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000
FXUS66 KEKA 122126
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
226 PM PDT Fri Apr 12 2024

.SYNOPSIS...Much colder temperatures with periods of rain and
high mountain snow are expected through this weekend. Dry weather
is forecast for next week. Strong and blustery north winds are
forecast for coastal areas early to mid next week while inland
areas warm back up above normal by mid next week.

&&

.DISCUSSION...Stalled frontal boundary offshore will begin to
spread light precipitation across the western most portion of the
forecast area late this afternoon into early this evening. Across
NE Trinty county, daytime heating coupled with some instability,
low buoyant energy and marginal shear profiles may yield a few
late afternoon/early evening thunderstorms. Even after ground
heating ceases, storms may fire up again later tonight as the
500mb cold core edges closer to the coast and SE upslope flow
strengthens. Some cells and rumbles of thunder may drift over NE
Humboldt and Del Norte counties by early Saturday morning.

Otherwise, brunt of incoming precipitation will likely head
southward into southern Humboldt, Mendocino and Lake Counties
tonight into early Saturday morning. Wrap around precipitation
will probably occur on Saturday into early Sunday morning as the
upper level cyclone meanders to the southeast and eventually into
the Great Basin and Desert SW. Overall, precipitation totals over
the weekend are forecast to range from 0.25-0.50in for the north
coast to 1-2 inches for the higher terrain of Mendocino, Lake and
Trinity counties. Heavier precip rates may force snow levels down
to 3K feet Saturday night. Deterministic models and national
blend of models were generally indicating snow levels to be too
high for a winter weather advisory. A dusting of snow on some
higher elevation roads near and above 2500 feet are possible
(<20% chance), but not impactful enough to warrant a winter
weather advisory. It will be much colder and substantially below
normal for mid April in the mountains with early morning minimums
bottoming out in the upper 20s this weekend. Cloud cover and
precip will likely mitigate the risk for frost and freezing
temperatures in the valleys, however.

Early to mid next week, robust north winds are expected to increase
behind the exiting trough as high pressure builds offshore and
surface pressure gradient tighten. Tuesday looks to be the windiest
with strong gusts to 40 mph or more over coastal areas, particularly
the headland and across the King Range. Otherwise, a gradual warming
trend of daytime high temperatures is expected. High temps in
the interior valleys should recover back into the mid 70s by Wed
with possible (20% chance) for lower 80s for the hottest inland
valleys later in the week. DB

&&

.AVIATION...18Z TAF period: A closed surface low is nearing the
coast today. The low will generate mostly light rainfall, with TEMPO
higher precipitation rates that may touch into IFR. VFR to MVFR
conditions will mostly prevail for ACV and CEC. Expected convective
showers and thunderstorms this afternoon over Trinity County are
modeled to potentially pull westward over CEC tonight near 6Z.
Lightning will be possible, but confidence is low on organized
storms making it that far west. Closer to the low, bands of moderate
rainfall rates will propagate onto the coast and toward UKI by early
Saturday morning, lowering the CIGS and VIS to MVFR and perhaps
TEMPO IFR (30%). CIGS will slowly rise back to VFR in UKI towards
the end of this 18Z TAF period while CEC and ACV continue to hold
probabilities for TEMPO MVFR (40%). JJW

&&

.MARINE...Winds continue to weaken this morning as a surface
low approaches and tracks southeast over the offshore waters. Wind
directions are becoming much more variable and chaotic through the
day as multiple small scale eddies spin up nearshore and a front
stalls offshore. Thus, wind directions are forecast to become much
more variable. For the most part, sub-advisory speeds are forecast
(less than 20kt), although brief and localized gusts up to 20 knots
are possible (40%) with mesoscale circulations. Thunderstorms
chances increase over the southern waters closer to the low late
tonight through early Saturday morning (15 to 20%). Some storms will
contain gusty, erratic winds over the souther waters. Waterspout
formation cannot be ruled out in this type of environment, but
better shear will exist along and south of Point Arena.

Probability and coverage for winds gusts of 25 kt or greater
increase on Saturday (30 to 40%), particularly in the southern
waters as the broadening surface low tracks closer to the coast
somewhere near or south of Point Arena. A mid period, NW swell will
also build in on Saturday around 8 to 10 ft. A Small Craft Advisory
has been hoisted for Saturday in the Southern Outer zone to account
for the seas of 10 to 11 feet and some gusts up to 25 kt. A steady
buildup of steep northerly wind waves in conjunction with stronger
northerly wind is anticipated for early next week. TDJ/DB/JJW

&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
None.
NORTHWEST CALIFORNIA COASTAL WATERS...
     Small Craft Advisory from 9 AM to 9 PM PDT Saturday for
     PZZ475.

&&

$$

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