Arcata, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

398
FXUS66 KEKA 041111
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
411 AM PDT Fri Apr 4 2025

.SYNOPSIS...Warm, dry, and calm weather will build through the day
on Saturday. Another round of light to moderate rain is expected
late this weekend and into the new week.


&&

.DISCUSSION...

KEY MESSAGES:

-Warm, calm, and dry weather through Saturday: interior highs in
 the upper 70s. Cool temperatures at night: isolated interior
 frost this morning. Chances for frost diminishing for Saturday
 morning

-Moderate south wind and rain return around Sunday: minimal impacts
expected.

WEATHER PATTERN OVERVIEW:A narrow, but slow moving ridge has
continues to build into the region through Saturday. Clear skies
may allow for patchy interior frost early this morning. Though
lows will likely be higher than early yesterday morning, less fog
and cloud cover will likely allow for more efficient cooling. NBM
places a 60 to 80% chance of lows at least as low as 36
throughout northeast Mendocino Country and eastern Humboldt.

Warm, calm, and dry conditions will continue to build through
Saturday. By Saturday, the warmest interior valleys will most
likely see highs between 75 and 79 with little chance (10%) of
highs reaching above 80. Along the coast, northerly wind will
decrease; however, gentle onshore flow and an enhanced inversion
will likely allow for a sporadic, diurnally driven marine layer to
form just along shore.

There is high model confidence that an upper level shortwave will
sweep past the area starting early Sunday. This wave will most
likely bring a short lived period of moderate southerly wind and
rain. Rain will be mostly focused in Humboldt and Del Norte. 0.5
to 2.0 inches of rain is most likely over 24 hours, dependent upon
elevation, with minimal impacts expected. Snow levels will most
likely remain above 4500 feet, greatly limiting any winter
weather impacts. Wind will most likely be similarly moderate with
gusts 20 to 30 mph. Warmer and dryer weather is most likely to
quickly return after the rain.

FORECAST CONFIDENCE AND DEVIATIONS: There is relatively high forecast
confidence for the next 7 days. In the short term, the greatest
uncertainty is related to nighttime frost. The extent of frost
will largely be determined by very localized changes in moisture
and exposure. In either case, the chances of frost will steadily
decrease into the weekend.

There is some uncertainty regarding this weekend`s rain system, and
model guidance has steadily gotten wetter over the past few runs.
That said, there is little potential for much more than a moderate
event. /JHW


&&

.AVIATION...Offshore flow is largely keeping skies clear outside a
few areas of interior valley fog. Models are pointing toward
marginal low level wind shear early this morning, mainly in Trinity
and southern Humboldt counties. Winds aloft ease this afternoon, and
winds generally remain light at all the terminals today. Easing
offshore flow may allow for stratus to develop tonight, but
confidence is low on there being any impacts to terminals. JB


&&

.MARINE...Northerly winds remain breezy this morning south of Cape
Mendocino, but are generally trending downward. By the afternoon,
winds will generally be light to gentle breezes, with a slight
uptick in winds in the late afternoon to 10-15 kts. Seas are
forecast to gradually ease to as low as 2-4 ft this afternoon.
Outside areas of morning fog, conditions remain mild for much of
Saturday.

Saturday evening and overnight, winds begin to turn southerly as a
front approaches. NBM is showing around a 50% probability for wind
gusts exceeding 20 kts, with the highest probabilities north of Cape
Mendocino. Winds remain southerly but ease slightly into Monday,
with generally moderate to fresh breezes forecast. Seas will be
elevated as steep wind waves of 5-8 ft combine with a long-period
swell peaking around 11-14 ft. Southerly winds and elevated seas
continue into early next week, though uncertainties arise on the
extent on any impacts. JB

&&

.BEACH HAZARDS...A long period westerly swell of 10-12 ft at
18 seconds is forecast to fill in Sunday morning. While not a
textbook sneaker wave episode, as a front will bring breezy winds
and shorter periods seas, the scale of the swell presents a moderate
risk of sneaker waves for most of the day Sunday. There is greater
risk along the Mendocino coast, as winds are forecast to be lighter
and large waves could be sneakier. Be cautious visiting steep beaches
and jetties on Sunday and remember to never turn your back on the
ocean! JB


&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
     Beach Hazards Statement from late Saturday night through
     Sunday evening for CAZ101-103-104-109.

     Frost Advisory until 9 AM PDT this morning for CAZ110-111-
     113>115.

NORTHWEST CALIFORNIA COASTAL WATERS...
None.
&&

$$

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