Area Forecast Discussion
Issued by NWS Eureka, CA

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000
FXUS66 KEKA 232344
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
344 PM PST Sun Feb 23 2020

.SYNOPSIS...In the wake of a weak cold front, skies will clear
tonight, followed by some valley fog. High pressure will return
for the work week with dry and mild weather. Cooler weather will
arrive with a chance of showers next weekend.

&&

.DISCUSSION...After some occasional light showers today, rainfall
amounts are ending up close to forecast values. We have seen
totals mainly in the trace to 0.05 inch range along the coastal
plain, with local amounts over a quarter inch in the mountains of
Del Norte County. With our unimpressive cold front passing through
this afternoon, leftover light showers have become primarily
restricted to the inland hills and coastal mountains of Humboldt
and Del Norte Counties. Lingering low-level moisture and onshore
flow in the wake of the front will keep clouds hanging around even
back to the coast for awhile longer. However, with clearing
evident just offshore and drier air set to filter in, we will see
some more breaks heading into this evening, especially toward
Crescent City, and may even get a decent sunset around Humboldt
Bay. Meanwhile most of Mendocino and Trinity counties saw a sunny
day today, albeit cooler than the last few. Expect clearing skies
for most of our region overnight, though some river valley fog
will likely develop by morning.

Aside from a foggy start in the inland river valleys, expect a
mostly sunny day on Monday for northwest California. High
temperatures will begin to moderate across the interior as high
pressure builds in, but the coast and mountains will remain a bit
cooler. Low temps Monday and Tuesday will be frosty inland from
the immediate coast, with some sub-freezing temps likely in the
valleys of Trinity County. North to northwesterly breezes will be
found along our coast especially during the afternoon hours at
exposed headlands. These breezes will gradually abate through
midweek, while inland temperatures continue to warm well above
late February averages. Low to mid 70s will be common in the
valleys, with some high temps even reaching into the upper 70s
in southern Mendocino county late week. Some of our more renowned
model guidance points toward some low 60s reaching the immediate coast
Thursday and Friday. However, there are also some hints of
coastal stratus development those days, which would keep high
temps cooler. In any case, it will be a mild and dry week as a
strong ridge of high pressure builds over the West Coast.

There is increasing support from ensemble guidance and now the
operational runs of the GFS and ECMWF for a trough to drop in from
the northwest next weekend. We may yet have a chance for some
light rainfall before February is out. However, the overall
pattern as well as the guidance argues for just light rainfall,
probably from a tenth to as much as a half-inch over next
weekend. In any case, cooler and cloudier weather will accompany
this trough, which will be a noticeable change particularly for
inland areas, following a warm work week. /AAD

&&

.AVIATION...Flying conditions slowly deteriorated this morning in
the northern half of the CWA as a weak front approached the
coast. Light rain and MVFR to short-lived IFR ceilings developed
and should lift later this afternoon as this front moves onshore
and dissipates. VFR conditions are then expected overnight through
tomorrow morning. /TDJ

&&

.MARINE...A weak front moved through the waters today with
moderate north winds redeveloping this afternoon in its wake.
Additionally a large northwest swell will build into the waters with
sea heights reaching 12-14 feet overnight into Monday. The swell
will subside Monday night into Tuesday but steep northerly waves
will develop as the north winds increase. Thus, small craft
advisories returning this evening that currently expire early
Tuesday morning as the swell subsides may need to be extended
depending on model trends. The north winds are forecast to persist
through the remainder of the week, though they should decrease in
strength over time. /RPA&TDJ

&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...None.
NORTHWEST CALIFORNIA COASTAL WATERS...Small Craft Advisory from
      7 PM this evening to 3 AM PST Tuesday for PZZ450-470.

     Small Craft Advisory from 1 AM Monday to 3 AM PST Tuesday for
     PZZ455-475.

&&

$$

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