762
FXUS66 KEKA 190711
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
1211 AM PDT Tue Aug 19 2025

.SYNOPSIS...A gradual warming and drying trend will continue and
intensifies late this week with inland temperatures warming to above
100 into the weekend. This will create fire weather concerns and a
Moderate to Major HeatRisk.


&&

.DISCUSSION...Stratus should be less of a hindrance on the coast
overnight as satellite imagery shows less low cloud development
or advection into deltas and valleys. Tuesday will be fairly mild
as the anticipated late week ridging and high pressure regime sets
in. Wednesday does show a shortwave perturbation clipping the
northern region, but is expected to have little impacts other
than suppressing the greater inevitable warmup. Beyond the passing
of the shortwave, temperatures will indeed warm late in the week
with a strengthening Four Corners Region High. 500 mb heights are
forecast to reach 594 to possibly up to 597 dm Friday. This setup
has strong reliability and high forecast confidence for hot
temperatures through our region. The probability for isolated
warmer valleys to exceed 100 increases Thursday. Chances for
temperatures over 100 are highest Friday (90%) for the interior
valleys. The hot daytime temperatures and warm overnight lows will
bring Moderate to some areas of Major HeatRisk late this week and
into the weekend. Chances for high tempertures over 100 begin
slowly dropping for some Saturday, but they will be similar to
Friday for most. Troughing will deepen from the north by Sunday.
This will begin weakening the Four Corners high and start slowly
trending temperatures back down.

The Four Corners region high will tap into monsoonal moisture at the
end of the week. Models clip our area with some of this moisture
late Friday and through the weekend. Currently, the moisture quality
and instability look too low to raise thunderstorm chances, but this
will have to be watched closely for fire weather concerns with the
dry surface conditions and likeliness of little to no precipitation
from anything that forms. /JJW /EYS


&&

.AVIATION...(06Z TAFs)...Very early Tuesday morning, Northwest
California remains VFR. However, at some point before sunrise,
coastal stratus is expected to develop and potentially affect
coastal terminals with periods of IFR to LIFR conditions. Due to a
weaker inversion, if coastal stratus does develop, it`ll clear
rather quickly after sunrise. Otherwise, interior areas are forecast
to be VFR throughout the TAF period.


&&

.MARINE...Northerly winds are expected to remain generally light
into Tuesday morning. Tuesday afternoon the winds in the lee of Cape
Mendocino are expected to increase to around 15 to 20 with generally
lighter winds elsewhere. These localized winds will once again bring
some steep northerly waves around 2 feet. The 10 second wave is
expected to continue around 4 to 5 feet. Late Tuesday night and
Wednesday northerly winds are expected to increase again. Currently
they are expected to be around 10 to 20 in most areas with gusts to
35 kt in the lee of Cape Mendocino. Small craft advisories will
likely be needed in at least some of the zones. These stronger winds
are expected to increase through at least Saturday before they may
start diminishing. The seas are expected to be dominated by short
period wind driven waves building to around 8 feet on Friday.
Starting Thursday the models are showing there may also be a small
south to southwest long period wave. MKK


&&


.FIRE WEATHER...A warming and drying trend has begun for the area
as high pressure strengthens from the Four Corners region. Winds
will be diurnally driven with westerly afternoon breezes that will
be gusty at times. The Minimum RH will drop to the low teens to
single digits starting Thursday as the heat intensifies and
overnight offshore winds strengthen. The hot and dry conditions with
some poor overnight recoveries will carry through the weekend. The
Four Corners region high will tap into monsoonal moisture at the end
of the week. Models clip our area with some of this moisture late
Friday and through the weekend. Currently, the moisture quality and
instability look too low to raise thunderstorm chances, but this
will have to be watched closely with the dry surface conditions and
likeliness of little to no precipitation from anything that forms.


&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
None.
NORTHWEST CALIFORNIA COASTAL WATERS...
None.
&&

$$

NOTE: The full forecast discussion is now regularly issued between
10 am/pm and 1 pm/am. Additional updates will be issued as needed.

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