FXUS66 KEKA 202230
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
330 PM PDT Mon May 20 2019

.SYNOPSIS...Another Spring storm will generate widespread showers
and high mountain snow above 5500 feet tonight through Tuesday. 
Blustery westerly and northwesterly winds are also expected, 
especially over the exposed higher elevations and mountain peaks. 
Drier weather and brisk northerly winds are expected around mid 
week.

&&

.Short Term...The shortwave ridging over the area brought clear 
skies and dry conditions to the area this afternoon. A frontal 
boundary just off the coast is expected to move onshore this 
evening bringing rain to the area tonight and Tuesday. Rainfall 
amounts are expected be around an inch in most areas with local 
amounts over 2 inches in the mountains of Humboldt and Del Norte 
counties. Farther south and east in Trinity and Mendocino counties
rainfall amounts will be closer to a half inch. Snow levels with 
this system will be around 5,000 to 5,500 feet. Snow amounts will 
be 6 to 12 inches above 5,500 feet. Late tonight there is the 
potential for thunderstorms in Del Norte county. The threat is not
particularly high, but there is over 100 j/kg of cape. This 
threat will continue in the inland areas in the afternoon. These 
thunderstorms are not expected to be strong, but locally heavy 
downpours are possible. 

Tuesday night high pressure starts to build into the area and
breezy northerly winds will pick up along the coast. The showers
will come to an end fairly quickly in the evening. Some frost is 
possible in the interior again, but there may be too much moisture
around to see frost. This will need to be watched as it gets 
closer. MKK

.Long Term...(from prev. discussion)...The spell of wet weather 
and below normal interior temperatures will moderate around mid 
week as the flow aloft amplifies. A large closed low aloft will 
shift to our south and southeast while high pressure builds toward
the west coast. This pressure pattern will be a good SETUP for 
gusty northerly winds at the coast and over the mountain peaks. 
THE BLEND, NAEFS and ECMWF ENS indicate another shortwave trough 
dropping southward over the area next weekend. This shortwave may 
put a damper on the warming and produce additional shower 
activity, primarily over the interior.

&&

.AVIATION...Plenty of low level moisture resulted in widespread 
MVFR Cigs along the coast this morning. Low clouds also expanded 
across much of Mendocino interior including UKI. Several PIREPS 
put most clouds bases above 1200 feet but below 2000 feet. Low 
level moisture (CU/SC) continued into the afternoon with Cigs 
mostly VFR. An influx of higher clouds began to move into the 
region by mid-afternoon. The incoming storm system will began to 
impact the Redwood Coast by late afternoon as prefrontal light 
rain moves ashore and lower Cigs encroach the Del Norte Coast. 
Breezy south winds today will steadily ramp up through the 
evening. A threat of LLWS should be brief from late afternoon 
through early evening.

&&

.MARINE...Winds have become southerly across the waters this
afternoon. Tonight southerly winds will increase slightly to 15 
to 25 kt in the evening just ahead of a weak frontal boundary. The
strongest winds will be north of Cape Mendocino. Later tonight 
behind the front winds will slowly switch to the west, but remain 
around 10 to 20 kt. Tuesday these winds will become northwest and 
increase to 15 to 25 kt. 

Northerlies will continue to increase Wednesday and Thursday with
gale force gusts possible. Winds are expected to start to 
diminish Friday, although confidence is low on exactly how much 
it will diminish at that point. Northerly winds are expected to 
continue over the weekend. They are expected to diminish to around
10 to 20 kt, but confidence is low on this at this point. 

The swell has finally dropped below 10 feet this afternoon. A 
large W swell will build into the waters late tonight and 
Tuesday morning. This swell will be around 14 seconds when it
builds in initially, with combined seas peaking near 20 ft. At
this point it looks like the larger seas will remain in the outer
waters. Have issued a hazardous seas warning for the outer waters
for much of Tuesday. It looks like it may be a fairly brief period
with waves peaking around 20 to 22 feet. Surf heights along the 
NW California coast will approach 20 ft as well, just below High 
Surf Advisory criteria. MKK/SEC

&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...None.
NORTHWEST CALIFORNIA COASTAL WATERS...
Small Craft Advisory until 3 AM PDT Friday for PZZ450.

     Small Craft Advisory until 6 AM PDT Tuesday for PZZ470.

     Hazardous Seas Warning from 6 AM to 9 PM PDT Tuesday for PZZ470-
     475.

     Small Craft Advisory from 9 PM this evening to 3 AM PDT Friday 
     for PZZ455.

     Small Craft Advisory from 9 PM this evening to 6 AM PDT Tuesday 
     for PZZ475.

&&

$$

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