Area Forecast Discussion
Issued by NWS Eureka, CA

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FXUS66 KEKA 251256 CCA

AREA FORECAST DISCUSSION...corrected aviation and marine
National Weather Service Eureka CA
555 AM PDT Sat Mar 25 2017

A few hit and miss remain possible today, mainly this morning into
perhaps early afternoon, primarily for locations north of Mendocino
County. Brief ridging will bring a temporary dry spell area-wide
tonight into Sunday morning, before another storm system brings
widespread rainfall, higher elevation snowfall, and gusty winds to
locations along and west of the coastal range. The on again off
again showery pattern will persist through Thursday morning, before
dry weather returns for the remainder of the week.


(Today and Tonight)

Showers remain possible through the first half of the day, before a
brief dry period commences tonight. As one storm system to our
southeast departs the region, the trough axis is in the midst of
crossing the forecast area early this morning. Additional jet energy
diving into the backside of this trough is what has let to a slight
increase in the showers this morning. This will hold true through
the first half of the day, before brief/weak ridging at the surface
and aloft overspreads the region while persisting into Sunday
morning. look for afternoon highs to top out near seasonal values.

However, the next system will be quickly on the heels of the
departing trough, with clouds riding the ridge and spilling over the
area, resulting in only a slight decrease in cloud cover at best by
morning. The positive effect of the clouds will be better nocturnal
insolation, helping overnight lows remain a few degrees warmer,
perhaps giving your furnace a little bit more of a break.

(Sunday through Friday)

An off and on wet pattern will persist through the first half of the
week, before a pattern change brings increased sunshine and drying
to all of northwestern California. Before we get to that though, the
aforementioned storm system for Sunday will be moving into our neck
of the woods. A fairly strong area of low pressure will be
undergoing an occlusion process as it treks across the southeastern
Pacific/southern Gulf of Alaska region, sending a trailing cold
front eastward. Ahead of this front, a 925mb jet of 45 to 50 knots
will develop across the outer waters and along the Redwood Coast
from Cape Mendocino north, in the late Sunday morning into the
afternoon time frame. This could bring some gusty winds to locations
to portions of Humboldt and Del Norte counties. However, winds look
to be slightly less than yesterdays system.

As the front crosses the region during the afternoon and evening
hours, widespread rainfall will spread from west to east. Overall,
rainfall amounts don`t look to be too significant, but some locally
heavy rainfall is expected, mainly for portions of Humboldt and Del
Norte County along the south and west facing slopes. Things will be
on a downward trend for Monday, as precipitation becomes more
showery. Some higher elevation snowfall will occur during this time
as well, with snow levels gradually dropping from ~4500 to 3500
feet. Amounts will be light enough though to preclude any real
impacts to area passes, with the exception being Scott Mountain
Pass, where some light accumulations will occur. As for the
convective potential, although 700mb and 500mb lifted indices do go
slightly negative, modest mid-level lapse rates and negligible
MUCAPEs preclude any thunder inclusion in the zones (forecast) at
this time.

Another brief period of transient riding will build across the
region Monday evening into early Tuesday morning, with more dry
weather expected. However, another weak disturbance in the flow
aloft may bring additional precipitation back into the area for
Tuesday afternoon into Thursday morning time frame. this will need
to be watched though, as the models have shown a slight northward
drift in precipitation with some delay also seen in timing. In any
event, after this latter system, high pressure looks to build across
the state with perhaps a prolonged period, featuring mainly clear
skies and dry conditions. /PD


VFR conditions and light winds to calm conditions will continue at
KCEC, KACV and KUKI today as a weak high pressure ridge extends
across the region. However a few Showers may move across some areas
at times today. Any showers may temporarily reduce ceilings and/or
visibilities to MVFR conditions at times primarily during the


Light winds and moderate seas will continue across the waters through
tonight as a weak high pressure ridge extends across the region. The
winds and seas will increase Sunday as a weak cold front approaches
the waters. The front will move across the waters Sunday evening.
Showers will move across the waters at times Sunday associated with
the cold front. The winds will increase Sunday. The winds and seas
will be higher across the outer waters and in or near any showers.
The winds will diminish Sunday night. Seas will increase Monday and
remain elevated through Wednesday as a westerly swell propagates
across the waters. Small craft advisories are likely across all the
waters Sunday due to increasing winds as the cold front moves across
the waters.  Small craft advisories are likely across all the waters
Monday through Wednesday due to elevated seas associated with the
westerly swell.




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