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Area forecast discussion 
National Weather Service Eureka California
404 am PDT Thursday Oct 8 2015

Synopsis...dry and seasonable weather conditions will prevail
across northwest California through Friday as high pressure aloft
remains over the region. A weak trough will brush far northwest
California with the possibility for a few showers on Saturday.


Discussion...variable high cloudiness has been moving over the
forecast area through the night. The high clouds have been
thinning and scattering out through the night for some Star light
to shine through at times. Satellite imagery also showed no low
stratus clouds with all surface stations reporting clear skies
all night. Nam12 time-height cross sections indicate fairly low
rh's below 3kft through Friday morning...then a steady ramp up in
lower level humidity and moist air Friday afternoon through
Saturday morning. Thus suspect we will start to see a return of
the gray skies Friday night. Otherwise mild weather conditions
with partly sunny to partly cloudy skies are expected for the
coast today through much of Friday.

The latest model guidance (nam12 and gfs) continue to remain on
track with a frontal boundary stalling out offshore on Friday
before reaching the coast. Going into Friday night the guidance
has been somewhat more inconsistent and indecisive. The GFS and
ecwmf were dry...while the nam12 continues to be the outlier
with some spotty light precipitation. With the nam12 showing a ramp up
in lower level moisture...the coast may see some spotty drizzle
overnight. We are not expecting much in the way of precipitation
here...perhaps a hundredth or two. On Saturday a low amplitude
short-wave trough will move into the Pacific northwest (washington
and oregon) and brush far northwest California with the
possibility of some light showers. The best chances continue to be
over del Norte County where a few hundredth's to possibly a tenth
may accrue by early Sat evening. Farther southward any showers will
be fairly light...brief and probably not much more than a hundredth
or two if any at all. Overall it is not looking like a major rain
out or wet weekend. A ridge near the surface and aloft will begin
build Sat night into early Sunday. Sunday is shaping up to be a fine
day after the typical morning low clouds burn off. The models
indicate light offshore flow in the morning on there may
not be much if any low clouds at the coast. For now will be
optimistic and hit the stratus forecast lightly on Sunday.

Models continue to be in good agreement with a Rex block taking
shape early next week and holding this pattern through middle week.
Dry and warmer weather conditions are expected as a ridge both at
the surface and aloft remains over northwest California. For now
just went with the statistical and consensus guidance which has
maximum temperatures increasing into the lower 90s in the interior
during this time frame. At the coast the surface flow pattern does
not resemble one that would bring a substantial warm up. Suspect
there will be some coastal stratus during the night and morning
hours which should clear out with daytime heating and mixing.


Aviation...high pressure sinking to the south and low pressure
drifting toward the region should keep ceilings lifted enough to
maintain VFR across northwest cal today. Do not expect any restrictions
today into tonight. Bfg


Marine...light winds will continue through the day as a weak
pressure gradient remains over the coastal waters. A change in the
pattern will occur this evening and overnight as broad low pressure
over the Gulf of Alaska absorbs Post tropical storm oho and shifts
slightly toward the West Coast. This will cause southerly winds to
increase slightly, moreover, it will bring the first large swell of
the season. Expect SW swell to build into the region on Friday with
heights as high as 12 feet at about 15 to 17 seconds. The increase in
southerly winds will be short lived, confined to tonight and early
Friday. However, the swell will linger into the weekend. The main
concern around this swell will creating rough anchorages and Harbor
that are exposed to the south and southwest. As this swell passes
and a weak cold front clips the region, Post frontal swell will take
over. Swell will transition from SW to west over the weekend, but
remain elevated with a long period. Shoaling will remain a threat
with these long period swells through the weekend. Long period waves
can cause significant set behavior in breaking waves over near shore
Shoals. With the threat of long period large swells through the
weekend, mariners are encouraged to exercise extreme caution if
heading out on the waters. Shoreline Fishers and ab divers may want
to delay activities until the swells pass. A brief lull in
conditions will occur Monday before northerly winds develop causing
steepening waves Tuesday into Wednesday. Models are indicating a
longer lived lull middle to late next week. Bfg


Eka watches/warnings/advisories...
Northwest California coastal waters...
Small Craft Advisory from 3 PM Friday to 9 am PDT Saturday
for pzz410-450-455-475.

Small Craft Advisory from 3 am Friday to 9 am PDT Saturday
for pzz470.



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