around 10 to 15
kt. A larger northwest swell is expected to combine with the
existing swell and peak around 10 feet at 16 seconds on Saturday.
There will likely be some set behavior with these waves.

Northerly winds are expected to quickly return Saturday evening and
overnight. These are expected to peak around 20 kt off the coast on
Sunday. The northwest swell is expected to continue to be around 10
feet on Sunday.  Sunday night and Monday the winds drop off quickly
and become southerly again early Monday with another frontal
boundary approaching. This is expected to quickly increase the
southerly winds and has them peaking Monday afternoon or evening
near 20 to 25 kt. Models appear to have trended slightly faster and
stronger with this system.

Tuesday the southerly winds diminish slightly, but remain near 15
kt. The next system is expected to move into the area Tuesday night
and Wednesday. The CMC, ECMWF and GFS all show at least gale force
sustained southerly winds. The CMC and the GFS show storm force
sustained winds. Needless to say this will need to be watched as it
gets closer. MKK


&&

.BEACH HAZARDS...The next swell is expected to arrive this morning.
This could pose a sneaker wave threat. Initially wave periods are
expected to be around 20 seconds with waves building and combining
with the current swell to around 12 to 13 feet at 17 seconds. Winds
will still be southerly and fairly light. This will likely increase
the set behavior and therefore the sneaker wave potential. MKK


&&

.COASTAL FLOODING...Next week astronomical high tides are above 8
feet at the North Spit starting on Wednesday and peak at 8.5 feet
Thursday. Moderate to strong southerly winds are now expected in
this time frame and this will likely cause at least minor coastal
flooding. If the timing lines up with the wind and high tides this
event may end up with water levels near 10 feet at the North Spit
tide gauge. Outside of Humboldt Bay there is the potential for
coastal flooding if the waves end up large. Confidence is low, but
it looks like there may be large waves at this time. MKK


&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
     Beach Hazards Statement from 5 AM PDT early this morning
     through late tonight for CAZ101-103-104-109.

NORTHWEST CALIFORNIA COASTAL WATERS...
     Small Craft Advisory from 8 AM this morning to 3 AM PDT
     Monday for PZZ450.

     Small Craft Advisory from noon today to 3 AM PDT Monday for
     PZZ455-475.

     Small Craft Advisory until 3 AM PDT Monday for PZZ470.

&&

$$

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