Mendocino, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

780
FXUS66 KEKA 072211
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
311 PM PDT Mon Apr 7 2025

.SYNOPSIS...Occasional light rain showers continue today. Additional light rain
and breezy south wind in Del Norte Tuesday. Warm and dry weather
returns to the interior midweek.


&&

.DISCUSSION...Scattered rain showers are still moving onshore this
afternoon, mostly affecting Del Norte, Humboldt and Trinity County.
Total rainfall ranges from 0.25 to 0.75 inches over the last 12
hours, highest in northern Humboldt and Del Norte. A broad upper
trough sitting over the PNW will lend favor to largely zonal flow
across northern CA, sending a steady stream of cloud cover into the
region. Showers are expected to diminish slightly this afternoon and
evening, with cooler temperatures in the upper 30`s likely in the
northern valleys of Mendocino and Lake, including Round Valley and
Laytonville; probabilities seem to just miss the mark on
Frost/Freeze products, especially with lingering cloud cover.

Another shortwave riding within the trough will sweep through
Tuesday morning, bringing another round of showers and gusty winds
to the north coast. HREF QPF probabilities are still rather modest
with about 20 to 40% chance of >0.20 inches from 5 PM this evening
through Tuesday afternoon, confined to far northern Del Norte, with
lighter showers possible in northern and coastal Humboldt. The
heaviest rainfall and southerly wind gusts will be between 8AM and
12PM Tuesday. Hi-res models have been consistently forecasting 20 to
30 mph gusts developing along a frontal boundary stemming from a
strong surface low off the WA/OR coast. 925mb winds approach 40
knots in the outer waters of the OR/CA border, while higher winds
stay mostly north of our CWA. HREF probabilities for gusts >35 mph
are around 50% for the far northern Del Norte coast, steeply
dropping off at 40 mph. The greatest impacts will likely be minimal
and once again confined to Del Norte County, but breezy conditions
with gusts 15 to 25 mph are likely across the Humboldt coast and
elevated ridges in the coast ranges north of Cape Mendocino.

As mentioned in the previous discussion, broad ridging will build
Wednesday, bringing warmer temperatures and clearing skies to the
area, especially interior valleys. NBM probabilities are trending a
bit lower, with about 30 to 50% for temperatures >75 degrees within
interior valleys, including Ukiah, Covelo and Hayfork. Mid to long
range models are favoring Thursday as the slightly warmer day,
potentially allowing highs to tick up into the upper 70`s and low
60`s along the coast. Otherwise, with high pressure over the eastern
Pacific, a strong marine layer is likely to form beneath light NNW
flow, dampening the high temperature forecast for coastal areas.

Another weak shortwave will move through late Thursday into Friday,
very similar in nature to Tuesday - minor precip and wind gusts
confined to northern counties. Some cluster ensembles have light
troughing indicators for the PNW this weekend, but may only impact
WA/OR as a strong high pressure center continues dominating the
eastern Pacific.


&&

.AVIATION...A cold front band moved across the North Coast by mid-morning,
accompanied by gusty winds and (mostly) -RA/-SHWRS. Cigs were
generally MVFR but occasionally IFR around Humboldt Bay-ACV airport.
By 9am, ACV`s air terminal was reporting IFR Cig/Vis as plenty of
diverse low clouds covered Del Norte and Humboldt Counties. A
pronounced wind shift (0830-0900 LSt) was recorded at CEC and ACV
airports...and NWS Eureka. Areas of low clouds and shallow
precipitation will hover along the North Coast today before
conditions start to improve to VFR. Winds will decrease into the
late afternoon and evening. Gusty conditions will return with the
approach of another trough line after 08/06z as previously
mentioned. Impactful Cig/Vis can be expected in the mid-late
morning. Inland areas: uncertainty in model guidance leaves the
possibility for some fog and MVFR conditions in the mid-morning at
UKI. /TA



&&

.MARINE...Southwest winds briefly diminish this afternoon following a
frontal passage. Wave heights will remain elevated in the outer
waters through Tuesday as a large long period NW swell continues
to decay. Winds will quickly rebound tonight into Tuesday morning
as another upper trough approaches the region. Small craft
advisory conditions will persist in the northern outer waters
Tuesday afternoon in response to frontal winds gusting 20 to 30
knots, keeping wave heights 9 to 10 feet. The sea state will
significantly diminish mid-week beneath building high pressure.
Another shortwave will arrive late Thursday into Friday, enhancing
southerly winds in the northern waters - currently, gusts look to
remain near or below advisory levels. Long term, persistent
northerlies and steep wind waves could dominate the sea state this
weekend as high pressure sits over the eastern Pacific.


&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
None.
NORTHWEST CALIFORNIA COASTAL WATERS...
     Small Craft Advisory until 3 PM PDT this afternoon for
     PZZ450-455.

     Small Craft Advisory until 4 PM PDT Tuesday for PZZ470.

     Small Craft Advisory until 3 AM PDT Tuesday for PZZ475.

&&

$$

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