Area Forecast Discussion
Issued by NWS Eureka, CA

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FXUS66 KEKA 031314

National Weather Service Eureka CA
614 AM PDT Wed Jun 3 2020

.SYNOPSIS...Above normal afternoon temperatures are expected for
most of the interior valleys through Thursday. Temperatures will
moderate on Friday, and then plummet this weekend. A chance of
showers and thunderstorms is expected this weekend.


.DISCUSSION...Satellite imagery showed mostly clear skies over land
areas early this morning. A large mass of stratus about 40NM offshore
has been edging closer to the coast through the night. Stratus
may move onshore in fragments as early as this afternoon, per the
HREF and other high resolution models. An offshore flow will likely
erode the leading edge and keep the bulk of the clouds over the

Another warm and sunny day is store for interior NW California
today. High temperatures in the warmest valleys peaked in the
lower to mid 90s yesterday. This is about 15F above normal.
Temperatures are forecast to be warmer today, with highs peaking
near 100F in southern Mendocino and Lake counties. A heat advisory
was issued yesterday based on our experimental heat risk index.
The heat risk for the remainder of the area is forecast to remain
low, though temperatures will remain quite warm and above normal.
Temperatures will begin to diminish on Thu, but remain 10-15F
above normal. Another heat advisory may be necessary.

The heat will moderate more substantially on Friday as an
upstream trough and onshore breezes modify the warm air mass.
More significant cooling is expected for the weekend as an
unseasonably cold air mass drops down from the Gulf of Alaska.
Mountain sites will likely dip to freezing during the early
morning hours this weekend. There is also an outside chance of
morning frost for the valleys of Trinity county Sunday and
Monday. This will depend primarily on the depth and southern
extent of the cool air mass. Skies will probably clear out.

Models and ensemble clusters continue to indicate an upper
trough moving toward the coast on Saturday and then over
the area Sat night and Sunday. This system is probably going the
generate showers for mostly Del Norte and Humboldt counties. With
500mb temperatures plummeting to -20C or less, there is certainly
a potential for storms and pea hail. Highest precip potential and
greatest rain amounts will be along the west slopes of Del Norte
and Humboldt counties. Wet snow will be possible down to 4500 to
5500 feet Sat night.

Showers may linger Sunday. The trend for most of the area is for
drier weather to return early next week. After this cold snap,
temperatures will no doubt slowly increase early next week.


.AVIATION...VFR conditions overnight at the coastal terminals may
give way to mist or haze obscurations Wednesday morning, MVFR flight
conditions are possible.  High clouds are expected throughout the
day along with periods of clear skies as the building high pressure
regime continues. Winds will be light and variable until they
increase in the afternoon from the North with brief gusts.  Light
winds at KUKI and VFR conditions prevailing most of the day. /EYS


.MARINE...Moderate to strong northerly breezes will continue
through early Friday over the outer waters and around Cape Mendocino
and Point Saint George. Occasional gusts to Gale Force in strength
will be also be possible in these areas. Small Craft Advisories are
in place through Thursday night. Conditions are expected to begin to
improve Friday morning. Otherwise, a longer-period SW swell
diminishes as another long-period SW swell arrives today. A mid-
period northwest swell also fills into local waters tonight.  /EYS


CA...Heat Advisory from noon today to 8 PM PDT this evening for

Small Craft Advisory until 9 PM PDT this evening for PZZ450-455.
Small Craft Advisory until 3 AM PDT Friday for PZZ470-475.



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