Area Forecast Discussion
Issued by NWS Eureka, CA

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FXUS66 KEKA 252132

National Weather Service Eureka CA
232 PM PDT Mon Oct 25 2021

.SYNOPSIS...Scattered showers will spread east across northwest
California through Wednesday. Warmer and drier conditions are then
expected on Thursday, followed by additional shower development on
Friday and Saturday.


.DISCUSSION...Onshore deep-layer westerlies combined with
afternoon surface heating/destabilization was aiding in the
development of isolated post frontal shower development over the
interior mountains/ridges of northwest California. Shower
development is forecast to become more widespread across both
coastal and inland areas during Tuesday as a frontal wave moves
across the region. Rainfall associated with the front will be
beneficial in nature. Otherwise, drier weather will become
probable during mid week. In addition, low-level winds are
forecast to veer to northerly during Thursday, which will be a
flow regime supportive of warmer temperatures, particularly across
inland valleys, where highs in the 70s are expected.

Non-zero rain chances re-enter the region on Friday and Saturday
as a weak upper wave meanders over the region. However, any
rainfall occurring with that feature is currently forecast to be
very light.



.AVIATION...Through today, isolated vicinity showers became more
scattered in coverage. CIGS held to mostly MVFR, while VIS briefly
came down to IFR with some of the better precipitation rates.
Overnight, showers will become more consolidated in coverage to
more steady light rain at times, and CIGS will favor IFR. Similar
conditions will be for KUKI, but delayed to early tomorrow
morning. Southeast winds will pick up overnight as well, and
become gusty at the surface. A stronger jet of south winds aloft
will briefly clip coastal terminals by early tomorrow morning, up
to 45kts near 2000 feet AGL, providing enough LLWS for placement
in the TAFS.


.MARINE...West swell peaked around 30 feet at 17 seconds last
night. The swell has steadily subsided to around 20 feet this
afternoon. Even though swell heights will slowly decay during the
next 36 hours, seas will become steeper as swell periods decrease.
Also, short period wind waves will build north of Cape Mendo as
southerly winds increase with the approach of a front. A low
duration (2 to 4 hours) gale is possible north of Cape Mendo
during the morning. Seas will lay down some Wednesday morning,
however a reinforcing westerly swell will build by the evening and
seas will become elevated again. Potential for strong northerlies
will increase across the outer waters by Friday evening.


.HYDROLOGY...Heavy rainfall is not expected during the next seven
days. Area rivers will continue to recede as a result.


.BEACH HAZARDS...A west swell peaked around 30 feet at 17 seconds
last night. The swell has since subsided to around 20 ft at 17
seconds this afternoon and should continue on a general downward
trend this evening and overnight. To maintain consistent messaging
and coordination with neighboring offices, we will continue with
the surf warning through this evening.


     High Surf Warning until 11 PM PDT this evening for CAZ101-

     Hazardous Seas Warning until 9 AM PDT Tuesday for PZZ450-



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