291
FXUS66 KEKA 200732
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
1232 AM PDT Mon Jul 20 2026

KEY MESSAGES...

* Warmer temperatures are bringing minor to moderate HeatRisk

* Possible showers and thunderstorms across the interior through
  Wednesday.

.SYNOPSIS...Above normal interior temperatures continue today.
Monsoonal and tropical moisture has arrived, bringing chances of
showers and thunderstorms early to mid next week.


&&

.DISCUSSION...High pressure continues to build over the area,
bringing warm interior temperatures into the 90s to just over 100 to
most interior valleys. Minor to locally moderate HeatRisk is
expected with this heat. Hazy skies are possible from fires in
southern Oregon and northern California, but impacts are expected to
be minor.

Monsoonal moisture has returned. While moisture aloft will be
plentiful with PW of over 1 inch, instability is still meager. Some
high resolution models do show a little instability (around 100-300
J/kg of CAPE) tonight into early Monday, and again Monday afternoon.
Thunderstorm chances remain low at around 10-15% and one of the
biggest uncertainties is the timing and location of these storms,
should they form. Dry low levels will evaporate most precipitation
and any thunderstorms are likely to be dry thunderstorms. A Red Flag
Warning has been issued for this dry thunderstorm potential.

Moisture from Tropical Storm Elida continues to stream in Monday
which will continue the threat for a few showers and thunderstorms.
This trend will continue through Wednesday with shower and
thunderstorm chances generally increasing each afternoon with
Wednesday having the highest chances. Still, chances are low at
around 15% mainly in Trinity County. Uncertainty remains high as the
path of the remnants of Elida will strongly influence what areas see
impacts. Some ensemble members show the center of the low very close
to the shore of the North Coast.

Increased cloud cover and weaker high pressure will nudge interior
temperatures closer to average, though most interior valleys will
still see 90s. Most coastal areas will see highs in the 60s with
overnight and morning stratus. /JB


&&

.AVIATION...Strands of moisture from the monsoonal origin are
keeping cloud cover and visibility low as the high pressure sinks
the layers towards the deck, stratifying clouds into low ceilings
well into Monday. LIFR for the coastal terminals began during
daylight hours Sunday early evening, showing the magnitude of the
cloud layer and moisture advection. With the Tropical Storm Elida to
the south we can expect several days of socked in/low vis flight
conditions. Tempo groups are in place for the TAFs for 1/4mile fog
but there have been periods of M1/4 and less for visibility at KACV
and possible at KCEC as well. The southerly flow usually brings this
type of cloud regime if moisture is available. /EYS


&&

.MARINE...Northerly winds continue to gradually ease and move
farther off the coast. Still, the outer waters remain hazardous to
small crafts through Monday afternoon and so the SC.Y has been
hoisted. Winds continue to ease Monday with peak gusts of 15 kts or
below likely for all waters. Nearshore winds will be relatively
light, and could be southerly along the coast as eddies form. Winds
will generally be mild for much of the week.

Seas remain characterized mainly by decaying northerly wind waves
and small mid to long period northwesterly and southerly swells.
Steep seas will slowly ease in the outer waters today and be
relatively mild by Monday. A larger southerly swell, peaking at 4-5
ft from Tropical Storm Elida arrives Monday and continues for much
of the week. With relatively light winds, seas could be dominated by
this swell. This could create some larger breakers than usual on the
southern facing beaches, especially south of Cape Mendocino.


&&

.FIRE WEATHER...Afternoon RH continues to be low with most
interior areas seeing teens and 20s. High temperates return closer
to average early week as high pressure weakens. Winds generally
remain light and terrain driven. Monsoonal moisture has arrived
and will continue to influence the area through Wednesday. There
will be multiple low chances (15% or less) of thunderstorms for
the interior areas tonight through Wednesday. Dry low levels will
limit precipitation from reaching the ground.


.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
     Red Flag Warning until 6 PM PDT this evening for CAZ403-406-
     409>412.

NORTHWEST CALIFORNIA COASTAL WATERS...
     Small Craft Advisory until 8 AM PDT this morning for PZZ450.

     Small Craft Advisory until 3 PM PDT this afternoon for
     PZZ470-475.

&&

$$

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

Visit us at https://www.weather.gov/eureka

Follow us on Facebook and Twitter at:
https://www.facebook.com/NWSEureka
https://www.twitter.com/NWSEureka

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