Gale Watch 14, NWS Eureka, CA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
325 PM PDT Thu Mar 28 2024

.SYNOPSIS...Showers activity will continue to wind down this
afternoon and evening. A second round of wind and gusty showers
will hit the southern half of the area on Friday with cool and
clearing conditions through the weekend.

&&

.DISCUSSION...Post-frontal scattered showers and isolated
thunderstorms continue moving east-northeast across the area this
afternoon, especially over areas farther north of Mendocino
County. Snowfall amounts as of 3500 feet have been very light feet
on highway 36 this afternoon. Showers activity are expected to
wind down late this afternoon and evening.

IR satellite imagery depicts an amplifying upper level
trough/deepening cutoff low stalled over the NEPAC this
afternoon, while a secondary and stronger Pacific Storm rotate
around the cutoff. This secondary low system will continue to move
southward and quickly strengthen as approaches the California
Coast Friday afternoon, absorbing the current cutoff low. Showers
will begin to increase in coverage Friday morning becoming
stratiform precipitation Friday afternoon along the warm sector of
the low. Moderate to locally heavy periods of rainfall is
forecast for the southern portion of the CWA Friday afternoon and
evening. While light precipitation is expected for the rest of
the forecast area. Additional rainfall ranging from 0.3 to 1 inch
is most likely from this system, with heavier amounts farther
southern portion of Mendocino and Lake County. Wind turning east
through the event will generally focus rain along higher terrain
and rain shadow lower elevation areas such as Clear Lake itself.

Increasing east-southeast winds are expected Friday afternoon and
evening, mainly focused over Mendocino and Lake counties. Gusts
from 30 to around 40 mph are are expected over the coastal
headland and exposed ridges as result. However, with the
easterly winds may aid in funneling gusty winds in Lake County.
The National Blend of Models (NBM) 90-95th percentile (high end)
indicates gusts around 45mph in Lake County, with strongest winds
over the higher elevation. Continued evaluation is needed for
Wind Advisory criteria. /ZVS

.LONG TERM... (FROM PREVIOUS DISCUSSION) Cold air will advect
alongside the low as it travels south, brining chilly nights in
the 40s through the weekend. That said, stubbornly cloudy skies
will inhibit widespread frost and valley fog formation until at
least Sunday morning, when the coldest and clearest conditions are
most likely. As the low moves east, it will help enhance the
pressure gradient with high pressure building over the east
Pacific. This will allow for strong northerly wind right along
shore and just offshore Sunday into early next week. Thanks to the
wind's consistency, NBM already show high confidence in northerly
wind gusts of 25 to 35 mph hitting shore Sunday. That said,
generally stable conditions and weak winds aloft (associated with
the high pressure) will most likely inhibit any wind advisory
level gusts (45 mph).

Model ensembles show high confidence (80%) of at least a couple days
of high pressure dominated warm and clear days early next week with
strong onshore flow in exposed areas. There is much more
divergence by mid next week, however. Most (80%) of cluster ensemble
members show a trough moving onshore sometime between next Wednesday
and Friday, but the exact strength and impact of the trough varies
widely. Only about 30% of ensemble members show the trough produce
impactful rain and wind. (more than 1 inch and gusts over 45 mph)
/JHW

&&

.AVIATION...Post-frontal, on-going showers have continued to have lingering
impacts at the Taf sites today. CEC to experience gusty surface
winds today plus VCTS in the mid-late morning. Cig/Vis generally
remained VFR. ACV continued with breezy winds and occasional bouts
of MVFR from mid-late morning. UKI, through early afternoon,
remained a little "Topsy-Turvy" as numerous showers moved across
the terminal. Conditions briefly dropped into IFR. Basically,
shower activity will taper through the evening...especially north
of Cape Mendocino. Offshore, another low pressure system, and
associated frontal boundaries, will dip south and have a greater
impact over Mendocino and UKI Friday morning; lowering Cig/Vis can
be expected with substantial precipitation. /TA

&&

.MARINE...A steep mid-period swell peaked this afternoon around 15
feet at 14 to 15 seconds. Combined with southerly wind wave energy,
significant wave heights reached 18-19 feet. Winds and seas will
diminish overnight before a shortwave drives a progressive surface
low south along the CA coast. The trajectory of this low will
dictate the enhancement and orientation of winds heading into the
weekend.  Winds will turn southeasterly and increase in the southern
waters early Friday afternoon, likely generating a brief period of
gale gusts in the outer waters. Winds will gradually turn to the
east/northeast Friday night into Saturday as the low dips south of
Point Arena, with wave heights persisting at 8-10 feet throughout. A
tightening pressure gradient between the northeast quadrant of the
low and an offshore ridge building into the waters will gradually
generate increasing northerly winds on Saturday. Saturday night into
Sunday holds the greatest chance of gale or potentially storm force
gusts, beginning in the northern waters and extending south. Wind
waves are expected to respond quickly with wave heights 15-17 feet
possible early Sunday morning. Winds and seas will likely remain
elevated through the weekend before a reprieve to start next week.

&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
None.
NORTHWEST CALIFORNIA COASTAL WATERS...
     Small Craft Advisory until 9 PM PDT Friday for PZZ450-470-
     475.

     Small Craft Advisory until 3 PM PDT Friday for PZZ455.

&&

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For forecast zone information
see the forecast zone map online:
https://www.weather.gov/images/eka/zonemap.png