Area Forecast Discussion
Issued by NWS Eureka, CA

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718
FXUS66 KEKA 292220 CCA
AFDEKA

Area Forecast Discussion
National Weather Service Eureka CA
320 PM PDT SUN MAY 29 2016

.SYNOPSIS...
High pressure will bring dry weather and warming temperatures to
northern California through the upcoming week. The weather pattern
could become more interesting by next weekend.

&&

.DISCUSSION...
.SHORT TERM...
(Tonight and Monday)

More tranquil conditions will return to the area overnight and
tomorrow, as winds continue their downward trend compared to recent
days. The one thing that has been rather stubborn is marine stratus
along the coast in Humboldt County. Similar to yesterday, it finally
mixed out of the Eel River Valley, although here it took its sweet
time today. Looking farther offshore and to our north, clear skies
can be seen on the visible satellite imagery this afternoon,
leading one to believe it shouldn`t be much of an issue tonight.
However, northerly winds will persist so we have some concern this
may redevelop again overnight, but perhaps in more of a scattered
nature. This is something we`ll keep an eye on as the night
progresses.

Otherwise, lighter winds and rising 500mb heights will lead to
warmer temperatures for Monday, as afternoon highs climb about
5 degrees compared to today, with mostly sunny skies expected.

.LONG TERM...
(Monday evening through next Sunday)

Continued warmth and clear skies will be the main theme much of the
week, before things get more muddled for the weekend. An area of
high pressure aloft will traverse the forecast area Monday
night/Tuesday. Clear skies and seasonably warm temperatures will
continue through much of the week.

The ridge axis will pass to our east by Wednesday, with subsidence
becoming less of an issue during the day. The models continue to
show decent instability during the afternoon/evening hours for
locations east of highway 101, with the best overlap of instability
and negligible to no CINH located across the Trinity Alps. Although
no real disturbance is seen in the vorticity pattern to help aid in
convective development, the combination of surface heating,
orographics, and decent instability (SBCAPEs >1500 J/kg) may be
enough for one or two storms to develop. Otherwise, dry conditions
will prevail area-wide.

Heading into the weekend forecast challenges increase, especially
for Sunday. The models continue to "wobble" with regard to the track
of a mid-level area of low pressure tracking towards/across the
state. The GFS has trended farther north, similar to the more
consistent ECMWF regarding the positioning of this feature. However,
it too has shifted the track some towards its GFS counterpart,
shifting its forecast slightly south towards the GFS position. The
Canadian model is in the middle of these two and seems like a good
compromise at this point. In any event, these changes will
continue over the next few days until the system gets closer,
where the leading edge of it can get sampled by our RAOB network.

The end game in all this is things continue to look
interesting/promising for potential convection for the end of next
weekend. Both models continue to show moderate to strong
instability, extremely steep mid-level lapse rates, and
disturbances rotating around the low bringing periods of increased
lift aloft with them. Thunder was added to the forecast for Sunday
to account for this. /PD

&&

.AVIATION...A weak passing shortwave disrupted the offshore flow
this morning. This allowed an area of low clouds to form in around
Humboldt Bay and in the Eel River Delta. These hung around until
early afternoon. These may clear out completely before sunset.
Stronger offshore is expected tonight, however it still doesn`t look
strong enough to keep the clouds and IFR conditions completely out
of ACV, the Humboldt Bay region and the Eel river valley. For now
have them returning at ACV by 0400Z. Expect they may be a bit slower
than this to return, but until it completely disappears will hold
off on changing the forecast. MKK

&&

.MARINE...Strong high pressure over the northeastern Pacific and a
thermal low over the central valley of California is bringing gusty
northerly winds and steep, short period waves to the waters this
afternoon. Tonight the winds are expected to start to diminish. Late
tonight the small craft advisories (SCA) will expire in the inner
waters. This looks on track as the winds turn a bit more offshore
and become light at the coast. Monday afternoon winds will increase
again, but they are expected to remain slightly below small craft
advisory levels. This will need to be watched as it gets closer.

Tuesday winds look to become more southerly in the southern waters
as a southerly surge of stratus moves north. It is possible we could
see gusts to 20 kt with this surge, but will wait until it gets
closer to add it to the forecast.

Northerly winds will return Thursday into the weekend and will be in
the fresh to strong category, but current forecasts show them
remaining below gale force.

Meanwhile, model guidance continues to hint at a long period south
swells moving through the waters Wednesday. This will bring
increased wave activity to south facing beaches and anchorages with
only minor impacts expected. MKK

&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
NORTHWEST CALIFORNIA COASTAL WATERS...
     Small Craft Advisory until 3 AM PDT Monday FOR PZZ450.

     Small Craft Advisory until 3 AM PDT Tuesday FOR PZZ470.

     Small Craft Advisory until 3 AM PDT Monday FOR PZZ455.

     Small Craft Advisory until 3 PM PDT Monday FOR PZZ475.

&&

$$

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