367
FXUS66 KEKA 300832
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
132 AM PDT Thu Jul 30 2026

.KEY MESSAGES...

* Hot temperatures return late week and into the weekend, with
  hotter temperatures and widespread Moderate to locally Major
  HeatRisk early to mid next week

* Elevated fire danger returns late in the week and into next week
  with periods of breezy winds and increasingly hot, dry
  conditions.

* Westerly to northeasterly winds through the weekend and into
  Monday will bring the greatest fire weather risk.


&&

.SYNOPSIS...Temperatures begin trending hotter. Breezy afternoon
winds elevate fire danger in eastern Trinity, eastern Mendocino,
and Lake counties. Hot interior temperatures in combination with
periods of breezy winds through the weekend and into Monday,
further increase the fire weather risk.


&&

.DISCUSSION...An upper level trough over the Gulf of Alaska will
continue to affect weather patterns over Northwest California today
and tomorrow. Stratus is then expected to deepen and expand over
the coast and down coastal river valleys again overnight tonight.
Cooler than average temperatures will continue today and tomorrow
for the interior as the upper low affects the area. The rest of
this week and into the weekend, northerlies will continue to
strengthen over the ocean restarting upwelling and leading to the
usual cooler near shore ocean temperatures. This will cause cool
air advection into coastal areas which will help trend coastal
temperatures back towards normal. A pronounced shortwave
perturbation will advance over N CA Thursday. Moisture and
instability will be very limited, so only mid to high level clouds
should result. This feature may act to disrupt the inversion and
clear out the low clouds Thursday afternoon.

A Four Corners/Desert Southwest dome of high pressure will then
begin to strengthen Thursday. The 500mb ridge will continue to
strengthen, reaching 597 to up to 600dm by Friday, and this will
translate to hot interior temperatures. Temperatures will likely
reach or exceed 100 in some of the warmer valleys Friday and through
the weekend as a result. Probabilities for interior temperatures
over 100 further increase going into next week, with high chances
(60 to 80%) for temperatures over 100 by Monday, and moderate
chances (40%) for temperatures over 104 Tuesday of next week.
Currently, this heat setup looks to bring widespread Moderate to
locally Major HeatRisk. There is a 30-50% chance for isolated
areas of Major HeatRisk Monday and especially Tuesday, though the
timing of peak heating may change.

Fire weather concerns will become elevated again with the duration
of the building heat along will periods of breezy conditions. See
the Fire Weather section below. /JJW /JLW


&&

.AVIATION...06Z TAFs.The influence of NE Pacific troughing
maintains a relatively deep marine layer for the season. A shallow
layer to LIFR levels may form overnight Wednesday, with bouts of
light drizzle and perhaps TEMPO fog.

A compact shortwave trough will push through Thursday afternoon, and
there are indications it could disrupt the inversion and aid in full
late afternoon, perhaps as early as the late morning hours. If
this occurs, it is uncertain how fast the stratus will return.
/JJW


&&

.MARINE...Northerly winds north of Cape Mendocino look to generally
remain below 20 kts through Friday. The focus of stronger
northerlies will remain around and south of Cape Mendocino.
Northerlies of 20-25 kts in these southern zones, locally with gale
conditions up to 30 kts around the cape, can continue to be expected
through Friday. Short period northerly seas will increase over the
waters while a small long period southerly swell slowly fades.

A ridge of high pressure will then strengthen through the weekend,
bringing increased chances for gale strength northerlies over much
of the waters. There is growing confidence for strong northerlies
with sustained gale strength winds of 34kts and gusts approaching or
exceeding 40 kts as troughing to the north squeezes against the
strong ridge to the SE. Subsequent steep seas over 15 ft will
develop over the weekend and into early next week. Gale conditions
could start as early as late Friday in portions of the southern
zones. /JJW


&&

.FIRE WEATHER...Afternoon westerly breezes will likely bring
isolated areas of enhanced fire weather danger and perhaps brief
critical conditions locally. Overnight recoveries will begin to
decline Thursday and Friday with building heat and drying conditions
from a strong Four Corners/Desert Southwest ridge of high pressure.
Triple digit high temperatures can be expected in the interior
Friday and through the weekend. Chances for temperatures over 100
increase Monday and especially Tuesday of next week. Min RH will
drop back into the mid to low teens Thursday and Friday.

A trough of low pressure will move eastward over the Pacific
Northwest over the weekend, squeezing a strong pressure gradient
against the existing ridge to the SE. Stronger afternoon westerly
winds will develop as a result, with chances for gusts over 25 mph
increasing to 50 to 70% for a good portion of the interior Saturday
afternoon. A robust burst of dry NE winds will likely follow to
departing trough later Sunday through Monday over the interior
ridges of Trinity, Humboldt and Del Norte counties.

Minimum RH is expected to come up slightly with the westerly flow
Saturday. RH will trend much lower, to the low teens and likely some
single digits through Monday, and then remaining dry into mid next
week /JJW


&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
None.
NORTHWEST CALIFORNIA COASTAL WATERS...
     Small Craft Advisory until 5 AM PDT Saturday for PZZ455-475.

&&

$$

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