Area Forecast Discussion
Issued by NWS Eureka, CA

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FXUS66 KEKA 161213

National Weather Service Eureka CA
413 AM PST Mon Jan 16 2017

.SYNOPSIS...High pressure will maintain dry weather through
tonight. A series of storms will generate periods of rain and
mountain snow around mid week. Wet and stormy weather will last
through the weekend.


.DISCUSSION...Today will be the last full day of dry weather.
Occasional high level clouds will move over an upper level ridge
parked offshore the Pacific Northwest coast. Also, patches of fog
and low clouds in the interior valleys have formed during the
night. It will probably take the better part of the morning for
the low clouds to burn off completely.

Most of the forecast area will continue to see dry weather on
Tuesday as the ridge axis shifts southeastward and weakens. There
will be a fair amount of cloud cover as an upper level trough
digs toward the west coast. Light rain will be possible in the
late afternoon, primarily in the northern most part of the
forecast area. A long fetch of 1+ inch precipitable water was
being entrained into the offshore trough. The long moisture stream
will initially be north of the forecast area on Tuesday. It will
start to sag southward on Wednesday as a sruface cold front
approaches the coast. The highest rain rates, up to an 1 inch in 6
hours, will be Wednesday afternoon and evening as the front moves
through. The widespread rain should ease up and change over to
numerous or scattered showers by Thu as cold air aloft and
instability arrives. Shallow low topped convection will be
possible on Thu as well. For now will hold off on adding storms
to the forecast for Thu. Snow levels will fall to around 3500 to
4000 feet on Thu. An advisory will need to be considered for
elevations above 3500 feet, primarily for South Fork Mountain

Another storm will rapidly follow Thu night into Fri. The latest
GFS and ECMWF have trended warmer with this storm. Snow levels
will probably be above 3500 feet Thu night when the bulk of precip
falls. A third storm will impact the region with more wind, rain
and mountain snow over the weekend.

By far, the main threat this week looks to be huge surf. Large
long period westerly swell will impact the coast on Friday. Swell
on the order of 25 to 30 feet with breakers in excess of 35 feet
will be possible on Friday. The exact magnitude of the swell is
not certain. Standby for more information and possible warnings
or advisories.


.AVIATION...VFR to IFR conditions and light winds to calm conditions will
continue at KCEC and KUKI through the early morning. The lower conditions
will be due to reduced ceilings and/or visibilities due to stratus and patchy
fog. VFR to MVFR conditions will continue at KACV through the early morning
with the lower conditions due to reduced ceilings with lower visibilities
occurring at times. VFR conditions and light winds will prevail at KCEC, KACV
and KUKI later this morning through this evening.


.MARINE...Light to moderate winds will continue across the waters through
tonight. The pressure gradient will increase across the area on Tuesday
generated by a strong low pressure system off the southwestern Canadian coast.
This will increase the winds and seas across the waters Tuesday. Elevated winds
and seas will persist across the waters Tuesday through this weekend as a series
of cold fronts move through the region. Small craft advisories will be in effect
across the outer waters Tuesday morning through Wednesday morning. A gale warning
is likely across the outer waters on Wednesday due to increasing winds. A Small
craft advisory will be in effect across the northern near shore waters Tuesday
morning through Thursday morning and will likely be extended through this weekend.
A small craft advisory will be in effect across the southern near shore waters
Tuesday evening Through Thursday morning and will likely be extended through
this weekend. Seas will increase more across all the waters on



AM Tuesday to 9 AM PST Thursday for PZZ450. Small Craft Advisory
from 9 AM Tuesday to 3 AM PST Wednesday for PZZ470-475. Small
Craft Advisory from 9 PM Tuesday to 9 AM PST Thursday for PZZ455.



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