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000
FXUS66 KEKA 092157
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
257 PM PDT Tue Apr 9 2024

.SYNOPSIS...Warm, summer-like weather will continue through mid
week. A weak storm system will bring cooler weather, rain, and wind
late week into the weekend.


&&

.DISCUSSION...High pressure has continued to spread across the area.
With warm valley temperatures in the 70s and generally dry air all
across the area. A well defined marine layer with coastal stratus
blanketed the coast this morning but has since mixed out except near
Klamath.

High pressure will continue to build tomorrow bringing a distinctly
summer like character to the weather. Many interior valleys will
reach the low 80s though NBM shows essentially 0% chance of any
location reaching 90. Hot interior temperatures will continue to aid
in the formation of a coastal marine layer overnight. The marine
layer, however, should stay weak enough to allow for afternoon
clearing under the increasingly strong spring sunshine.

Winter hasen`t totally released it grip, however, with all cluster
ensemble members showing a cutoff low pressure system impacting the
coast Thursday into the weekend. This low will drop temperatures
back into the 50s and low 60s by Friday. Instability will arrive
ahead of low Thursday as southerly flow aloft builds in moist
unstable air. This could allow for diurnal afternoon thunderstorms
to form (10 to 30% chance) mostly around the rim of the Sacramento
Valley and over the Siskiyou Mountains. The exact timing of the low
(which remains uncertain) and its exact alignment with peak solar
heating will likely determine the final probability of thunderstorms.

A cold front moving onshore around Saturday will then bring much
more widespread rain all along the coast with gusty southerly flow
near the surface helping to enhance the usual topographically forced
areas. NBM currently show most likely rainfall of 0.3 to 0.7 inches
across the area by the end of the weekend. Only a very weak and
modified cold air mass is associated with this system which will
most likely keep snow levels above 3000 feet. This will limit the
general risk of snow to high mountain peaks with only minimal small
hail potential. /JHW


&&

.AVIATION...Summer-like conditions will continue for this TAF
period. Winds along the coastal sites are gusting up to 25 mph at
KCEC and KACV out of the northwest. Interior areas can expect mostly
clear skies and VFR conditions through the TAF period. Coastal
stratus and temporary periods of mist is forecast to affect the
coast again by early tomorrow morning.


&&

.MARINE...High pressure has entered into the region and has
produced breezy northerlies across the waters. Winds up to 20 knots
are possible in the northern waters today, and up to 30 knots in the
southern waters, with locally higher values in the lee of Cape
Mendocino. This pattern will continue through Friday. The sea state
will consist of steep northerly wind waves and a series of mid-to-
late northwesterly swells, with the highest combined significant
wave heights Wednesday and Thursday of up to 12 feet. A low pressure
system entering the waters on Thursday and Friday will disrupt this
pattern.


&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
None.
NORTHWEST CALIFORNIA COASTAL WATERS...
     Small Craft Advisory until 9 AM PDT Thursday for PZZ450-470.

     Small Craft Advisory until 9 AM PDT Thursday for PZZ455-475.

&&

$$

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