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Area forecast discussion 
National Weather Service Eureka California
345 am PDT Sat Oct 10 2015

Synopsis...another weak front will bring a period of light rain
to the Redwood coast this afternoon and evening...particularly
across del Norte County. A warming and drying trend can be
expected Sunday through much of the work week.


Discussion...the primary weather story over the next 24 hours
will be the approach of another weak and diminishing cold front
this afternoon...which will keep areas north of Cape Mendocino
damp and somewhat cool through this evening. While the fairly
substantial drizzle that developed overnight last night along the
coast has diminished somewhat this morning...patchy drizzle may
redevelop and persist along the coast through the middle morning
ahead of the approaching front. By late this afternoon...the
decaying boundary will reach the coast...bringing with it a period
of light rain primarily across del norte and northern Humboldt
counties. Some of the higher terrain areas of del Norte County may
see as much as a quarter of an inch of rain with the help of
enhanced orographic lift...however most locations should stay
below a tenth of an inch. South of Cape Mendocino...some morning
drizzle along the immediate coast is about all that can be
expected. Some of the higher peaks and ridges will also likely
continue to see periodic gusty southwest winds through this
evening...particularly north of Highway 299...however these winds
should diminish as the front passes by late this evening.

By Sunday...ridging will begin to build aloft and continue to
amplify through the middle of the week...resulting in a warming
and drying trend. As of now...the warmest days of the week will
likely be Tuesday and Wednesday...when 1000-500mb thicknesses will
be greatest. Meanwhile...a slowly retrograding low will move
offshore from Southern California...essentially creating a Rex
block pattern across the western US. Confidence is high regarding
the forecast through Wednesday...but by Thursday uncertainty
increases substantially as this Rex block pattern begins to break
down. At this point...the aforementioned upper low off the coast
will begin to fill in and eject eastward as another larger upper
trough moves closer to the coast from the west. Most previous
model runs kept the track of the departing low too far to the
south to impact our region...however latest runs are a bit
different in bringing it onshore farther to the north. This would
be significant in that it would result in deep southeast flow and
increasing moisture across the region...along with increased upper
forcing. Likewise...that scenario would increase chances for
showers/thunderstorms across northwest California towards the end of the week
should it materialize in this way. Given that this solution is a
significant departure from previous guidance...will opt to keep
the forecast dry until more evidence suggests that the newest
solutions are indeed accurate.


Aviation...conditions will continue to bounce between IFR and
VFR this morning along the coast, but should give way to VFR by
middle morning as an approaching trough causes lifting ceilings. Models
are indicating ceilings falling through the afternoon with possible
low clouds and fog overnight. Interior airports should remain VFR,
outside of those with immediate coastal influence. Bfg


Marine...morning observations show light to moderate winds
across the coastal waters, accompanied by low seas. Winds will
increase slightly through the day as a broad trough slides toward
the coast. The main story remains the large long period southwest
swell arriving today. Buoy 59, 250 nm west of San Francisco is
reporting a SW wave of 10 feet at 15 seconds early this morning.
This is a foot or two under what models are showing, but within
tolerance. We are still expecting SW swell to peak tonight around
10 to 11 feet at 16 seconds. This will create large breaking waves
along the coast and over near shore Shoals, as well as rough
anchorages in south facing harbors. The southwest swell will turn
westerly Saturday afternoon and evening with similar heights and
slightly lower periods. Winds will have a secondary peak on
Saturday as a weak front clips the region. Winds will ease and
turn northerly on Sunday then increase during the first part of
next week. Seas will transition from swells to steep waves as the
northerly waves kick in.

Due to the large swell arriving today, have maintained the marine
weather statement out highlighting threats to near shore mariners.
Also have continued with the small craft advisories for all waters
through early Saturday. A brief lull should occur Saturday morning
before the westerly swell arrives, necessitating another Small
Craft Advisory. Bfg


Eka watches/warnings/advisories...
Northwest California coastal waters...
Small Craft Advisory from 3 am to 3 PM PDT Sunday for pzz450-455.

Small Craft Advisory until 9 PM PDT Sunday for pzz470.

Small Craft Advisory from 9 PM this evening to 9 PM PDT Sunday
for pzz475.



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