848
FXUS66 KEKA 071139
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
439 AM PDT Tue May 7 2024

.SYNOPSIS...A significant pattern change from the cool, wet, winter-
like conditions is currently underway. A building expansive Pacific
ridge of high pressure will bring quickly warming temperatures and
strengthening N to NE winds. This combination of elements will allow
for unseasonably warm temperatures closer to the coast.


&&

.DISCUSSION...In the departure of a weak front, quickly clearing
skies allowed for temperatures in the drier interior valleys to drop
to chilly, frost producing temperatures this morning. With increasing
subsidence from building high pressure, and clearer skies, more
frost development can be expected overnight. The expansive Pacific
ridge will begin quickly amplifying today, and this strengthening
will continue through late in the week. Outside of the immediate
coast, temperatures will be noticeably warmer today for most.
Northerly winds will be increasing today, and by the afternoon,
gusts of 25 to 35 mph are forecast for the exposed coastal areas.
Interior ridgetop northeasterly winds will ramp up tonight, and
will become strong (gusts over 50 mph) from southern Trinity
southward, particularly over the highest ridges of Lake County
through Thursday morning.

The northerly breezes will be of similar strength on Wednesday as
the high further amplifies and an upper trough cuts off and
retrogrades west into the Great Basin. This will strengthen
offshore winds on Thursday/Friday when the warmest temperatures
are expected to the coast. Ensembles guidance holds near record to
record highs in the mid to upper 70s to the coast Thursday and
likely Friday. Interior valleys will rise to the upper 80s to low
90s. Given the setup and models` difficult ability to resolve the
far westward push of warmth from the offshore winds, leaned toward
the 75th percentile on Thursday for coastal highs when the most
pronounced offshore flow will develop. This will be quite a swing
from the below average temperatures of recent days, allowing
little time for acclimation. Ensembles generally hold the ridge
through the extended, with varying phases of amplification. /JJW


&&

.AVIATION...Northerly winds will begin to ramp up throughout today as
a ridging pattern continues to build into the region. Sustained
winds between 15 and 20 knots are anticipated for coastal terminals
this afternoon, with gusts to 25 and 30 knots likely. Northerly
winds for more interior areas will be weaker, but still could
potentially reach 10 knots by the afternoon. Elevated northerly
winds are expected to reemerge at the terminals each afternoon into
Thursday. Stronger winds will most likely keep coastal stratus to a
minimum.



&&

.MARINE...A northerly wind regime will become strong and dominant as
synoptic ridging sets up over the Western US. Winds will increase to
gale force by this evening. These northerly gales are expected to
last through Thursday. Gusts above 35 kts in all area waters are
forecast with some gusts in the northern outer waters reaching 45
kts by late Wednesday night. Wind waves out of the NW will be steep
at 9 to 10 feet in height and as many seconds in period. Seas are
anticipated to peak over 15 ft at 10-11 seconds out of the north by
Wednesday night. The thermal trough will build toward the coast late
in the week resulting in a weakening pressure gradient over the
waters and likely some weak southerly return flow near the immediate
coast.


&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
     Frost Advisory until 9 AM PDT this morning for CAZ102-
     105>108-110-111.

NORTHWEST CALIFORNIA COASTAL WATERS...
     Small Craft Advisory from 11 AM this morning to 9 PM PDT
     this evening for PZZ450-470.

     Gale Warning from 9 PM this evening to 3 AM PDT Thursday
     for PZZ450-470.

     Small Craft Advisory until 3 PM PDT this afternoon for
     PZZ455-475.

     Gale Warning from 3 PM this afternoon to 3 AM PDT Thursday
     for PZZ455-475.

&&

$$

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