857
FXUS66 KEKA 262159
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
259 PM PDT Thu Sep 26 2024

.SYNOPSIS...Hot and dry conditions will persist through early
next week for inland areas of northwest California. Coastal areas
will remain more seasonal with overnight cloudiness and afternoon
scattering.

&&

.DISCUSSION...Quiet and dry weather conditions resumed today with
mild temperatures along the coast and warmer temperatures inland.
Stratus brought low visibilities to many parts of the coast today
but conditions slowly improved as clouds eroded away from valleys
and scattered out parts of the coast.

Ensemble guidance is showing building 500 mb heights and warming 850
mb temperatures on Friday and then cooling 850 mb temperatures on
Sunday as a dry, upper level trough impacts the region. Overall,
this means warm and dry weather is forecast to continue into the
weekend. Above normal temperatures across inland areas are predicted
to reach the 90s on Friday and Saturday and then decrease by a
few degrees on Sunday. The heat risk looks to be minor at this
time as chances for exceeding 100 degrees over the weekend has
diminished. Coastal temperatures will remain seasonal through the
weekend. Increasing northerly winds across the coastal waters will
help promote stratus development, and some patchy fog, for parts
of the north coast this weekend with afternoon scattering
expected.

Moving into early next week, high pressure will amplify leading to
another round of hot and dry weather across the interior valleys.
Inland temperatures could approach 100 degrees on Monday and Tuesday
with NBM showing a 45% chance for greater than 100 degrees for Ukiah
on Tuesday. Additionally, overnight recoveries will be poor. On
Monday night into Tuesday morning relative humidity could be low as
20% across interior valleys and possibly in the teens over some Lake
County ridges. The surface pressure pattern will also cause offshore
flow to develop early next week which could bring coastal
temperatures near 70 degrees. Unlike the last offshore event, this
one will lack deep layer easterlies and marine air may hinder the
warming for coastal areas.

Looking into the very long range, ensembles are showing a decreasing
500 mb height trend for late next week with cluster analysis
indicating an upper level trough to enter the pattern. But both are
also showing large spread and model variability this far in advance,
which is typical for this time of year. Thus, impactful rain for
northwest California is still uncertain but it does tell us the
atmosphere is wanting to switch up the pattern. /KMZ

&&

.AVIATION...Along the Mendocino, Humboldt and Del Norte coasts,
persistent-clingy marine stratus has impacted Taf sites and local
airfields (mostly negatively) into the start of afternoon. (The
area offshore appeared to be a little disorganized as mention in
the previous discussion). Cig/Vis were consistently LIFR/IFR
through afternoon, with pockets of Binovc along the immediate
shoreline by 1 PM. Several morning pilot reports (pireps) reported
cloud tops 011-014 (1,100 to 1.400 feet). The marine layer was
deep enough to extend into Humboldt`s local river valleys and to
also squeeze out a little juice over Humboldt Bay. Into Friday,
guidance continues to maintain the stratus layer along the coast
in the morning then some clearing following a weak system that
will clip the region. Increased winds aloft tonight/overnight may
trigger the potential for LLWS at CEC and ACV overnight. /TA

&&

.MARINE...Northerlies around 20-25 kt persist south of Cape Mendo
tonight then begin to spread into the northern waters Friday.
Northerlies will strengthen Friday with potential for gale force
gusts and large steep waves over 10 feet - mostly over the outer
waters. Elevated northerly winds and large steep seas over 10 ft are
forecast to continue through the weekend and into next week. Highest
seas are forecast outside 20NM. DB/JM

&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
None.
NORTHWEST CALIFORNIA COASTAL WATERS...
     Small Craft Advisory from 9 PM Friday to 9 PM PDT Saturday
     for PZZ450.

     Small Craft Advisory until 5 PM PDT Friday for PZZ455.

     Small Craft Advisory from 3 PM Friday to 9 PM PDT Saturday
     for PZZ470.

     Small Craft Advisory until 9 PM PDT Saturday for PZZ475.

&&

$$

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