084
FXUS66 KEKA 122219
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
319 PM PDT Sun May 12 2024

.SYNOPSIS...After brief moderation from a passing trough today,
temperatures will begin trending higher through late next week as
a strong ridge of high pressure builds back in. Temperatures
along the coast will continue to be suppressed by persistent
stratus through Monday. Strengthening northerly winds will create
breezy conditions next week.


&&

.DISCUSSION...Afternoon visible satellite reveals abundant
stratus along and over portions of the coast, with cumulus clouds
popping up over interior Trinity County. There will be a slight
chance for a thunderstorm this afternoon over far eastern Trinity
County. A shortwave trough is passing through the region, and has
been responsible for weakening the persistent ridge. This will only
be short-lived as the Pacific ridge will quickly amplify in the
departure of the trough. The cumulus growth this afternoon is yet
to break the cap, but a stray shower of perhaps a thunderstorm
may develop over E Trinity County into the evening. The passing
trough will deliver a weak frontal boundary which may act to
further enhance forcing over the Yolla Bolly areas and into N
Trinity tomorrow afternoon for another shot of isolated showers or
a thunderstorm; however, available moisture is in question.

Northerly winds will begin increasing on Monday afternoon. The
exposed coastal spots will see some gusts from 20 to 30 mph in the
afternoons, with stronger gusts in coastal Del Norte. As the ridge
strengthens Tuesday, a weak upper low will move into S CA. Similarly
as was seen over the last several days, the combination of features
will create above normal temperatures, including warm advection to
the coast from offshore winds. Inland temperatures in the valleys do
look to to be warmer than what was recently observed, with
widespread low to mid 90s.
/JJW


&&

.AVIATION...IFR coastal stratus capping a deep marine layer is
expected to break out a bit this afternoon with strong diurnal
heating and northerly winds offshore. ACV is most likely to
experience MVFR scattering this afternoon while a persistent eddy
south of Pt Saint George maintains the stratus deck in CEC, although
brief breaks are possible. Otherwise, visibilities should remain
mostly clear through early evening even beneath <1000 ft ceilings.
Deeper inland extent and lowering of marine stratus is expected to
resume around sunset, likely reducing visibilities and ceilings
back to IFR conditions at the coast overnight. Northerly winds
will rapidly increase offshore Monday afternoon as the coastal
pressure gradient tightens, helping disperse coastal stratus as
high pressure builds into the region.


&&

.MARINE...Satellite data beginning to indicate the development of
expansion fans cutting through the marine stratus layer downwind of
southern Oregon and Cape Mendocino. Northerly winds will gradually
increase to small craft criteria in the outer waters overnight into
Monday, initiating wind wave responses to 10-12 feet. Gales and
steep seas are expected to rapidly develop Monday evening through
Tuesday, with gusts exceeding 40 knots through late this week. As 30-
40 knot gusts shift to the northern outer waters late Tuesday into
Wednesday, wave heights are forecasted to reach and potentially
exceed 17 feet. With seas largely driven by local winds, the
southern waters are expected to drop below gales by midweek wile the
inner waters maintain some geographic shielding.


&&

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

     Small Craft Advisory from 3 PM Monday to 9 AM PDT Tuesday
     for PZZ455.

     Small Craft Advisory until 3 PM PDT Monday for PZZ470-475.

     Gale Warning from 3 PM Monday to 3 AM PDT Wednesday for
     PZZ470.

     Gale Warning from 3 PM Monday to 9 AM PDT Tuesday for
     PZZ475.

&&

$$

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