Lewiston, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

359
FXUS66 KEKA 131103
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
403 AM PDT Sun Apr 13 2025

.SYNOPSIS...
Dry conditions are expected today and Monday as an upper ridge
builds over the West Coast. Highs into the mid 80s will occur in
many interior valley locations on Monday. Cooler temperatures and
the chance of mountain thunderstorms will develop Tuesday into
Wednesday as an upper low drifts north from Southern California.

&&

.DISCUSSION...
An upper level ridge is now building over the West Coast and this
ridge will bring warming temperatures to the region, especially over
the interior. High temperatures today will approach, or in some
places exceed, 80 degrees today in the interior valleys. Coastal
areas will remain seasonably cool due to the marine layer and a weak
offshore pressure gradient. Additional warming will occur on Monday
with most interior valleys pushing into the mid 80s.

The 80s won`t last long though as an upper low cuts off from the
flow along the coast of Southern California and then drifts back
north on Tuesday into Wednesday. This will bring cooler
temperatures back to the region at the surface and aloft,
increasing instability during the afternoon and evening hours. The
GFS is the most ambitious for moisture return during this period
but the ECMWF has been trending wetter with recent runs. This, in
combination with the ensemble output lining up with similar
solutions, is enough to introduce thunderstorm chances over
primarily Trinity, eastern Mendocino, and Lake counties Tuesday
and Wednesday.

The next question will be how a second, much stronger upper trough
progresses into the western US as it dives south from western Canada
Thursday into Friday. Additional chances for showers or storms over
the interior mountains could be possible Thursday and Friday
depending on how far west this trough digs into California. /RPA

&&

.AVIATION...
Clear skies and generally calm to light surface east to northeast
winds this morning. Strongest easterly winds have developed
overnight, but these remain above 2000 feet MSL limiting the
potential of wind shear. Expect prevailing VFR conditions at all
terminals at least during the next 24 hrs with high pressure over
the area promoting a strong subsidence. A weaker easterly offshore
flow component will continue to keep the coast free of stratus
and fog tonight. Short-term guidances are suggesting a shallow
marine layer redevelopment late tonight and Monday.

&&

.MARINE...
Gale force gusts persist across the outer waters through this
morning. Conditions gradually improves throughout the day today as
a high pressure builds in and the pressure gradient relaxes.
Northerly winds will continue to ease across the waters today and
into Monday, but will remain elevated across the outer waters
through tonight. Winds will become gentle to moderate breezes out
of the north on Monday. Seas in the outer waters will likely
remain within advisory criteria through Monday morning even as
winds diminish.

Northerly winds increase again Monday evening into Tuesday, with
strong breezes to gale force gusts possible in the outer waters,
especially north of Cape Mendocino. Seas will respond with 13-15 ft
significant wave heights possible in the outer waters. Lighter winds
are forecast nearshore, but conditions could still be hazardous to
small crafts as steep seas of 7-10 ft are possible along with wind
gusts of 20-25 kts by Wednesday. ZVS/JB

&&

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

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

&&

$$

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