Nicolaus, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

164
FXUS66 KEKA 101132
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
432 AM PDT Thu Apr 10 2025

.SYNOPSIS...Warm and calm weather will continue Thursday with very
light rain or drizzle along the North Coast Thursday afternoon.
Cool and breezy but dry conditions will build Friday through
Saturday. Warm and dry conditions are expected again early next
week.

&&

.DISCUSSION...

KEY MESSAGES:
-Moderate Southerly wind and light rain for Del Norte and northern
 Humboldt Thursday afternoon. Warm and dry elsewhere.

-Cooler conditions and gusty north wind Friday and Saturday,
 especially near the coast.

-Frost possible in some locations Saturday and Sunday mornings.

WEATHER PATTERN OVERVIEW:
An upper level trough moving into the Pacific Northwest is pushing
the ridge out of the area and bringing some light rain to Del
Norte county and northern Humboldt county. This will bring a mix
of sun and clouds to the rest of the area. Tonight and Friday
temperatures continue to cool as another trough moves into the
Pacific Northwest, although this one looks dry. High temperatures
on Friday will generally range from the mid 50s on the north
coast to the upper 60s in the southern valleys. Breezy northerly
winds will also make things seem even colder, especially along the
north coast. Friday night into Saturday morning the colder
valleys will likely see frost, although it is uncertain on how
widespread this will be. Saturday night into Sunday may be colder
in many of the valley locations and this could allow frost to be
more widespread.

Sunday high pressure starts to build in with warming temperatures
again. Afternoon high temperatures are expected to continue
warming on Monday with highs near 80 in many of the inland
valleys. Tuesday and Wednesday the ridge starts to flatten and it
is expected to start cooling off, but at this point it looks like
it will remain dry. The coast may see a return of low clouds at
times.

FORECAST CONFIDENCE AND DEVIATIONS:
Today the big forecast challenge is how far south the precip will
make it this afternoon and how extensive and thick the cloud cover
will be. The deterministic NAM, GFS and HREF showed measurable
precip slightly farther south than the NBM so used the HREF for
pops instead of the NBM. This brought slight chance pops as far
south as Fortuna. This precip is generally not expected to make it
as far east as Willow Creek. In the higher terrain of Del Norte
county the NBM is showing 70 to 90 percent probability of over
0.25 inches of rain. Lower amounts are expected elsewhere. Inland
areas are otherwise expected to see warm and dry conditions with
highs in the 70s in many of the inland valleys.

Friday and Saturday cooler temperatures are expected and breezy
northwest winds. The forecast challenge here will be the
potential for frost in the valleys. For now it looks like Sunday
morning will be the coldest with many of the inland valleys and
possibly the coastal areas see temperatures drop into the low to
mid 30s. The coldest temperatures aloft are expected to be
Saturday morning. However less clouds and lighter winds are
expected for Sunday morning so this will likely be colder in many
of the valleys. The main question is how much low level moisture
will be around to allow the valleys to radiate out. Sunday and
Monday high temperatures are expected to return to the mid to
upper 80s.

Tuesday and Wednesday the ensemble clusters are starting to show
some differences in the pattern. All of the clusters show some
sort of closed low undercutting the ridge and moving into southern
CA. The discrepancies are mainly in the how strong the ridge
manages to stay. Two the clusters bring precip closer and cooler
temperatures, while the other two keep the ridge firmly in place.
Overall it looks like we are heading into a generally dry pattern.
MKK

&&

.AVIATION...A shallow marine layer has been developing across the
coastal waters and moving near shore overnight as a frontal system
approaches. As result, SCT-BKN at FL003 have been impacting CEC. A
brief period of IFR/LIFR conditions with visibility in mist along
the coastal terminal early this morning. SW winds will steadily
increase as this shortwave and associated surface front approach the
coast. Gusts up to 25 knots are possible at both coastal terminals
as ceilings lift into MVFR/VFR, with very light showers or sprinkles
possible in the afternoon. After 11/11Z, UKI will experience
similarly gusty winds out of the NW at the trailing edge of the
frontal boundary.

&&

.MARINE...A rapid increase southerly winds is expected north of Cape
Mendocino this morning as a frontal system moves through. This will
results in a brief period of moderate to fresh breezes across the
northern waters. In the wake of the front, northerly winds will
quickly develops and a steady increase of winds is forecast tonight
through Saturday morning as the surface pressure gradient tighten.
Widespread strong to near gale breezes are expected by Friday
evening and night, with gale force gusts likely across the outer
waters. A Gale Watch in now in effect for zone 475 (southern outer
waters) from Friday evening to late Saturday night. Gale force wind
gusts are expected to expanded to the northern waters early
Saturday. Steep to very steep and hazardous wind waves around 9 to
11 feet at 9 seconds will build in response Friday night and
Saturday. A small long period southerly swell will moves through
Friday afternoon through the weekend. In addition, a series of mid-
period west-northwest swells will impact the coastal waters through
the next seven days.

&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
None.
NORTHWEST CALIFORNIA COASTAL WATERS...
     Small Craft Advisory from 9 AM this morning to 3 PM PDT
     this afternoon for PZZ450-470.

     Gale Watch from Friday evening through late Saturday night
     for PZZ475.

&&

$$

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For forecast zone information
see the forecast zone map online:
https://www.weather.gov/images/eka/zonemap.png