Whitethorn, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

650
FXUS66 KEKA 211230
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
530 AM PDT Sat Jun 21 2025

.SYNOPSIS...Stronger west and northwest winds expected to continue
for the interior through Saturday. Below normal temperatures are
expected for the interior today. Temperatures warm Sunday and
remain near seasonal norms next week.


&&

.UPDATE...Temperatures haven`t fallen as much as expected across
the interior valley locations. This is due to two factors: 1)
greater cloud cover than anticipated and 2) the atmosphere did
not de-couple and wind has been persistent. Thus, frost is no
longer expected and the frost advisories have been cancelled.


&&

.PREV DISCUSSION... /issued 1252 AM PDT Sat Jun 21 2025/


KEY MESSAGES:

- Elevated to locally critical fire weather conditions through Saturday
  evening for Lake, eastern Mendocino and eastern Trinity
  Counties due to low RH`s and stronger northerly winds.

- Much cooler Saturday in the interior, followed by a warming and drying
  trend early to mid next week.

- Light rain in Del Norte and northern Humbodlt could linger
  into Saturday.

DISCUSSION...Radar returns show isolated showers, which have
become few overnight into Saturday and are expected to diminish in
frequency by Saturday evening. Concerns for elevated to locally
critical fire weather conditions are less than the previous 24
hours with RH values improving slightly. Timing for the
components do not align but are enhanced at opposing hours. Winds
may not line up exactly with low RH`s for 8 hours or more for a
red flag warning. Winds will lessen some, but remain gusty with
70-80% chance for gusts of 30 mph over the ridges Saturday
afternoon and evening.

An additional burst of light and isolated shower activity is
possible Saturday with wraparound moisture on the backside of the
trough. Clearing skies and lessening winds in the valleys will allow
for temperatures to drop to chilly levels in the interior under this
colder and drier airmass. A Frost Advisory has been hoisted for some
colder interior valleys. Areas where cloud cover lingers and winds
stay up will not likely reach frost criteria.

A warming trend is forecast early to mid next week with highs in the
lower to mid 90`s by Wed for the interior valleys. Also of note is
the possibility (currently 5% chance or less) for thunderstorms over
the interior mountains Monday afternoon as troughing and additional
shortwave energy remains over the region. Moisture looks very
limited at this time, but there is variability in model scenarios.

AVIATION...06Z TAF: A cold front will continue through the region
during this TAF period. Winds will remain elevated for inland
terminals aloft with gusty NW surface winds. Along the Humbodlt and
Del Norte coast, winds will be lighter and possible MVFR/IFR
conditions are expected into Saturday morning due to rain showers
migrating over terminal spaces. Along the Mendocino coast, winds
will be stronger with NW gusts up to 25kts, scattered cloud
coverage, and no rain expected.

Forecast confidence is high with inland terminals having breezier
than normal winds. Winds into Saturday will remain elevated due to
synoptic forcing instead of the usually diurnal heating. Along the
coast Del Norte and northern Humboldt coast, isolated rain showers
will continue east and taper off into early Saturday morning.

MARINE...As the low pressure system moves through the Pacific NW
region, northerly winds have calmed. However, northerlies will
increase again through Saturday afternoon and into Sunday as the low
moves inland. Gentle to moderate breezes are expected early Saturday
before increasing again in the southern waters. Winds are forecast
to be strongest off the coast of Fort Bragg with near gale to gale
force gusts Saturday afternoon. Small craft conditions are expected
in the southern outer waters, with more widespread gale conditions
in the southern inner waters with steep wind waves and gusty winds
up to 40kts possible in areas closer to the Mendocino coast. Breezy
north winds are expected to persist through this coming work week.

FIRE WEATHER...A low level northerly speed max (925mb) will
likely develop over the Sacramento valley and clip the eastern
peripheries of Mendocino and Lake Counties Saturday. Lower
overnight humidity and gusty N-NE winds are likely over the higher
terrain of Lake and eastern Mendocino (fire weather zones 264 and
277). Once again we may be flirting with locally critical fire
weather conditions Saturday, lasting into the evening hours. Our
neighboring NWS office in Sacramento has a Red Flag Warning out
for cured grassy fuels for elevations below 1000 feet. Otherwise,
daytime minimum humidities are forecast to trend drier over the
latter portion of the weekend (Sunday) into early next week as
temperatures increase each day and winds greatly ease.

Also of note is the possibility for thunderstorms over the
interior mountains through the end of the weekend and early next
week as shortwave energy remains. There is considerable model
variability. At this point, there is no compelling reason to
deviate from the National Blend of Model thunderstorm probability
(NBM) and chances currently look less than 5%.

&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
None.
NORTHWEST CALIFORNIA COASTAL WATERS...
     Gale Warning from 3 PM this afternoon to 11 PM PDT this
     evening for PZZ455.

     Small Craft Advisory from 3 PM this afternoon to 3 PM PDT
     Sunday 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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For forecast zone information
see the forecast zone map online:
https://www.weather.gov/images/eka/zonemap.png