Area Forecast Discussion
Issued by NWS Eureka, CA

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FXUS66 KEKA 241250

National Weather Service Eureka CA
450 AM PST Tue Jan 24 2017

.SYNOPSIS...High pressure will build toward the coast today
providing dry weather through most of the day on Wednesday. A weak
front will approach the coast late on Wednesday and may produce
some light showers by Wednesday night. Ridging will return later
in the week bringing dry weather through the weekend.


.DISCUSSION...Radar has been showing isolated returns over the
eastern fringes of Trinity county as well as the eastern and far
southern portions of Mendocino county early this morning. The
NAM and HRRR looked to have the best handle on the upslope/wrap
around precip. Both models indicate isolated showers persisting
early this morning, then rapidly decaying shortly after sunrise
as a surface low west of SFO bay slides southward. Except for
some patches of fog and low clouds in the interior valleys and
the residual showers, it is shaping up to be a fine day with
bountiful sunshine.

Upper level ridging offshore will edge closer to the coast
tonight as an upper trough west of 140W pushes eastward. Expect
mostly clear skies with colder overnight temperatures. Some fog
and low clouds will probably develop overnight in the interior

All the models have a weakening front approaching the coast
on Wednesday. Expect we will see an increase in at least high
level clouds during the day on Wed. The latest NAM, GFS and ECMWF
have slowed down the front which will most likely stall and
become stationary offshore before reaching the coast. The front
will meander offshore near the coastline Wed night which may be
the best opportunity for receiving light rain. Expect the boundary
to dissipate by early Thu morning. The NAM and BUFKIT profiles
indicate the boundary layer moistening up Wed night, however the
NAM may be overdone with the shallow push of moist air. If we do
receive any precip, expect it to be fairly light with perhaps a
few hundredths by early Thu morning.

Upper level ridging will spring back up later on Thu and hold
over the region through the weekend. The forecast for the rest of
the period is looking quite dry. It is very typical for the
interior valleys to cloud up and fog up during the night and early
morning hours when skies clear out this time of year. The air
mass does warm up over the weekend and coastal stratus may become
more problematic. The ridge should start to flatten out and
weaken early next week. The GFS and ECMWF bring a front toward
the coast on Tue which will be our next chance of rain.


.AVIATION...Overnight, clearing skies took place as the low
continues to move south towards Baja California. The northeasterly
offshore flow in the low level transported drier air from the
interior into NW California. Crescent City and Arcata airports
reported clear skies early this morning. There were still some
lingering showers and clouds over Ukiah area. However, do expect
the clearing skies to reach them later this morning. All
terminals should see clear skies through the day today. However,
the next system will bring in high clouds to the area terminals
this evening into the overnight hours. Conditions should remain
VFR for all terminals. /RCL


.MARINE...This morning, seas are subsiding as the westerly swell
dissipates. With the lowering wave heights, downgraded the Hazardous
Seas Warning into Small Craft Advisory. The small craft advisory is
good until 9 am this morning for the northern waters, while it is
good until 3 pm this afternoon for the southern waters. Light to
moderate north winds are in store for today as the low pressure area
continues to head south towards Baja California.

Winds will shift back to the south tomorrow as a weak weather front
moves towards NW California. Winds will be fairly light and variable
after that as pressure gradient over the area remains weak.

We will have another significant westerly swell group moving into
the NW California waters Wednesday evening into Thursday. The wave
height is progged to be up to 16 feet. However, the wave period will
be as long as 20 seconds. /RCL


California is finally out of the threat of high surf. The westerly
swell has subsided early this morning. However, we won`t have too
much of a break before the hazardous conditions return to area
beaches. Models are showing sneaker wave potential tomorrow
afternoon into the evening hours, ahead of the next high surf
event. The next high surf event is expected to impact area beaches
late Wednesday night into Thursday. Right now, models are showing
the surf heights around 22 to 25 feet, which is in the range of
high surf advisory. /RCL



Small Craft Advisory until 9 AM PST this morning for PZZ450-470.
Small Craft Advisory until 3 PM PST this afternoon for PZZ455-475.



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