Ruth, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

497
FXUS66 KEKA 151152
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
452 AM PDT Tue Apr 15 2025

.SYNOPSIS...A return of the marine clouds and fog will bring
cooler temperatures to the coastal and near coastal areas.
The cooling trend is expected to continue through Thursday. There
is a slight chance for thunderstorms over the interior mountains
Tuesday and Wednesday. Sunny skies and breezy conditions are
expected late in the week with continued temperatures in the 60s
and 70s.

&&

.DISCUSSION...An upper level low off southern CA undercutting the
high pressure is bringing some changes to the weather pattern.
This has brought a flow reversal along the coast and pushed
coastal north onto the northern CA coast. This brought widespread
stratus to the Mendocino coast yesterday evening and it is now
spreading onto the Humboldt and Del Norte coast. Some of this fog
is dense. Stratus is also moving from Sonoma county north into
Mendocino county. Clouds are expected to clear back to the coast
by late morning or early afternoon. However the marine air is
still expected to keep temperatures 5 to 10 degrees cooler than
yesterday in the near coastal areas such as Ukiah, Willits,
Garberville, etc.

This low pressure is also pushing some mid level moisture
northward. This will bring the potential for some thunderstorms
over the interior mountains. Currently it looks like the best
chances will be over the Yolla Bolla mountains for this afternoon
and evening. However there is also a slight chance in the Trinity
horn. There is still some uncertainty on how far north the
moisture will make it. Most of the models show Weaverville PWATS
less than 0.6 inches. Farther south in Ukiah PWATS are higher with
the ensemble average closer to 0.8 inches. However the marine
influence is expected to keep Ukiah cooler and limit the
thunderstorm potential. This leaves the Yolla Bollas in
northeastern Mendocino, northern Lake and southeastern Trinity
counties as the most likely to see a thunderstorm or two. Mid
level lapse rates are high, over 8 c/km in most areas so this
should help any storms that form to grow quickly. However with
wind shear of around 15 kt the storms are expected to only pulse
up and down and be tied more to the terrain.

Wednesday the models have come into better agreement on a dry
weather system dropping down from the and bringing dry air to the
area by the afternoon. This is especially true in the north where
PWATS drop below a half inch by the afternoon. Mid level lapse
rates also drop through the afternoon to around or less than 7
c.km. Still have a slight chance of thunderstorms in for Wednesday
afternoon, but confidence is low on this.

Thursday and Friday additional shortwaves moving down from the
north bring cooler air and breezy winds on Thursday. Overnight
these will become more offshore and are expected to keep the
coastal clouds off the coast. Some frost is possible overnight in
the colder spots, this will need to be watched.

For the weekend high pressure is expected to build over the area
once again on Saturday, however the ensembles clusters are
showing different solutions as to how strong this will get. Then
on Sunday most of the clusters are showing a shortwave moving down
from the northwest and bringing some cooler air. At this point it
still looks dry. Monday looks to be similar with possibly slightly
cooler temperatures as well. MKK

&&

.AVIATION...Stratus has blanketed the coastal waters and adjacent
land areas this morning as a southerly reversals developed nearshore
south of Cape Mendocino. LIFR conditions with visibility in FG/BR
are expected to persist along the coastal terminals through late
morning/early afternoon. IFR ceilings possible for both coastal
terminals by this afternoon, but HREF model guidance suggest a brief
period of SCT clouds in the afternoon. LIFR conditions are expected
to return for ACV and CEC after 16/00Z. Winds will become WSW around
7 to 12kts after 18Z along the coast, then SSE up to 5 kts after
16/03Z.

UKI...Light southerly winds have been pushing the stratus northward
from Santa Rosa. As result, LIFR ceilings have developed at UKI
early this morning. Otherwise, conditions are expected to improve to
VFR after 16Z. However, mid to high clouds will continue to spread
across the area. Surface winds from S around 5-12kt today, becoming
lighter tonight.

&&

.MARINE...Northerly winds continue to increase across the northern
outer waters and portions of the southern outer waters this morning,
with moderate to strong breezes. Meanwhile, a light to gentle
reversal and southerly winds have developed south of Cape
Mendocino with a cut-off trough. Seas will remain steep and
hazardous for small craft across the outer waters today.

Winds will increase to strong to near-gale force sustained winds
tonight into Wednesday across the outer waters, with the strongest
winds north of Cape Mendocino. Northerlies are expected to continue
strengthening on Wednesday. These strong gusts will likely migrate
into northern nearshore waters, before expanding across the
southern outer waters Wednesday evening. Gale Force gusts up to 40
kts are forecast for the northern outer waters on Wednesday.
Locally gale force gusts are likely around Pt St George Wednesday
afternoon and evening. Very steep and hazardous wind waves
reaching 12 to 15 will develop as a result of these winds,
persisting through Thursday.

&&

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

     Hazardous Seas Watch from Wednesday afternoon through late
     Wednesday night for PZZ450-455-475.

     Small Craft Advisory until midnight PDT tonight for PZZ470.

     Gale Warning from midnight tonight to 3 AM PDT Thursday for
     PZZ470.

     Small Craft Advisory until 3 PM PDT Wednesday for PZZ475.

&&

$$

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