Helena, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

480
FXUS66 KEKA 040702
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
1202 AM PDT Mon May 4 2026

.SYNOPSIS...Showers move south and taper off today into Tuesday. A
few thunderstorms are possible in Trinity County this afternoon and
evening. Warmer and drier conditions build midweek.


&&

.DISCUSSION...Thunderstorm activity has waned into the early morning
hours. Lingering showers will generally shift southward today with
rain likely only in Mendocino & Lake Counties by the afternoon.
Cloud cover and lingering moisture will keep interior temperatures
cooler, with most valleys in the 60s. There is around a 15-20%
chance for thunderstorms this afternoon and evening in the Trinity
Horn, and low chances (10-15%) to the south in interior Mendocino
and northern Lake Counties. Confidence is low as cloud cover and
cooler temperatures may keep thunderstorms from forming.

Drier conditions will quickly return by Tuesday. That said, there is
a very slight (10%) chance of some weak lingering thunderstorms over
the interior on Tuesday. Benign and weak high pressure will build
late in the week, bringing slightly warmer than average temperatures
but otherwise dry, seasonable, and calm weather. There is chance for
the marine layer to finally clear out around Wednesday before
rebounding later in the week as a marine inversion reforms under the
interior heat. /JHW/JB


&&

.AVIATION...IFR to MVFR ceilings are likely across the
terminals through sunrise as the deep marine layer remains steady.
Thunderstorm activity will also ease, but lingering showers will
continue through the day and move southward. By the afternoon,
showers will only be likely Mendocino & Lake. MVFR ceilings are
likely to remain through the day as coastal stratus persists and
showers continue at UKI. A brief rise into VFR is possible late
afternoon. JB


&&

.MARINE...A long period northwest swell has filled in on Sunday,
peaking at around 8 ft at 15 seconds. Winds have generally turned
light and southerly across the area. A few areas of brief gusty
winds, up to 20 kts, are possible north of Cape Mendocino early this
morning as stronger showers move over the waters. These will subside
by sunrise. Seas will generally ease over the coming days as winds
remain light. Winds turn northerly Tuesday and Wednesday, but remain
fairly light at around 5 to 15 kts, with the highest winds south of
Cape Mendocino. Combined seas remain mild at around 4 to 7 ft, with
a mix of short period waves of around 3 ft and mid and long period
NW swells of up to 5 ft. JB


&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
None.
NORTHWEST CALIFORNIA COASTAL WATERS...
None.
&&

$$

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