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000
FXUS66 KEKA 151145
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
445 AM PDT Mon Apr 15 2024

.SYNOPSIS...Gusty northerly winds expected through mid-week as high
pressure builds into the CA coast. Increasing temperatures beneath
clearing skies will allow interior valleys to reach into the upper
70`s. Marine stratus expected to return in the latter half of the
week as northerly winds subside.


&&

.DISCUSSION...An inverted ridge of high pressure will continue to
build into the CA coast as an upper cutoff low progresses east into
the Great Basin. Low stratus and scattered high cirrus are still
being observed across the region as a trailing shortwave dips into
the PNW - this should prevent widespread valley frost/fog, but with
the BL still saturated with residual moisture, scattered fog and
low ceilings are expected this morning throughout the CWA.
Northerly winds will steadily increase today along the tightening
pressure gradient between the building ridge and departing low.
Gusts 25 to 30 mph are likely by early this afternoon along
exposed headlands and coastlines from Crescent City down to Point
Arena.

WAA ahead of the building Pacific High promises a return to summer-
like conditions for the start to this week. Temperatures are
expected to steadily climb beneath mostly clear skies, with highs
likely to reach into the mid-70`s within interior valleys by
Wednesday. Nightly offshore flow will also help to dry out the
interior as RH values decrease. Meanwhile, a recurring pattern of
strong northerlies will remain prevalent offshore through midweek -
this should prevent marine stratus from completely inundating the
coastline and encourage diurnal heating. NBM indicates a high
probability of coastal temperatures reaching 60 degrees by Wednesday
afternoon.

As northerlies subside and shift to westerly onshore flow late this
week, the marine layer will likely be able to deepen and spread
further inland beneath broad high pressure subsidence, dampening
daytime warming. Model soundings and long-range deterministic models
indicate strong low to mid level warming and drying Thursday and
Friday. Interior RH values are forecast to decrease below 50%, while
NBM has 60-70% probabilities for valley temperatures to exceed 75
degrees.

Long range model clusters begin to show the Pacific ridge eroding
into more zonal flow by next weekend. Currently, no major storm
systems are forecast for the next 7-10 days.


&&

.AVIATION...Broken MVFR stratus covers most of the region this
morning. Conditions are forecast to improve across the region later
this morning as northerlies increase and daytime heating mixes out
the stratus. Northerlies continue to strengthen into this afternoon,
with blustery winds expected at the coastal terminals. Low cloud
cover and mist will probably redevelop across the interior valleys
this evening, and possibly in the Humboldt Bay region should a small-
scale nearshore southerly reversal set up...confidence is low as to
whether this pocket of moisture will push far enough north to impact
KACV, if it even develops. VFR is expected tonight in Del norte as
offshores keep skies clear.


&&

.MARINE...Northerly winds will steadily increase through
Tuesday afternoon. Gale gusts are expected late this afternoon into
the evening hours downwind of Cape Mendo and Cape Blanco. Forecast
coverage of gale gusts is below 50%, but increases during the
evening per the HREF probabilities Monday evening, especially for
the northern outer waters. Coverage appears sufficient through the
night to warrant a marginal gale. Supercritical flow with expansion
fans both downwind of Cape Mendo and Cape Blanco will probably
continue to yield localized regions or narrow corridors of gusts to
35-40kt Tue and Wed. Steep northerly short period waves will build
in response to the steady state northerlies the next 3 days, peaking
to around 13 ft on Wed over the outer waters.

Axis of strongest northerlies and largest seas will most likely
shift westward toward the latter portion of the week and conditions
will ease up and improve - especially for the inner waters. DB


&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
None.
NORTHWEST CALIFORNIA COASTAL WATERS...
     Small Craft Advisory until 9 AM PDT Wednesday for PZZ450-
     455.

     Small Craft Advisory until 9 PM PDT this evening for PZZ470.

     Gale Warning from 9 PM this evening to 5 PM PDT Wednesday
     for PZZ470.

     Small Craft Advisory until 9 AM PDT Tuesday for PZZ475.

     Gale Warning from 9 AM Tuesday to 5 PM PDT Wednesday for
     PZZ475.

&&

$$

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