Arcata, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

307
FXUS66 KEKA 021238
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
504 AM PDT Wed Apr 2 2025

.SYNOPSIS...Few isolated showers continue to diminish as a cold
upper low progresses south. Clearing and drying will allow for
some colder overnight lows. A sharp warmup with building high
pressure can be expected for the end of the week, followed by some
rain chances.


&&

.DISCUSSION...The area of low pressure continues off to the south
of Northwestern California with some straggling showers continuing
to diminish into this afternoon. The usual post frontal
deterrents for cold overnight lows, such as lingering cloud cover
and moisture, and chance for developing fog, frost and freeze
conditions have and will occur in some of our inland locations
where the growing season has officially begun. A Frost Advisory
and Freeze Warning have been hoisted for interior Mendocino and
Lake County through mid morning. There are also frosty
temperatures of 36 degrees or less forecast for interior Humboldt,
but confidence is lower there for the reasons outlined above.
Growing season has begun for interior Humboldt today, so it will
be closely watched, and a Frost Advisory may be warranted if
drying and clearing occurs sooner.

Confidence is higher for cooler temps and frost/freeze conditions tonight
and into Thursday morning. There is more confidence for interior
Mendocino and Lake counties to reach freezing/frost conditions
overnight and into Thursday morning. As a result, a Freeze
Warning has been issued for Northern interior Mendocino. Then,
also, a frost advisory has been issued for Southern interior
Mendocino and Southern Lake.

A stout area of high pressure will then amplify into the area by
Friday and through the weekend. Temperatures will warm up nicely
in response. The apex of the warming will be Saturday, when low to
mid 60s are forecast for the coast, and low to mid 70s for the
interior valleys. Rain chances increase late Saturday and Sunday
from a clipping weather system. If cloudcover arrives earlier on
Saturday, temperatures may be held down a bit.

Currently, rainfall looks light with this system, with the
probability of 24 hour rainfall over 0.50 inch 40-60% for the
Humboldt through Del Norte Sunday and Monday.There may be some
increased southerly winds, especially if the low takes a more
southerly track. There are currently low probabilities for wind
gusts over 25 mph. /JJW


&&

.AVIATION...Winds effectively decoupled overnight, keeping all
terminals VFR overnight beneath broken mid-level ceilings and light
NE flow. LLWS is still prevalent for UKI as winds aloft remain
elevated through the morning hours - otherwise, the Russian River
Valley has so far avoided low level clouds/fog. Hi-res models are
coinciding well with an observable line of scattered showers
approaching the coast on the backside of a cold upper trough.
Periods of gusty rain showers are possible at both CEC and ACV
through midday, moving from north to south. Widespread gusty NW
winds are expected to resume this afternoon as a high pressure ridge
builds into the eastern Pacific, tightening the coastal pressure
gradient. High probabilities for gusts 10 to 20 knots expected at
all terminals through this evening, with locally higher gusts
lingering a bit longer at CEC. Drier northerly flow will keep the
marine layer at bay through the end of the week.


&&

.MARINE...Small craft conditions with steep northerly wind waves
continue across the waters as a NW swell decays. Moderate northerly
breezes will keep seas elevated through the end of the week as a
high pressure ridge builds into the eastern Pacific. Probabilities
for gusts 25 to 30 knots will remain highest in the outer waters and
downwind of Cape Mendocino - NBM has a 20 to 40% chance of gusts
reaching 34 knots on Thursday evening. Diurnal increases in winds
will likely push elevated seas further into the inner waters each
afternoon. Winds and seas diminish significantly by Friday and
Saturday. Potential for another frontal system to arrive Sunday as a
large long period swell fills into the waters. Previously calm
conditions may pose a sneaker wave threat as this swell arrives.


&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
     Freeze Warning until 9 AM PDT this morning for CAZ110-111-
     114.

     Freeze Warning from 2 AM to 9 AM PDT Thursday for CAZ110-
     111.

     Frost Advisory from 2 AM to 9 AM PDT Thursday for CAZ112-
     113-115.

     Frost Advisory until 9 AM PDT this morning for CAZ113-115.

NORTHWEST CALIFORNIA COASTAL WATERS...
     Small Craft Advisory until 9 AM PDT this morning for PZZ450.

     Small Craft Advisory until 9 AM PDT Thursday for PZZ455.

     Small Craft Advisory until 3 AM PDT Friday for PZZ470-475.

&&

$$

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https://www.weather.gov/images/eka/zonemap.png