Orleans, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

848
FXUS66 KEKA 281928
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
1228 PM PDT Wed May 28 2025

.SYNOPSIS...Warmer weather will continue through late week. Hot
temperatures Friday and Saturday for the interior before a quick
trend downward Sunday into next week. Strong northerly winds will
develop over the weekend.

KEY MESSAGES:

-Moderate to some areas of Major HeatRisk are forecast Friday and
Saturday for the interior

-85% to 95% chance for high temperatures to exceed 100 F in the
 warmer interior valleys on Friday, with some higher heat index
 values

-50% to 75% probability for high temperatures to exceed 100 F in the
warmest interior valleys on Saturday

-Strong to very strong northerly winds over the weekend with
 moderate to high chances for gusts over 40 mph Sunday (53%-67%)


&&

.DISCUSSION...As a shortwave disturbance extends along CA,
coastal stratus protrudes will inland today with a deepened marine
layer. There have been hints that this feature could generate
enough forcing and elevated moisture/instability for some
convective showers and perhaps low-end chanced for a thunderstorm
in NE Trinity COunty, but chances for this outcome have continued
to lower with highly limited available moisture. SREF has lowered
chances to 5%.

A weak trough and weak, decaying front will clip the region late
tonight and Thursday, increasing cloudcover. Any precipitation that
forms along the front will remain north or over the ocean, or there
may be trace amounts of light drizzle. The ridge is then forecast to
amplify much higher Friday and Saturday with triple digit heat
forecast and highly probable. NBM currently now holds a 85% to 95%
chance for high temperatures to exceed 100 F Friday in the warmer
interior valleys. A shortwave trough and front will then begin to
approach on Saturday, and this will being to lower daytime highs,
particularly closer to the coast as westerly flow pulls in
marine- influenced air. NBM has lowered chances to 52% - 75% for
high temperatures to exceed 100 F in the warmest interior valleys
Saturday.

The combination of the forecast high temperatures with some warmer
overnight lows, and a lack of acclimation to this relatively
early- season heat wave will create widespread Moderate to some
areas of Major HeatRisk. A more humid airmass will raise dewpoints
closer to the coast and through interior Humboldt and Mendocino
counties Friday afternoon, and this will contribute to heat index
values as high as 107. Caution is advised with outdoor activity.

Ensembles and the clusters continue to depict high confidence for
troughing to dig in from the north late Saturday through Sunday,
quickly lowering temperatures. There is questions in the depth of
this trough, and the timing of a secondary cold upper low. This
could mean an even more dramatic cooldown of temperatures, late
season precipitation or even thunderstorm activity depending on how
the low evolves. The Climate Prediction Center is leaning towards
above normal precipitation for day 6-10 over CA.

Strong to very strong northerly winds are beginning to take shape in
the forecast over the weekend, but the strength of these winds will
also be determined by how the low evolves. NBM holds moderate to
high chances for gusts over 40 mph Sunday (45%-57%) for much of the
coast. The more exposed coastal headlands have a high chance for
exceeding 40 mph gusts. There are also decent probabilities for
gusts of 45 mph for the the higher coastal ridges and around
Crescent City (67%). Monday looks to continue to be windy.
Looking at the ensemble members and spread for wind gusts,
advisory level conditions may be reached. JJW


&&

.AVIATION...Stratus has begun to lift this morning as a weak front
approaches the coast. This is acting to weaken the inversion and
deepen the marine layer, both of which have lifted CIGS into the
MVFR category. Some breaks in the clouds are expected for the
coastal areas this afternoon, but with the approaching trough it
doesn`t look they will stay clear very long, with more MVFR
to IFR stratus expected along the coast tonight. MKK


&&

.MARINE...The northerly winds continue to weaken as a very weak
front approaches the area. This afternoon the front brings some
light southwest winds into the outer waters, mainly north of Cape
Mendocino. In addition to this the main wave in the waters is a 5 to
6 foot wave at 10 seconds, and this generally expected to continue
through Thursday.

The front is expected to pass late tonight. Thursday morning
immediately behind the front winds are expected to rapidly increase
to 15 to 25 kt, spreading across most of the outer zones by the late
afternoon. Winds will remain fresh to strong Friday. Saturday strong
to near gale force winds are possible, with these most likely south
of Cape Mendocino. Saturday night and Sunday strong gales are
possible. Confidence is increasing on these as model agreement
continues to improve. The strongest winds are expected to be Sunday
afternoon or evening. There is some model guidance, including the
ECMWF model, showing that these will come in slightly later on
Sunday and last through Sunday night. These differences becomes
bigger on Monday. MKK


&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
     Heat Advisory from 11 AM to 9 PM PDT Friday for CAZ105-106-
     110-113.

     Heat Advisory from 11 AM Friday to 10 PM PDT Saturday for
     CAZ107-108-111-114-115.

NORTHWEST CALIFORNIA COASTAL WATERS...
     Small Craft Advisory from 9 PM Thursday to 11 AM PDT
     Saturday for PZZ470.

     Small Craft Advisory from 4 PM Thursday to 11 AM PDT
     Saturday 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