Small Craft Advisory 43, NWS Eureka, CA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
257 PM PDT Tue Apr 2 2024

.SYNOPSIS...Wednesday will be a transition day as cooler
temperatures, light rain, and gusty winds move into the area.
Wednesday night through Friday well below normal temperatures and
light rain and snow showers are expected. Cool temperatures and
occasional showers will continue through weekend with a return to
warmer temperatures on Monday.

&&

.DISCUSSION...High pressure continues to bring warm and dry
conditions to the area this afternoon. Stratus developed along
the coast this morning and is now firmly entrenched up and down
the coast. Water vapor satellite is showing a cold front
approaching the area. This cold front is expected to move onshore
Wednesday. Initially this is only expected to bring some light
precip in the warm sector ahead of the front in the north. Areas
in Mendocino and Lake counties farther south are not expected to
see any noticeable precip with this first round. Behind the front
much colder air moves in and northwesterly winds will increase.
Wednesday night and Thursday an unseasonably deep upper level is
expected to drop down along the coast. This will bring much colder
air aloft and some showers. Snow levels may drop to as low 1,500
to 2,000 feet. Current models are showing the highest QPF amounts
in Mendocino and Lake counties with some of the mountains reaching
close to a half inch of QPF. This is only expected to result in a
couple inches of snow in a few locations below 3,000 feet. Most
low elevations are only expected to see an inch or so of snow.  A
winter weather advisory may be needed for Thursday afternoon in
portions of Lake and Mendocino county, but at this point
uncertainty is still high on it. There is also the potential for
some thunderstorms with this very cold air aloft. The best chance
on Thursday is expected to be over the waters where the coldest
air and best instability is. There is also a chance for
thunderstorms in Lake county in the afternoon with the peak
heating of the day. The showers on Thursday may have some small
hail in them, but coverage looks fairly limited at this time. A
secondary round of showers is expected in the interior Friday
afternoon with peak heating, but again little to no accumulation
of snow is expected.

Friday night and early Saturday it look like there is a brief
break in the showers between systems. Temperatures will remain
chilly, especially Friday night. The question is how much cloud
cover will still be in place. If skies clear out the colder spots
in Trinity county could see lows in the mid 20s.

Late Saturday and Sunday another system is expected to bring more
rain and snow to the area. Snow levels are expected to be warmer
with snow levels closer to 4,000 feet. Again precipitation amounts
are expected to be light and only up to an inch of snow is
expected.

&&

.AVIATION...A broad shield of stratus capping a shallow marine layer
continues to inundate the coastal terminals in variable IFR/LIFR
conditions this afternoon. Light westerly flow will gradually turn
northwest, however microscale eddies observed on satellite offshore
indicate that minor flow reversals are possible, especially south of
coastal headlands. Daytime heating may still break up the stratus
deck to MVFR in some locations over the next few hours, but low
overcast ceilings should quickly return this evening. UKI remains
clear and dry with variable winds, well out of reach of the marine
layer. Light N/NW flow will continue overnight into Wednesday as a
weak front approaches the NorCal coast. Light precipitation is
slated to begin early Wednesday morning, followed by elevated wind
gusts developing along a thermal gradient as colder air fills in
behind the front. While visibilities should improve, coastal stratus
will struggle to disperse before Wednesday evening.

&&

.MARINE...Winds and seas continue to subside beneath a ridge of
high pressure, while the sea state is largely dominated by a mid-
period NW swell slowly decaying in the waters. Northerly winds
will develop an expansion fan downwind of Cape Mendocino tonight
into Wednesday as a weak frontal boundary approaches the region.
Wind wave response will generate small craft conditions for the
southern outer waters before subsiding late Wednesday into
Thursday. A large, near-shore generated mid-period swell is
expected to fill in late Thursday as a strong surface low dives
south along the central CA coast. Alongside near gale force gusts,
combined seas are currently forecast to approach 15 to 16 feet,
especially in the outer waters.

&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
None.
NORTHWEST CALIFORNIA COASTAL WATERS...
     Small Craft Advisory until 3 PM PDT this afternoon for
     PZZ470.

     Small Craft Advisory until 9 AM PDT Wednesday for PZZ475.

&&

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