921
FXUS66 KEKA 011300
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
600 AM PDT Sat Jun 1 2024

.SYNOPSIS...Conditions in the northern areas are expected to
deteriorate this weekend before a short spurt of wetting rainfalls
arrives Sunday night into Monday. Southern areas will cool off
but are not expected to experience any meaningful precipitation at
this time. Next week, temperatures will soar to well above
average from the interior to the coast, possibly reaching over
100F in some places.



&&

.DISCUSSION...A brief weak shortwave moved by overnight. Despite
a narrow area of mid to high level cloudiness, moisture was
limited. Stratus and patchy fog blanketed much of the Humboldt
coastal waters, and expanded well up the adjacent river valleys.
The McKinleyville profiler indicates a marine layer depth up to
around 2,500 feel MSL. Patchy drizzle may occur with a slightly
deepening marine layer in the vicinity of Humboldt Bay this
morning. Otherwise, stratus are expected to gradually lift and mix
out by late morning. However, expect a partly to mostly cloudy
skies as mid to high level clouds spread across the area.

Temperatures today will run 5 to around 10 degrees cooler
compared with yesterday`s readings across the interior, while
seasonal temperatures remains along the coast. Inland highs are
forecast to be in the mid 70s to mid 80`s. A last push of gusty
northwest winds in Mendocino and Lake counties will occur today as
the tightest pressure gradient shifts south over those counties
bringing gusts to around 30 mph or locally higher on some ridge
tops during the afternoon and evening.

Sunday into Monday, models consistently show the track of a late-
season low pressure system approaching the Pacific NW. South of
that feature, a broad zone of WAA and west-southwesterly moisture
flux will aid in light rain or sprinkles over coastal Del Norte
Sunday morning. PWAT values are expected to increase to around 1
to 1.5 inches along the California Coast by Sunday afternoon as
the frontal system sag into NW California. The 00z ECMWF Extreme
Forecast Index (EFI) continues to suggest a high-end event
climatologically, with EFI values in excess of 0.7 for most Del
Norte County and northern Humboldt. Heaviest rain is forecast to
occur late Sunday night into Monday morning in Del Norte and far
northern Humboldt, as a west- southwesterly IVT plume intersects
the coastal terrain. Rain rates looks to remain below 0.3 in/hr
across Del Norte County. NBM probabilities range from 45% to
around 60% of an inch or more late Sunday night into Monday
morning those two counties. Overall this should only be a
beneficial rain.

Rain chances will quickly decrease farther south and east into
Trinity and Mendocino counties where by the farther south portions
of Mendocino and Lake counties may see no rain at all. The front
will move through the entire region by Monday evening.

Quickly behind this front ridging will build back over the west
coast allowing temperatures to rebound quickly into the 90s and even
to near or exceeding 100 degrees in Lake County on Wednesday and/or
Thursday. With the expanding heat there will also be increasing heat
risk in the far southeastern portion of the area, particularly near
Clearlake. In coordination with the weather office in Sacramento, we
went ahead and issued an excessive heat watch from Tuesday
through Thursday to highlight this risk. At this time it`s more
likely that only heat advisories will be needed but it isn`t
impossible that warning thresholds could be reached when the heat
peaks mid week.


&&

.AVIATION...Stratus development has been isolated to the Humboldt
coast, south of Orick and down to Capetown. This equates to VFR and
light southerly winds at KCEC switching to a westerly prevailing
wind before the afternoon. That said, stratus has developed over
KACV with ceilings above 1000ft and visibility not being impacted as
much. Expect MVFR to last through the morning at KACV with a few
periods of IFR if ceilings dip below 1000ft, which is possible by
dawn. Light southwesterly winds at KUKI this morning will see a
return to gusty northerly winds by the early afternoon with VFR
conditions continuing throughout. Low Level Wind Shear, LLWS, at
KUKI is probable as winds mix down before the afternoon. /EYS


&&

.MARINE...Gale force gusts have become less frequent in the southern
outer waters yet, hazardous seas conditions remain as steep waves
continue around 9 - 10 ft and as many seconds in period. Gusts in
the low 30`s are still being reported at Point Arena as of 11z
(4AM), this morning. Gusty winds and steep waves will subside by the
late afternoon and remain isolated to a narrow area south of Cape
Mendocino. This weekend, an upper level trough is expected to weaken
the winds. Sunday a northwest swell around 10 seconds will be the
main wave. Initially it is expected to be around 3 feet, but will
build to around 6 feet at 10 seconds by Tuesday. Larger combined
wave heights are expected Wednesday, 13 to 15 feet. /EYS


&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
     Excessive Heat Watch from Tuesday morning through Thursday
     evening for CAZ114-115.

NORTHWEST CALIFORNIA COASTAL WATERS...
     Small Craft Advisory until 9 AM PDT this morning for PZZ450.

     Small Craft Advisory until 3 AM PDT Sunday for PZZ455.

     Small Craft Advisory until 1 PM PDT this afternoon for
     PZZ470.

     Hazardous Seas Warning until 9 AM PDT this morning for
     PZZ475.

&&

$$

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