587
FXUS66 KEKA 232149
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
249 PM PDT Mon Sep 23 2024

.SYNOPSIS...One more day of hot weather is forecast in the interior
on Tuesday. Cooling is expected on Wednesday, followed a warming
trend Thursday and Friday. Coastal stratus with patchy fog will
likely return around mid week.

&&

.DISCUSSION...Deep column of warm air aloft coupled with offshore
wind flow has been resulting in warmer temperature along the
coast and in the interior of NW California today. Temperatures
have been running 5 to 15F warmer compared to yesterday at this
time. Temperatures are projected to peak around 95-104F in the
interior valleys. Anomalous warmth has also been occurring over
coastal areas and adjacent river valleys. Crescent City airport
has reach 72F while Fortuna airport warmed up to 77F.

Hot weather with highs 5 to 15F above normal is forecast to
continue in the interior on Tuesday. Weakening offshore flow and
afternoon sea breezes will probably result cooling for much of
the coast on Tue, although temperatures may rapidly warm up into
the lower to mid 70s in the morning before a shallow layer of
cool-damp marine air returns. Heat risk in the interior is forecast
to remain moderate through Tuesday except within the thermal belt
where overnight lows in the 70`s are expected. This level of heat
affects most individuals sensitive to heat, especially those
without effective cooling and/or adequate hydration.

High pressure aloft will begin shift eastward Tuesday night as an
upper level trough approaches the Pacific Northwest. Meanwhile, a
dry cutoff low located offshore southern California will drift
northward parallel to the coast before being absorbed by the
upstream trough by early Wednesday. Marine layer will likely
develop during this time frame. Daytime high temperatures will
diminish to near or below seasonal averages in the interior.
Seasonal averages range from 82-88F in the interior. Chances for
precipitation with this incoming trough is quite meager, generally
10% or less. If anything, some light drizzle may occur in coastal
areas with no impacts.

Ensemble means and deterministic guidance indicates above normal
500mb heights and above normal 850mb temperatures Thu-Sun. This
will most likely result in above normal interior high temperatures.
How much above normal is not 100% certain. Looking at the
National Blend of models (NBM), sure enough chance for 90-95F
increases as early as Friday. Dry weather and above normal
interior high temps are most probable Fri-Mon. DB

&&

.AVIATION...Benign "flying" weather conditions generally prevailed
across the region today. However, there were a few brief early
morning pockets of LIFR/IFR stratus and fog...mainly near CEC.
Cirrus clouds streamed across the region, otherwise skies were
SKC. The pressure gradient along the Del Norte Coast promoted
breezy to some gusty diurnal winds. Also, marginal above ground
winds over Del Norte were the catalyst for LLWS until noonday.
Overnight/Thursday morning: a consensus of a couple of model data
indicates that the marine layer will redevelop at the coast and
cause low Cig/Vis at ACV and CEC terminals. However, model data is
also indicating pronounced offshore flow overnight which would
promote a lack of clouds (for the most part); Bufkit agrees with
that scenario. On the 18z Tafs though, some low cloud and
visibility obstructions. /TA



&&

.MARINE...Northerly winds and steep waves will continue to
diminish tonight through Tuesday. A series of mid period NW swell
groups will build through mid week and peak around 8 ft on Wed.
Potential for gale force northerlies and large steep waves over 10
feet will increase Fri-Sat. DB

&&

.FIRE WEATHER...Elevated conditions with low daytime RH`s and
locally gusty winds are forecast to continue through Tuesday.
Temperatures will remain hot on Tuesday with daytime RH`s from
10-20%. Offshore flow will continue on Tue, however ridge level
winds will become southeasterly by early Tue morning, and then
turn westerly to southwesterly in the afternoon. A trough will
move across the area on Wed and daytime temperatures will cool
down. RH`s should also increase on Wed-Thu, but minimum RH`s will
still be low, around 20-30% in the interior. Warmer and drier
conditions with stronger N-NE winds expected Fri-Sat. Elevated to
locally critical conditions will be possible. DB

&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
None.
NORTHWEST CALIFORNIA COASTAL WATERS...
     Small Craft Advisory until 8 AM PDT Tuesday for PZZ470.

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

&&

$$

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