Helena, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

987
FXUS66 KEKA 090704
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
1204 AM PDT Wed Jul 9 2025

.SYNOPSIS...Near or slightly below normal temperatures are
expected again Wednesday. Warming is expected again Thursday with
additional warming Friday and hot weather continuing into early
next week.


&&

.DISCUSSION...The center of the upper low currently moves over the
area. This has the potential to bring some thunderstorms to the
area. The models aren`t explicitly outputting thunderstorms, but
there is some elevated instability. This, combined with the dynamics
of the low and steep lapse rates aloft may bring some nocturnal
thunderstorms.

Wednesday during the day the upper level low is expected to move off
to the east and we will be in northwest flow. It looks like the
threat for thunderstorms will diminish through the day light hours
on Wednesday.

Wednesday night into Thursday morning offshore flow is expected in
Humboldt and Del Norte counties. This should diminish the marine
layer and allow skies to clear. Thursday is expected to be the
transition day with warmer temperatures, but highs are expected to
remain in the 90s in most inland areas with low to mid 60s possible
along the coast. Friday additional warming is expected with highs
climbing over 100 in many of the valleys. The coast may see highs in
the middle to upper 60s with continued offshore flow. This is
expected to bring moderate to major heat risk to many of the areas.
This heat is expected to persist through the weekend in some of the
interior areas. A heat advisory may be needed in some of the more
persistently hot areas. There is some uncertainty on how much the
valleys will cool off at night and that could mitigate the impact of
the heat. MKK


&&

.AVIATION...Mostly IFR conditions are expected along the North Coast
into Wednesday morning. The upper low spinning over head has
aided in the deepening of the marine layer, as well. With
southerly flow up the Russian River Valley, there is a possibility
of MVFR ceilings for KUKI a few hours before sunrise Wednesday.
There appears to be little chance for clearing through the day
Wednesday for coastal terminals with ceilings most likely lifting
into MVFR range by the afternoon. /JLW


&&

.MARINE...Light winds and low seas are currently dominating the
marine environment as an upper low spins over the coastal waters.
This low will move inland Wednesday allowing surface high pressure
to re-build toward the Northwest California coast over the Eastern
Pacific. This will enhance the pressure gradient and once again
strengthen the northerlies. Near gale to gale wind gusts are
possible Thursday through Saturday, most likely over the outer water
zones, pulling into just the northern waters this weekend as the
thermal trough builds north over land. Steep short period seas will
build in response to the gale northerlies. /RPA


&&

.FIRE WEATHER...High temperatures in the 80`s and 90`s are expected
for most of the interior on Wednesday. The marine layer is expected
to remain deeper through Wednesday morning as an upper-low moves
past the area, bringing slightly higher afternoon RHs. As this upper
low moves overhead there is the potential for thunderstorms to move
across Humboldt, Del Norte and Trinity counties early Wednesday, yet
as of writing this no storms have been seen via satellite/radar.
Confidence on these storms manifesting remains low and the better
chance for Thunderstorms remains to the north of the area, with
storms seen over NE Oregon. Overnight recoveries generally remain
good aside from the exposed ridges in the thermal belt.

Much hotter temperatures and drier humidity are likely in the
interior late this week. Thursday and Friday mornings offshore flow
will bring poor recoveries to the higher elevations and may push the
stratus off the coast. Triple digit temperatures are likely in most
of the interior valleys by Friday with very low afternoon RHs and
moderate overnight recoveries. JB


&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
None.
NORTHWEST CALIFORNIA COASTAL WATERS...
     Small Craft Advisory from 3 AM to 11 AM PDT Thursday for
     PZZ455-470.

     Gale Watch from Thursday morning through Thursday evening
     for PZZ455-470-475.

     Small Craft Advisory from 9 PM this evening to 11 AM PDT
     Thursday 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