Area Forecast Discussion
Issued by NWS Eureka, CA

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000
FXUS66 KEKA 241048
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
348 AM PDT Fri Mar 24 2017

.SYNOPSIS...
Widespread rainfall will continue today, ahead of an approaching
cold front, with gusty winds possible along and west of the coastal
ridges through this morning. Precipitation will become more showery
by tonight. A brief break is the rainy pattern is expected Saturday
evening and overnight, before another storm system brings additional
widespread rainfall, with gusty winds likely along the coast, in the
Sunday through Monday time frame. Tuesday morning looks to be dry,
before more wet weather returns by the evening.

&&

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

The storm system passing through our region hasn`t disappointed in
its fan fare, as widespread gusty winds developed yesterday evening
and overnight as expected. So far, portions of the Redwood Coast
have seen gusts from 40 to 45 mph near Fortuna and Humboldt Bay, to
near 55 mph at the Coast Guard station near Crescent city. Area
ridges have been right on track too, with gusts in the 50 to 65 mph
range observed. The widespread rainfall is also well underway, with
even a convective line trying to develop within the larger
stratiform rain shield across the northern outer waters. Doppler
radar velocity data indicates some kinks in the link, where weak
transient mesocyclones development is trying to develop. This is
largely being dynamically forced though, as the latest SPC
mesoanalysis shows MUCAPEs running less than 100 J/kg. That dearth of
instability is what`s keeping this with manageable (no warning
needed) levels right now. However, we`ve seen spin-ups before with
little or no instability, so we`ll keep an eye on things as it
approaches the coast, as if line integrity is maintained, some
"enhanced" wind gusts would be possible.

Otherwise, once the cold front moves ashore, precipitation will
become more showery in its wake. Mid-level cooling isn`t that
impressive, as lapse rates struggle to top 7 deg. C/km. Still, 700mb
lifted indices do climb into the -1 to -2 range with perhaps ~100
to 200 J/kg of MUCAPE forecast. Thus, while it`s certainly the best
convective setup, thunder mention was retained and slightly expanded
given the kinetics involved with the system still sufficient behind
the front to aid the updraft strength/heights, possibly getting a
boost from diurnal heating should sufficient breaks in the cloud
cover develop. Heading into the overnight hours, precipitation
should continue on its downward trend in terms of coverage.

.LONG TERM...
(Saturday through Thursday)

Trying to get your yard work done this week will be like riding a
roller coaster, if you`re looking for dry weather to get it done.
As todays storm system continues to depart the area, brief ridging
will build across the region for Saturday afternoon/evening,
persisting into Sunday morning. However, just like a scene in a movie
you may know, Sunday into Monday will be like waking up to the same
theme as you head into Sunday evening/Monday morning. Another storm
system passing by to our north will send its trailing cold front
through the region during this time. Similar to the past 18 hours,
gusty coastal winds will develop ahead of it, with widespread
rainfall developing along and behind it. Another transient (brief)
ridge of high pressure looks to take up temporary residence for
Monday evening into Tuesday morning, before another system brings
more light rainfall.

As for snow levels and temperatures, some higher elevation snowfall
is likely through Monday, with snow levels generally in the ~4000 to
5000 feet range. Much warmer air aloft will advect into the
northwestern California by the middle of the week, with snow levels
climbing well above 6000 feet. Temperature wise, afternoon highs
will mainly be near seasonal values, with lows close to average for
most of the forecast period. The one exception to this will be when
we`re between systems, where decreased cloud cover and light winds
could allow morning temperatures to drop a few more degrees. /PD

&&

.AVIATION...
VFR to MVFR conditions will continue at KCEC and KACV today as a
cold front moves across the region. The lower conditions will be
due to reduced ceilings and/or visibilities. Showers will continue
moving across the region at times today. Moderate and gusty winds
will continue at KCEC and KACV through the early morning. The
winds will diminish late this morning and this afternoon in the
wake of the cold front. VFR TO MVFR conditions will occur at KUKI
with the cold front moving across the region and showers moving
across the area at times today. The lower conditions will be due
to reduced ceilings and/or visibilities. Light winds will continue
at KUKI today with calm winds occurring overnight tonight.

&&

.MARINE...
Gusty winds and elevated seas will continue across the waters through
the early morning as a cold front moves across the region.
Showers will move across the waters at times today associated with
the cold front. The winds and seas will gradually diminish later
this morning and this afternoon in the wake of the cold front.
Light winds will prevail across the waters Saturday. However the
winds and seas will increase Sunday as a weak cold front moves
across the waters. Showers will move across the waters at times
Sunday and Monday associated with this next cold front. The seas
will increase Sunday and remain elevated through the end of this
forecast period on Tuesday. Gale warnings will continue across the
northern waters and southern outer waters through the early
morning. A small craft advisory will remain in effect across the
southern near shore waters through this afternoon.

&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...Wind Advisory until 5 AM PDT early this morning for CAZ101>106.

NORTHWEST CALIFORNIA COASTAL WATERS...Gale Warning until 9 AM PDT this morning for PZZ450-470-475.

     Small Craft Advisory until 3 PM PDT this afternoon for PZZ455.

&&

$$

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