Area Forecast Discussion
Issued by NWS Eureka, CA
FXUS66 KEKA 021241
AREA FORECAST DISCUSSION
National Weather Service Eureka CA
441 AM PST Fri Dec 2 2016
.SYNOPSIS...High pressure will dominate through Saturday bringing
dry weather conditions. A weak front will drop down from the north
on Sunday bringing a chance of rain to the region. Another weak
front is expected on Monday.
.DISCUSSION...A ridge aloft will dominate and provide dry weather
conditions for Northwest California through Saturday. Early
morning temperatures have been in the mid 30s at most locations
where we have a frost advisory in effect. For the most part the
frost advisory has been verifying. The approaching front will
probably send greater amounts of mid and high cloud over the
region tonight. Overnight temperatures will moderate, especially
out toward the coast. Another frost advisory will most likely not
Broad westerly flow aloft will start to sag southward over the
northern most portion of the forecast area on Sunday. The first
in a series of weak shorter wavelength troughs will skirt across
the area by Sunday afternoon and evening providing light rain
amounts. A potentially colder short-wave is expected for Monday
or Monday Night. The precipitation amounts probably will not be
prolific, however the cold nature of this system may bring a
mix bag of wintery weather and low snow levels by Monday night.
The GFS and ECMWF were not in real good synch and confidence is
still not high on the timing. After this wave passes, drier
conditions should return for Tue and Wed.
GFS and ECMWF indicate broad flat ridging developing around mid
week in advance of a potentially warmer...wetter and stronger
frontal system. The models have been all over the place on the
timing...location and duration of the rain. We are probably going
to see light to moderate rain toward the latter portion of the
week, however there is still too much variability in the data to
nail it down. Backed off of the rain potential to reflect less
confidence in the forecast from Wed to Fri.
.AVIATION...VFR conditions are expected to prevail through the
next 24 hours. Aside from some shallow ground fog near the coast,
and patchy inland valley fog, local terminals should remain clear
this morning through late tonight. A weak cold front will bring
lowering ceilings and perhaps some light rain to CEC/ACV early
tomorrow morning, with MVFR ceilings possible. /BRC
.MARINE...Winds have weakened markedly throughout the waters and
have allowed seas to settle somewhat. Area buoys indicate that
significant wave heights have fallen to between 8 to 11 feet with a
dominant period of 13 seconds, although spectral plots indicate that
some steeper locally generated are also mixed into the sea state as
well. While winds have weakened since yesterday, moderate to strong
northerlies will persist across much of the waters south of Cape
Mendocino through the weekend, which will keep seas a bit higher and
steeper in these waters. As such, a small craft advisory has been
put into effect through the weekend for these waters. Elsewhere, a
lingering northwest swell will keep seas elevated at around 8 or 9
feet 12 seconds through tonight.
On Saturday, another large long period northwest swell will move
through the waters, causing seas to build to around 14 to 16 feet.
This may also result in an elevated risk for sneaker waves early
Saturday, particularly along the Redwood Coast where there will be a
lack of steeper wind waves in the waters. Breakers will also build
to around 20 feet or so along northwest facing beaches by the
afternoon. This swell will gradually subside overnight Saturday.
Passing cold fronts Sunday and Monday will usher in strong northerly
winds of around 20 to 25 kt...which will maintain elevated and
somewhat steep seas throughout the waters early next week.
CA...Frost Advisory until 9 AM PST this morning for CAZ101>106-109-
NORTHWEST CALIFORNIA COASTAL WATERS...
Small Craft Advisory until 8 AM PST Sunday for PZZ475.
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