Arcata, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

211
FXUS66 KEKA 161200
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
500 AM PDT Mon Sep 16 2024

.SYNOPSIS...A mix of sun and clouds is expected across the area
today with some afternoon showers in the interior. Another round
of rain showers is expected Tuesday through Wednesday with the
heavier showers in the north. A drying and warming trend is
expected late in the week.

&&

.DISCUSSION...The upper level low is starting to move out of the
area today, but there may still be some showers this afternoon
over eastern Trinity, eastern Mendocino and Lake counties. In the
heavier showers some areas could see local amounts over a quarter
of an inch. Some warming is expected in the inland areas compared
to Sunday, although most inland areas will remain in the 70s.
Monday night a brief period of ridging is expected between the
upper level lows. Temperatures will be chilly, but even the
coldest valleys are only expected to drop into the upper 30s.
Frost is possible in a few of the coldest valleys, but not likely
at this point. At the coast some drizzle is possible as the marine
layer returns.

The next upper level low is expected to move down from the north
just off the west coast Tuesday afternoon and overnight. The
current NBM shows rain developing late Tuesday afternoon and
evening, mainly Humboldt and Del Norte counties. Occasional
showers are expected to continue through Wednesday afternoon.
Current models show the highest rainfall totals around a half
inch in the mountains of Del Norte county. These totals have
trended down in the most recent model runs. This remains a low
confidence forecast due to the uncertainty on the exact track of
the upper level which will dictate where the heaviest precip
falls. Currently there is a big spread between the 75th and 25th
percentile of rainfall totals. The current forecast is generally
on the lower end of this range and may need to be increased as it
gets closer. There is a small threat for thunderstorms in eastern
Mendocino and Lake counties Wednesday afternoon, but again
uncertainty is high due to the differences in the placement of
the low.

Rainfall is generally expected to end Wednesday night. If clouds
clear quickly enough the cool airmass could allow frost to form,
but at this point it doesn`t look likely. Thursday is expected to
see afternoon temperatures rebound quickly with highs in the low
80s in most of the interior valleys. Continued warming is
expected with many areas reaching the low 90s for the weekend. MKK

&&

.AVIATION...Early this morning the coastal terminals are active
with changing cloud ceilings and a threat of some low level wind
shear. While most model guidance showed 2000ft winds around
15-20kts, a few models were suggesting elevated winds near 30kts
at KACV by this afternoon. That said, the threat is not
significant enough to be added to the TAFs, yet should be
considered all along the Redwood coast. Cloud coverage should
remain fairly elevated through the day today before possibly
surging into the coast again around sunset. More confidence on the
stratus situation will arise as more high-res model guidance
becomes available later this morning. Inland at KUKI, winds should
be lighter than yesterday but will still pickup during the day
from the west and calm come nightfall.

&&

.MARINE...Northerly winds with gale force gusts and steep to
hazardous seas with significant wave heights of up to 11 ft are
present in the outer waters early this morning and should remain
through mid-morning. Gradual improvement of the sea state is
expected Monday evening through Tuesday. However, the sea state
will continue to evolve through the work week. A front moving
through the forecast area on Tuesday will force southerly winds,
light rain/mist, and possible areas of dense fog/reduced
visibilities in the coastal waters. Northerlies are forecast to
strengthen again Thursday behind this passing upper level trof,
creating conditions that could be dangerous for small crafts
Thursday afternoon in the outer waters.

&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
None.
NORTHWEST CALIFORNIA COASTAL WATERS...
     Small Craft Advisory until 9 AM PDT Tuesday for PZZ450-455.

     Gale Warning until 9 AM PDT this morning for PZZ470-475.

&&

$$

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For forecast zone information
see the forecast zone map online:
https://www.weather.gov/images/eka/zonemap.png