971
FXUS66 KEKA 101920
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
1220 PM PDT Sun Aug 10 2025

.SYNOPSIS...Hot and drier weather conditions expected through
Tuesday. Moderate to localized Major HeatRisk through Monday.
A gradual cool down is expected by mid to late next week.

&&

.KEY MESSAGES...

* Very hot weather with temperatures in the triple digits today
  and Monday.

* Moderate to localized Major HeatRisk through Monday across the
  interior, bringing the risk of heat-related illness for anyone
  without effective cooling and/or adequate hydrate.

&&

.DISCUSSION...Satellite is showing stratus blanketing the coastal
waters and areas of the coast late this morning. Stratus has already
started to pull away from the coast, but more marine influence will
contribute to slightly cooler high temperatures in the coastal areas
today. Inland, temperatures remain hot. The Trinity River valley is
the warmest area, with high temperatures today forecast to be
between 105 and 115. Areas of interior Mendocino and interior Del
Norte could see highs between 100 and 105F. This heats brings a
major risk of heat-related illness for anyone without effective
cooling and/or adequate hydration.

The highest heat shifts eastward Monday, bringing temperatures down
a few degrees, but still conditions remain hot in the interior.
Areas of northern Trinity and northeast Humboldt are still forecast
to see high temperatures between 100 and 110F. The Heat Advisory
remains in effect Monday in northeast Humboldt and Northern Trinity
as these temperatures still do present a moderate to major risk for
heat-releated illness. Onshore flow will keep coastal temperatures
moderated, largely in the 60`s.

Tuesday, the ridge break down and a shortwave will gradually squeeze
down the coast bringing an end to the worst of the heat and
increasing onshore flow. However, temperatures are expected to
remain in the upper 90`s to 105, with the highest temperatures in
Trinity County.

Ensemble clusters and deterministic model guidance are showing an
upper level trough from the northeast Pacific driving southward
along the coast on Wednesday and settling over the area late next
week. This will bring an enhanced onshore winds and a deepening
marine layer with coastal stratus. While unlikely, some ensemble
members are showing a trough digging farther south into northern
California this weekend, and the wettest members do show some
potential for rain and possibly thunderstorms in the interior. JB/ZVS


&&

.AVIATION...Coastal terminals are currently forecasted VFR through
the daylight hours. A southerly surge of coastal stratus is expected
to bring LIFT conditions with an 80% probability to the coast late
afternoon/early evening today. Expect light winds from variable
directions due to the southerly surges and eddies forming along
coastal terminals. Inland, VFR is expected with diurnal heating
driven winds, primarily from the WNW today before calming tonight.
Height density issues continue to be possible as inland temperatures
rise to over 100F this Sunday, Monday, and Tuesday.


&&

.MARINE...The recent strong northerlies continue to move further
offshore today into the far outer waters, however, steep wind wave
seas are still expected through the day as waves slowly subside.
Gentle to moderate southerly winds have filled into the coast,
accompanied with areas of dense fog leading to visibilities <1/2NM.
Other than diminishing northerly wind waves, two minor mid period
swells will fill in today, one from the south-southwest and another
from the northwest. These swells have the potential to create square
wave pattern due to the perpendicular wave directions creating
possible grid-like patterns. Conditions remain mild early this
coming week with breezy northerlies likely to return by
Wednesday/Thursday.


&&

.FIRE WEATHER...Hot and drier weather conditions are expected
through Tuesday. Very dry daytime RH`s values in the single digits
and teens percent will continue through Monday. Breezy offshore
winds have generally eased in the higher terrain, but conditions
remain hot and dry. RH recoveries remain poor on the ridges (20-
40%). Winds are expected to be light during the day, yet westerly up
valley winds may become breezy each afternoon and evening. Dry
weather will continue next week, but with a gradual cooling trend
and improved RH recoveries by mid to late next week. On Thursday,
elevated fire weather threat should be possible with enhanced
onshore winds and low daytime RH in the teens and 20`s, especially
in Lake County. /ZVS


&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
     Heat Advisory until 11 PM PDT this evening for CAZ102-105.

     Heat Advisory from 9 AM to 11 PM PDT Monday for CAZ105.

     Heat Advisory until 11 PM PDT Monday for CAZ107.

NORTHWEST CALIFORNIA COASTAL WATERS...
     Small Craft Advisory until 11 PM PDT this evening for
     PZZ470.

     Small Craft Advisory until 3 PM PDT this afternoon for
     PZZ475.

&&

$$

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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https://www.weather.gov/images/eka/zonemap.png