Area Forecast Discussion
Issued by NWS Eureka, CA

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FXUS66 KEKA 271624 CCA

National Weather Service Eureka CA
543 AM PST Fri Jan 27 2023

.SYNOPSIS...Dry conditions will persist through Saturday.
Temperatures will begin a cooling trend as a a pair of low
pressure systems will drop southward over the West Coast this
weekend. A slight chance of light rain and some light mountain snow
is forecast for Saturday night into Sunday morning. A colder airmass
will bring below normal temperatures early next week.


.DISCUSSION...The high pressure located over the NE Pacific is
starting to weaken and slowly shifting to the west as an upper
shortwave trough dig southward across the Pacific Northwest. This
has allowed flow at the surface to become more zonal. IR Satellite
imagery shows high level clouds spreading southward through
northern California this morning, while marine layer clouds have
developed and have moved onshore, but are limited to the coastal
waters. The aforementioned upper trough will move into the region
this afternoon and evening, and then exit the area late tonight.
Winds will become breezy north to northwesterly winds in response
during the afternoon, with gusty winds over the exposed coastal
headlands and ridgetops. High temperatures are expected to be 10
to 20 degrees cooler at the coast, and 5 to 10 degrees lower in
the interior compared to yesterday`s reading due to the cooler air
aloft and the marine push. This evening, as the onshore flow
continues to increase the stratus should to expand and push
inland as the low level inversion strengthen. Dry weather
conditions will persists through

A stronger upper shortwave trough will approaches from the north
Saturday evening and into Sunday morning, bringing a slight chance
of light rain to Del Norte and Humboldt counties late Saturday
night and into early Sunday morning. Rainfall amounts are
expected to be light, with less than a tenth of an inch on some
windward facing terrain. Snow levels are anticipated to drop to
about 2000 ft MSL by Saturday night and even further to 1500 ft
MSL by Sunday morning. However, very light or nothing of snow is
anticipated. Otherwise, this trough will provide upper-level
support and reinforcing surge of dry, cool air from north and
northeast. As the upper level trough exit to the south Sunday
evening, the high pressure begin to build back to the West Coast
and tightening the surface pressure promoting gustier winds along
some of the more exposed coastal locations as well as some ridgetops
bordering Lake and northeast Mendocino counties Sunday evening
through Monday monring, but these remains sub- advisory levels.

Temperatures will be significantly cooler on Monday through
Wednesday. ECMWF Extreme Forecast Index (EFI) highlights
temperatures below normal for northern California early next
week. Ensemble models indicating freezing and below freezing
morning temperatures along the coast.


.AVIATION...Clear skies prevailed overnight with just some
MVFR visibilities in haze/mist at KCEC, likely caused by residual
sea spray from subsiding surf. VFR conditions are expected to
continue today after a few patches of ground fog clear out, mainly
near sources of standing water. Winds are expected to remain light
this morning, then gusty northerlies develop this afternoon as a
weak shortwave slides down the coast.


.MARINE...N winds will increase once again on Friday as the first of
two lows moves down the coast from the north. The Small Craft
Advisory will continue through the weekend as the second of these
lows will likely be stronger and tighten the pressure gradient
substantially Saturday night into Sunday. Northerlies may flirt with
Gale Force during this time period and seas will become steep,
particularly in the outer waters. North winds will persist on
Monday, finally decreasing Monday night into Tuesday./RPA&SEC&TDJ


.BEACH HAZARDS...A long period westerly swell around 5 to 7 feet
at 18 to 19 seconds is spreading into the inner coastal waters
this morning. There is a moderate threat of sneaker waves
possible for coastal beaches today. A Beach Hazard Statement
remain in place for all coastal waters through late this afternoon.


     Beach Hazards Statement through this afternoon for CAZ101-

     Small Craft Advisory from 3 PM this afternoon to 3 PM PST
     Sunday for PZZ450-455.

     Small Craft Advisory until 3 PM PST Sunday for PZZ470.

     Small Craft Advisory until 3 PM PST Sunday for PZZ475.



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