Upper Lake, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

594
FXUS66 KEKA 160701
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
1201 AM PDT Wed Jul 16 2025

.SYNOPSIS...Inland temperatures continue trending down this week
while still remaining warm. The coastal stratus will become more
persistent over the coastal regions, lowering the daytime highs for
some areas.


&&

.DISCUSSION...A series of shortwaves moving through the Pacific
Northwest has weakened the ridge and brought slightly cooler (but
still hot) temperatures in the interior. High 80`s to 90`s are
forecast for much of the interior, with the highest temperatures
found in Trinity County and northeastern Humboldt County. Along the
coast, the marine layer is limited to the lowest 1000 ft, and
rising, early this morning. The marine layer is expected to deepen
over the coming days as the ridge continues to weaken. Some areas
along the coast may see drizzle overnight and in the mornings.
Offshore eddies with relatively light winds are likely to reinforce
stratus, including during the day, for the immediate coastal areas.
Partial clearing is still possible in the afternoon, but likely
temporary.

The shortwave does introduce some elevated instability this
afternoon, mostly in Trinity County. Moisture remains limited and
there is still a good amount of CIN, so thunderstorms are unlikely
(5-10% chances), but some cumulus is possible. There is a similar
setup Thursday afternoon. Instability will improve air quality in
the afternoon, except immediately downwind from the fire.

A similar pattern remains in place for much of the week with a
series of shortwaves moving into the Pacific Northeast. This will
keep temperatures moderated in the 90`s. By Thursday, NBM
probabilities of triple digits in Trinity and northeast Humboldt
fall off to less than 30% into the weekend. JB


&&

.AVIATION...(06Z TAFs) Coastal stratus has returned to coastal
terminals bringing a return to IFR/LIFR conditions as a strong
surface inversion traps moisture close to the terminals. Coastal
stratus is expected to erode to the coast by Wednesday afternoon and
then fill back in by Wednesday evening. Inland, VFR conditions are
expected with potential for smokey visibilities as well as light
surface (<10kt) and elevated winds (<15kt) in Trinity, interior
Humboldt and NE Mendocino counties.


&&

.MARINE...Small craft conditions continue to ease into early
Wednesday morning. As these winds diminish, the steep wind driven
seas are forecast to weaken, as well, leading to calm conditions
Wednesday. Stronger southerly winds are expected directly offshore
and north of Cape Mendocino Wednesday. Overall, however, moderate
breezes are expected from Wednesday through Friday. Fog and stratus
is to be expected as well with potential degraded visibilities
through the next 24hrs, especially at nighttime and in the early
mornings.


&&

.FIRE WEATHER...Some moisture and instability aloft will bring a
5-10% chance for dry thunderstorms in northern Trinity County this
afternoon and evening and again Thursday. Min RHs remain low, in the
teens and 20s, while overnight recoveries remain good. A weak
shortwave trough will increase southerly to southwesterly winds
locally this afternoon in Lake and Mendocino counties. Inland
temperatures will inch slighlty higher late this week and through
the weekend. RHs are likely drop to drop slightly with increasing
westerly winds through that period.


&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
None.
NORTHWEST CALIFORNIA COASTAL WATERS...
     Small Craft Advisory until 3 AM PDT early this morning 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.

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