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000
FXUS66 KEKA 161122
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
422 AM PDT Tue Apr 16 2024

.SYNOPSIS...Gusty northerly winds expected in coastal areas through
mid-week as high pressure builds into the region. Increasing
temperatures beneath clearing skies will allow interior valleys to
approach 80 degrees by late week. Marine stratus expected to return
in the latter half of the week as northerly winds subside.



&&

.DISCUSSION...Skies are mostly clear across the CWA as a high pressure
ridge builds into the region. The broken stratus deck spanning the
interior will hinder widespread fog/frost development early this
morning before mixing out with diurnal heating. WAA ahead of the
building ridge will allow daytime temperatures to steadily climb
into the 70`s within interior valleys for the next several days -
NBM has 50-60% probabilities of temperatures exceeding 75 degrees in
interior Mendocino and Lake counties by Wednesday afternoon. Nightly
offshore flow will also help to dry out the interior as adiabatic
warming lowers RH values. Meanwhile, a recurring pattern of strong
northerlies will remain prevalent offshore through midweek - this
should prevent marine stratus from inundating the coastline and
encourage diurnal heating. As a result, NBM indicates a high
probability of coastal temperatures nearing 60 degrees by Wednesday
afternoon.

Long range models are indicating a minor breakdown in the high
pressure ridge late this week, causing northerly winds to subside
and shift further offshore. This will give the marine layer a chance
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, further strengthening the marine
inversion. With this in mind, NBM coastal high temperatures are
being tamped down to account for potential coastal stratus. Interior
RH values will likely decrease below 50%, while valley temperatures
in Mendocino and Lake counties have high probabilities of reaching
80 degrees, especially on Thursday. While probabilities are slightly
lower for interior Humboldt and Trinity, temperatures are still
expected to rise into the mid to upper 70`s.

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



&&

.AVIATION...Latest space pictures show interior valley fog in
Humboldt, the Eel Delta, western Trinity and SW Mendocino
counties...as well as just west of KACV. These clouds may
intermittently impact the terminal early this morning, then are
expected to mix out this morning. Gusty offshore winds overnight
have kept Del Norte clear. VFR is expected to continue across much
of the region through the rest of the TAF period. Low clouds may
form once again tonight in the Eel River Delta, although this is
expected to be less expansive than it is this morning.


&&

.MARINE...It is highly probable that Gale strength wind gusts have
developed across portions of the outer zones overnight, and these
are forecast to spread south this morning. Expansion fans south of
Cape Mendocino and Point Saint George will bring areas (<50%
coverage) of Gales into the inners, mainly in the afternoons and
evenings through Wednesday. The 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.




&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
None.
NORTHWEST CALIFORNIA COASTAL WATERS...
     Small Craft Advisory until 3 PM PDT this afternoon for
     PZZ450.

     Hazardous Seas Warning from 3 PM this afternoon to 3 AM PDT
     Wednesday for PZZ450.

     Small Craft Advisory until 9 AM PDT Wednesday for PZZ455.

     Gale Warning until 9 PM PDT Wednesday for PZZ470.

     Small Craft Advisory until 9 AM PDT this morning for PZZ475.

     Gale Warning from 9 AM this morning to 3 PM PDT Wednesday
     for PZZ475.

&&

$$

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For forecast zone information
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https://www.weather.gov/images/eka/zonemap.png