Weather Service Report


016 
FXUS66 KEKA 272257
AFDEKA

Area Forecast Discussion
National Weather Service Eureka CA
357 PM PDT MON JUN 27 2016

.SYNOPSIS...An upper level ridge will continue to bring hot and
dry conditions to interior areas of Northwest California through
Wednesday. A cooling trend will begin on Thursday as a trough
settles over the Pacific Northwest. Seasonable temperatures and
mostly cloudy conditions will persist along much of the coast for
at least the next few days.


&&

.DISCUSSION...The axis of a highly amplified upper-level ridge is
currently situated from Utah to the Yukon, leaving Northwest
California on the western periphery in southwest flow aloft. Dry air
is present over northern California and western Oregon on water
vapor satellite imagery. This dry air is likely indicating
subsidence on the backside of a departing shortwave trough moving
northeast through the Pacific Northwest. Thus cumulus development
over the mountains of Northwest California has been quite limited
today. Along the coast the marine layer inversion has remained
robust with stratus persisting for much of the day. Some
downsloping winds off of southern Oregon and Cape Mendocino have
resulted in erosion of the stratus along the northern Mendocino,
southern Humboldt, and Del Norte coastlines. As temperatures cool
this evening the stratus should expand again north along these
coasts, but increasing northerly winds with building high
pressure off the west coast will likely leave at least some holes
in the stratus in areas of downslope.

Heights will increase slightly on Tuesday across the interior
allowing high temperatures to jump a couple of degrees with many
interior valley locations of Mendocino and Trinity counties pushing
into the lower 100s. Though the ridge is expected to start moving
east on Wednesday as an approaching trough moves into the Pacific
Northwest, heights will likely not fall too much allowing for at
least one more day of 100 degree temperatures across the interior.

Better cooling should begin on Thursday and definitely by Friday as
the trough settles over the west coast. Confidence in this solution
is increasing and this will result in temperatures falling back to
near or slightly above normal late in the week and this weekend.
Additionally, the marine layer will deepen along the coast. It is
possible that enough mixing may occur along the coast to dissipate
much of the coastal cloudiness late in the week or this coming
weekend depending on the exact positioning of the upper trough.
Additionally, if enough moisture can be brought into the region,
the cooler air aloft will have the potential to support convective
development over the interior mountains. Considering the pattern
is not particularly supportive of thunderstorms, only very low
chances for precipitation have been included in the forecast for
Thursday and beyond. /RPA


&&

.AVIATION...IFR to LIFR conditions will persist over the coastal
terminals again tonight. LIFR conditions at KACV and KCEC Tuesday
morning, should give way to marginal IFR conditions Tuesday
afternoon, though confidence is not high due to the weak vertical
mixing across a strong marine inversion. At KUKI, expect clear
skies and VFR conditions to continue through the period.


&&

.MARINE...Northerly winds and short period seas will increase
tonight through Thursday. For tonight, SMALL CRAFT ADVISORIES for
winds and seas remain in effect for the outer waters 10-60nm
offshore and for portions of the inner waters south of Cape
Mendocino. Near GALE conditions are expected on Tuesday with short
period seas expected to reach 10 feet or more Tuesday afternoon and
evening in the outer waters. Northerly winds will approach FULL GALE
Wednesday and Thursday, primarily in the outer waters. Seas around
15 feet or more are expected outside 10nm Wed and Thu. 

Closer to shore and inside 10nm, winds will most likely NOT be as
strong except around Cape Mendocino and Pt St George where gusts
to 40 kt are anticipated. Primary concern for the inner waters
will be the short period wind waves. For that, we hoisted a SMALL
CRAFT ADVISORY for hazardous seas starting Tuesday afternoon and
evening for the inner waters north of Cape Mendocino. If the wind
forecast is correct, seas will reach 11-13 ft Wednesday afternoon
and evening north of Cape Mendo inside 10nm. For that, we issued a
HAZARDOUS SEAS WATCH for large and very steep wind waves.
  
Conditions should lay down Friday into Saturday, though near GALE
conditions and steep waves will probably persist in the waters south
of Cape Mendocino through Sat.


&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
NORTHWEST CALIFORNIA COASTAL WATERS...
     Small Craft Advisory from 4 PM Tuesday to 5 PM PDT Wednesday FOR 
     PZZ450.

     Hazardous Seas Watch from Wednesday afternoon through Thursday 
     evening FOR PZZ450.

     Small Craft Advisory until 9 AM PDT Tuesday FOR PZZ470.

     Gale Warning from 9 AM Tuesday to 9 AM PDT Friday FOR PZZ470.

     Small Craft Advisory until 9 PM PDT Saturday FOR PZZ455.

     Small Craft Advisory until 9 PM PDT this evening FOR PZZ475.

     Gale Warning from 9 PM this evening to 9 PM PDT Saturday FOR 
     PZZ475.

&&

$$

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