Area Forecast Discussion
Issued by NWS Eureka, CA

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157
FXUS66 KEKA 231129
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
429 AM PDT Mon Sep 23 2019

.SYNOPSIS...Warm and dry conditions will occur across the region
through Wednesday. Thereafter, cooler and potentially showery
weather will spread across the area this Friday through the
weekend.

&&

.DISCUSSION...Large-scale subsidence is occurring across the
region as an upper trough departs east across the Great Basin, and
a ridge builds eastward from the NERN PAC. A moist antecedent
airmass at the surface due to recent rainfall was aiding in patchy
fog along the coast Monday morning, but clear skies will occur
across all of NWRN CA by this afternoon as a warm dry airmass
spreads southeast with the development of offshore winds.
Abundant sunshine and warm offshore winds will aid in high
temperatures in the 80s to near 90 across the interior
today...with further warming into 90s to near 100 on Tuesday and
Wednesday.

Much cooler weather is forecast to spread south across NRN CA
Friday into the weekend as a large upper trough digs over the WRN
CONUS. Interior highs are forecast to cool into the 60s by
Saturday, and overnight lows near freezing will be possible across
wind sheltered valleys in Trinity County Sunday night and Monday
night. In addition to the cooler weather...light showers are
expected to develop across the region Saturday and Sunday.
However, impacts associated with shower activity will likely be
minimal.

JMG

&&

.AVIATION...Sky conditions have improved overnight as high
pressure rapidly builds behind yesterdays weak weather system.
Widespread VFR conditions are expected to continue throughout the
day and even over the next few days as some drier offshore flow
moves through the area. Afternoon NW winds develop along the coast
and become quite gusty on Tuesday and Wednesday.

&&

.MARINE...A fresh round of headlines is poised to go into effect
across the coastal waters as winds and seas quickly ramp up today
behind the departing trough. Small Craft Advisory conditions will
develop across the outer waters and continue to increase to gales
later today. Gale warnings are in effect for the outer waters
while hard sca`s are in effect for the inner waters. The Gales
look to persist across the outer waters through Thursday, which
will allow short period seas to build into the 15 to 18 foot range
by the middle of the week. Although the strongest winds are
generally expected to remain farther offshore, the steeper seas
being generated beyond 10NM will spread into the nearshore zones
and produce potentially hazardous seas in the 12-15 foot range
during the middle of the week. A Haz Seas watch is in effect to
reflect the potential for the rough sea state.

&&

.FIRE WEATHER...Surface high pressure is forecast to build south
from Oregon into Nevada through Wednesday. North-northeast
ridgetop winds will strengthen in response to the high, with gusts
from 20 to 30 mph possible Monday night and Tuesday night. The
gusty winds combined with afternoon RH values in the teens
followed by poor overnight recovery will aid in locally critical
fire weather conditions over portions of Mendocino, Lake, and
extreme southern Trinity Counties.

JMG

&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...Red Flag Warning from 9 PM this evening to 11 AM PDT Wednesday
     for CAZ276-277.

NORTHWEST CALIFORNIA COASTAL WATERS...Small Craft Advisory until
     3 PM PDT this afternoon for PZZ470.

     Gale Warning from 3 PM this afternoon to 2 PM PDT Thursday for
     PZZ470.

     Small Craft Advisory from 9 AM this morning to 5 PM PDT Thursday
     for PZZ450-455.

     Hazardous Seas Watch from Tuesday afternoon through Thursday
     afternoon for PZZ450-455.

     Small Craft Advisory until 9 AM PDT this morning for PZZ475.

     Gale Warning from 9 AM this morning to 5 PM PDT Thursday for
     PZZ475.

&&

$$

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