042
FXUS66 KEKA 041300
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
412 AM PDT Sat May 4 2024

.SYNOPSIS...A passing cold front will continue to bring periods of
heavy rain early this morning, with snow above 2500 feet. A much
colder airmass will then settle in behind the front to bring near
freezing to freezing temperatures for some interior valleys.


&&

.DISCUSSION...A late season cold front brought widespread heavy
rainfall rates up to 0.5 inches per hour overnight, with activity
continuing this morning as it moves southward. Soils, creeks,
rivers, and gutter systems have handled the water well with non-
advisory level issues observed so far. Interior snowfall continues
as snow levels are quickly dropping. The Winter Weather Advisory
remains for elevations above 2500 feet. A seasonably anomalous, cold
upper low will work its way over N CA throughout the day. Associated
instability and 700mb temperatures as cold as -13C will bring
showers and possibly a thunderstorm, some which could contain small
hail through this evening. Colder to much colder than average
tempertures will remain in place through the weekend and into next
week. Near freezing to freezing temperatures for some interior
valleys are forecast, but expected fog and lingering cloud cover
will hold the temperature up for some valleys over the next couple
of nights. Zonal flow followed by a weak shortwave on Monday will
bring more unsettled weather and drizzle to light rain. A pronounced
ridge of high pressure will then begin building in mid to late next
week, and there is growing probability for the warmest interior
valleys to exceed 85 degrees through that period.
/JJW


&&

.AVIATION...Biggest problem to deal with to start the forecast will
be ceilings in the IFR to MVFR range behind a cold front as wind has
shifted to the west. Cold front aloft will play a part in some
thunderstorm potential this afternoon and evening, although chances
are quite small. Ensembles indicate the chance of MVFR or worse
ceilings dips below 50% along the coast by about 21-22Z, and toward
17Z for KUKI. For visibility, the overall trend is for improvement
in visibility for all TAF sites, except for some potential that some
slight worsening of visibility will occur within the first couple of
hours of the forecast. Can`t rule out the potential for small hail
accumulation for the coast this afternoon and early evening. We may
not completely lose our light rain or drizzle potential through the
night tonight and into early Sunday morning.


&&

.MARINE...After strong winds occurred directly behind a passing
cold front earlier this morning, gusty northwest winds will become
confined to the southern waters by late this morning, with the
potential for thunderstorm development. Steep wind wave response
expected late today through Sunday as lingering showers dissipate.
Combined seas today are forecast to be 5-7 feet with 7-9 second
periods through the weekend before a long period northwest swell
fills in early next week. Strong northerlies combined with another
steep northwest swell by Tuesday night or Wednesday may produce
combined seas exceeding 10 feet.

A few persistent northwest swells for the next several days will
play a factor in combined wave height increasing by mid-week. Small
craft advisories are all ending by mid-evening tonight.


&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
     Winter Weather Advisory until 11 AM PDT this morning for
     CAZ102-105>108-111.

NORTHWEST CALIFORNIA COASTAL WATERS...
     Small Craft Advisory until 9 AM PDT this morning for PZZ470.

     Small Craft Advisory until 9 PM PDT this evening for PZZ475.

&&

$$

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