Area Forecast Discussion
Issued by NWS Eureka, CA

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000
FXUS66 KEKA 161118
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
418 AM PDT Thu Aug 16 2018

.SYNOPSIS...Dry weather will continue for the foreseeable future.
Temperatures will heat up more this weekend especially for
interior areas. After a fairly cloudy and cool week, somewhat
warmer and sunnier weather is expected at the coast this weekend
as well.

&&

.DISCUSSION...As of 4AM satellite imagery shows an expansive
marine layer along the coasts and river valleys of northwest
California. An upper level trough is projected to swing over the
Pacific Northwest today, which may help mix out the marine layer.
Confidence isn`t terribly high in this for today since the area
profiler confirms the deep marine layer. This weekend, and in
particular Saturday, may have a better chance for clearing skies
as offshore winds look likely. With the potential for clearing skies Saturday
afternoon, highs could make it to near 70 degrees for those at the
immediate coast.

Farther inland, an upper level ridge building on Saturday will
bring warming conditions. Highs will make it to near 100 for some
of the hotter inland valleys of Trinty and Mendocino counties,
while other areas experience the 80s and 90s. Unfortunately, these
areas will also continue to deal with quite a bit of smoke from
the Carr Fire and Mendocino Complex, especially close to those
fires in eastern Mendocino and Trinity Counties. The Natchez Fire
and fires in Oregon are also adding to layers of haze aloft.

The forecast will remain dry for northwest California through
next week. Fortunately temperatures should stay mainly below 100
even for the hotter inland valley spots next week. Medium-range
model guidance indicates enough upper-level troughiness over the
Pacific Northwest to keep the heat dome from really building over
northern California. KR/AAD



&&

.AVIATION...A solid deck of low clouds has been covering coastal
areas and adjacent river valleys through the night. Ceilings have
been mostly between 500 to 1000 feet at the coastal terminals.
IFR ceilings are expected this morning. Daytime heating should give
way to higher ceilings near 1000 feet this afternoon. Sustained IFR
conditions may roll back into the coastal terminals this evening,
however an upper level trough will transition across the area late
tonight. The marine layer should start to deepen resulting in higher
ceilings and reduced chances for vsby obscuration.

The marine layer has not been deep enough to push stratus over the
coastal range into UKI again. The primary forecast problem for KUKI
today will be periodic smoke from nearby wild fires. MVFR or IFR
conditions due to smoke will certainly be possible at UKI again
today. The timing and duration of the smoke are highly uncertain.
The marine layer should deepen tonight. Low ceilings may creep into
UKI from the NW by early Friday morning as a weak trough aloft moves
over the area.


&&

.MARINE...Northerlies will increase a tad today, however winds
will still remain fairly light and well below criteria for an
advisory today. Seas have been under 5 feet with a mix bag of
dominant periods ranging from 8 to 15 seconds. Seas will remain
around 5 ft or less through today with a combination of short period
N to NW wind waves, long period NW swell and smaller long period SW
swell.

Seas will deteriorate late tonight through Friday as wind waves grow
offshore in response to strengthening north winds. An advisory for
small craft has been hoisted for the outer waters. North winds are
expected to increase Friday and steep seas will eventually start to
impact the inner waters. An advisory for hazardous seas will need to
be considered.

Steep seas from 11 to 13 feet are expected Friday night and remain
near those levels on Saturday. A warning for seas will need to be
considered for the outer waters. The coverage of wind gusts around
35 kt does not appear to be sufficient to warrant a gale warning at
this time.

Near steady state conditions are anticipated for Sunday. The GFS and
ECMWF indicate a diminishing trend in winds for Monday and Tuesday.


&&

.FIRE WEATHER...A thermal trough is expected to develop along the
coast today. This will aid in the development of an offshore flow
regime, with northeasterly ridgetop winds potentially gusting up
to 25 mph across interior Del Norte County tonight. This will
likely be accompanied by only modest recoveries in relative
humidity. This may be a concern for the Natchez Fire and other
fires in southern Oregon. At the very least, smoke from these
fires will likely drift over much of Del Norte, and perhaps even into
northern Humboldt County heading into Saturday. Additionally, hot
temperatures and low relative humidity is forecast this weekend
across the inland valleys, with high temperatures approaching 100.


&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...None.
NORTHWEST CALIFORNIA COASTAL WATERS...Small Craft Advisory from 2 AM Friday to 3 AM PDT Sunday for
     PZZ470-475.

&&

$$

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