Fields Landing, California Weather Forecast Discussion

418
FXUS66 KEKA 070826 CCA
AFDEKA
AREA FORECAST DISCUSSION...CORRECTED
National Weather Service Eureka CA
126 AM PDT Sun Sep 7 2025
.SYNOPSIS...Dry weather with seasonable temperatures today. Wet
weather and possible thunderstorms Monday. Chance for rain and
possible interior thunderstorms Tuesday through Thursday.
&&
.DISCUSSION...
Shortwave trough that triggered a few thunderstorms in Trinity
County yesterday afternoon and evening has scooted off to the
northeast. A deeper and wetter trough outside 130W will slowly
advance toward the North Coast this afternoon through Monday
morning. Bulk of rain and convective activity with this next
trough will arrive on Monday. Generally light to locally moderate
rainfall is forecast on Monday, however there is a 20% chance of
isolated thunderstorms and a 10% chance for heavier rain rates
(>0.25in/hr) due to steep lapse rates associated with cold air
aloft for mainly the coastal ranges. We will post a graphic of
estimated rain amounts for Monday.
Tuesday and Tuesday night, the upper level trough settles over
the region. The potential for moderate to heavy rain is forecast
to diminish. Confidences for thunderstorms remain low for Tuesday
afternoon and evening.
Another shortwave trough will dive southward along the West Coast
on Wednesday. The GFS and ECMWF indicate an increase in precipitation
across the interior Wednesday afternoon and evening. The GFS
sounding shows increasing instability and steep mid level lapse
rates during this time period. Thus, there is a slight chance
(15%) of thunderstorms for the interior on Wednesday, especially
for Trinity County. On Thursday, wrap around precipitation will be
possible for Trinity, eastern Mendocino and northern Lake. Once
again deterministic model soundings indicate potential for storms.
Otherwise, drier and warmer conditions are anticipated Thursday
into Friday as ridge builds offshore. Another trough approaches
the coast by next weekend and appears to split or develop into a
cut-off. Forecast confidence this trough or cut- off low will
generate more precip or storms remains very low at the moment.
&&
.AVIATION...
(06Z TAFs)...A deep marine layer continues to develop over the
coast into Sunday morning. Mostly MVFR conditions are expected for
ACV and CEC, but borderline IFR ceilings could develop early
Sunday morning. There could be drizzle into Sunday morning associated
with the approaching trough. Winds will remain relatively light
with mostly onshore flow after sunrise. With the deep marine layer,
there is a non-zero chance for MVFR conditions to develop for UKI
around sunrise. Confidence is low, but there is still the possibility
of this occurring.
&&
.MARINE...
The marine forecast remains on track with recent buoy observations
confirming expected trends. Winds continue to be southerly while
speeds will gradually increase into Sunday ahead of the approaching
frontal system, though winds are expected to remain below 15 knots.
A couple of swells are worthy of mention. A mid-period west to
northwest swell and a long-period southerly swell. Combined seas
will be relatively calm, generally 3 to 4 feet. Conditions are
expected to remain well below Small Craft Advisory criteria through
the weekend. However, two primary hazards exist: patchy dense fog
may develop into Sunday morning, reducing visibility for mariners.
Secondly, the frontal passage on Monday will bring a chance (15-25%)
of thunderstorms, especially for the waters north of Cape Mendocino.
Mariners should be aware of the potential for erratic, gusty winds
and dangerous lightning with any storms that develop.
&&
.FIRE WEATHER...
Dry weather and near normal temperatures are expected today.
Generally, onshore westerly breezes are expected again this
afternoon. Cooler temperatures, higher relative humidity, and a
chance for wetting rain is expected Monday. Below normal
temperatures and a chance of rain and interior thunderstorms will
continue Tuesday through Thursday as an upper level low slowly
moves across the area. A warming and drying trend will be possible
on Friday, however another trough may bring cooling and more
showers next weekend.
&&
.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

NWS EKA Office Area Forecast Discussion