428
FXUS66 KEKA 231101
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
401 AM PDT Sun Jun 23 2024

.SYNOPSIS...Interior warm and dry conditions continue through Tuesday
while marine stratus dampens coastal temperatures. An upper level
disturbance mid-week will allow for relatively cooler temperatures
through Thursday. Warming trend returns for this weekend into next
week.


&&

.DISCUSSION...Light northerly onshore flow behind a weak frontal
boundary lends favor to marine stratus development on the north
coast this morning, especially north of the Cape and into the Eel
River Valley. Crescent City, Eureka and Fortuna have reported
visibility`s <1 mile for the last several hours. This additional
surge of moisture beneath a moderate marine inversion will likely
delay clearing until early afternoon - HREF indicates 15-25%
probabilities for light drizzle and minor precip accumulations along
the Humboldt coast before NW winds increase and stratus scatters
out. Gusts to 40 mph are likely along coastal headlands this
afternoon as the thermal trough strengthens. Highest probabilities
center around Cape Mendocino and Point St. George.


Hot, summer-like temperatures are forecast for the interior today
beneath a broad upper ridge over western CONUS. Widespread
temperatures in the upper 80`s and low to mid 90`s expected, with
NBM probabilities favoring highs exceeding 95 and
approaching/reaching 100 degrees again in the valleys of Southern
Mendocino, Lake and eastern Trinity counties. This pattern is
expected to remain largely consistent, perhaps tamped down a few
degrees for the start to next week, through Tuesday with daily
surges in diurnally driven NW flow. Coastal highs will remain
significantly dampened by daily marine stratus redevelopment.

An upper level pattern change is expected Wednesday into Thursday as
mostly zonal flow is interrupted by an upper level trough dropping
into the PNW, inducing relative cooling of temperatures and slightly
elevated westerly winds. NBM high temperature probabilities drop
off significantly in the low 90`s for the interior valleys,
especially on Thursday following a weak frontal passage. Long
range models are hinting at potential precip in Humboldt and Del
Norte counties in the wake of this front, although probabilities
for measurable precip are quite low. Otherwise, 500 mb clusters
are beginning to align in favor of relatively zonal flow turning
over to broad ridging late next weekend, allowing for another
warming trend.



&&

.AVIATION...LIFR stratus and fog blankets the coast once again this
morning. Fog is expected to lift and peel back to the immediate
coast by early this afternoon, with VFR expected this afternoon for
portions of the coast. Inconsistent IFR ceilings and visibilities
will most likely start to return early this evening, likely dropping
to LIFR late tonight. Otherwise, widespread VFR conditions will
persist for the interior with normal summer conditions.

&&

.MARINE...Northerly winds strengthen again today. This will bring
gusts to 20 kts and above along with steep short period seas
throughout all waters, with Gale Force gusts expected in the usual
spots downwind of Cape Mendo and near Pt St George. Northerly winds
will weaken during Monday, and by Monday evening only the southern
waters are forecasted to support short period seas steep enough for
a small craft advisory. Meanwhile a minor northwest swell of 5 feet
at 11 seconds will fill in early Monday morning. Northerlies are
then forecast to remain below 15 kt for most zones during midweek,
aside from the persistent 15-20 kt northerlies expected directly
downwind of Cape Mendo. Winds may strengthen again Friday into next
weekend.


&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
None.
NORTHWEST CALIFORNIA COASTAL WATERS...
     Small Craft Advisory from 3 PM this afternoon to 3 PM PDT
     Monday for PZZ450.

     Small Craft Advisory until 3 PM PDT Monday for PZZ455.

     Small Craft Advisory until 3 PM PDT Monday for PZZ470.

     Small Craft Advisory until 3 AM PDT Tuesday for PZZ475.

&&

$$

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