461 
FXUS66 KEKA 061036
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
336 AM PDT Wed Oct 6 2021

.SYNOPSIS...Cool and mainly dry weather will occur across the
region through Friday. A warming trend will then take place this
weekend, followed by the passage of a strong cold front Sunday
night into Monday.

&&

.DISCUSSION...A light frontal rainband was moving east across 
Trinity County early this morning. As that feature exits the 
region, large-scale subsidence and a drier airmass will spread 
across NWRN CA. Clear skies will be probable this afternoon as a 
result across much of the EKA CWA, though a cool post frontal 
airmass will yield below normal temperatures. Otherwise, an upper-
level trough centered immediately offshore is forecast to 
fracture into two pieces during Thursday. The southern piece is 
expected to eject eastward across CNTRL/SRN CA during Friday. 
Associated precipitation development will subsequently remain 
south of NWRN CA. In addition, pockets of clear skies Friday 
morning, and again Saturday morning, will aid in frost/freeze 
conditions across interior wind sheltered valleys.

Model guidance supports building midlevel heights during the
weekend, which signals a likely warming trend across the region,
with interior valley highs rebounding back into the 70s to low
80s. Thereafter, multi-model guidance supports the rapid
amplification of a significant upper-level trough over the WRN
CONUS Sunday night into Monday. A strong cold front is forecast 
to sweep southward during Sunday evening as the trough digs across
the Pacific Coast. A tight northerly post-frontal pressure 
gradient combined with 30 kt north-northwesterlies in the 925-700 
mb layer will favor breezy north winds across the region, 
particularly during Monday afternoon as the boundary layer 
destabilizes and maximizes mixing of stronger momentum aloft down 
to the surface. Winds are then forecast to weaken Monday night 
into Tuesday morning, and when combined with a dry airmass and 
clearing skies, may aid in localized hard freeze conditions for 
communities such as Hayfork.

Garner

&&

.AVIATION...Mid to high clouds persist over most of the area as a
frontal boundary continues to exit the region. Some light mist 
will be possible at both coastal terminals this morning, likely 
keeping conditions around MVFR. MVFR to VFR conditions will be 
possible along the coast later this morning and this afternoon. 
Breezy afternoon winds are forecast at both KCEC and KACV this 
afternoon as northerlies start to ramp up offshore. VFR conditions
are expected to prevail at KUKI. Otherwise, there may be some 
low-level wind shear around KACV around 24 to 28 knots or so this 
morning.

&&

.MARINE...Moderate to fresh northerlies will expand northward 
into the northern outer waters and increase to fresh breezes over 
both outer zones later today. Steeper, short-period seas will 
build in response to these increasing northerlies. Winds nearshore
will hover mostly between gentle to moderate breezes, except 
around Point Saint George and Cape Mendocino where mostly fresh 
breezes can be expected. These elevated winds and seas will 
persist through early Friday morning and will gradually weaken 
throughout the day on Friday. Otherwise, a northwest swell will 
build through this evening and then slowly wane through Thursday, 
and a small northwest swell is forecast to take its place.

&&

.FIRE WEATHER...Cool and humid post-frontal conditions will 
prevail across the region through Friday, followed by a warming 
and drying trend this weekend. Early next week, a strong upper-
level storm system is forecast to move east across the western 
United States, while an associated cold front moves south across 
northern California. Strong north winds may develop in the wake of
the front during Monday and aid in elevated fire weather 
conditions across Lake and interior Mendocino Counties.

Garner

&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
None.
NORTHWEST CALIFORNIA COASTAL WATERS...
     Small Craft Advisory from 11 PM this evening to 3 AM PDT 
     Friday for PZZ450.

     Small Craft Advisory from 5 PM this afternoon to 3 AM PDT 
     Friday for PZZ470.

     Small Craft Advisory until 3 AM PDT Friday for PZZ455.

     Small Craft Advisory until 3 AM PDT Friday for PZZ475.

&&

$$

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