246
FXUS66 KEKA 192134
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
234 PM PDT Sun May 19 2024

.SYNOPSIS...Northerly winds have ramped up this afternoon and will
continue this evening. Winds ease mid week with moisture approaching
the area via meridional flow as the high pressure backs off of the
coast. A series of upper shortwaves and associated weak fronts
accompany cooler temperatures. More substantial unsettled pattern
possible late week into next weekend.


&&

.DISCUSSION...Stout northwesterly winds have been building through
the day and will peak tonight. A surface high pressure of
anticyclonic rotation, sets up a steepening gradient with isobars
perpendicular to the coast line with mid and upper level ridging
pattern bringing northerly winds to bear on the PNW. High resolution
models have increased the magnitude in the latest model runs and
have verified, as observations have already met Wind Advisory
criteria (>39 kts) in the coastal Del Norte zones. With gusty
winds not expected to ease until the evening, A Wind Advisory has
been hoisted through 9 pm for coastal Del Norte. Exposed ridges
and headlands of Cape Mendocino will also see northerlies with
sustained winds around 30 kts and gusts exceeding 45 kts.

Model soundings show a dry vertical profile and with clear skies
expected, radiative cooling could lead to frost Monday morning for
the southern Humboldt and Trinity interiors. A slightly below normal
temperature trend may also lend to lower overnight temperatures.
HREF indicates a 30-40% probability for <36 degrees in eastern
Trinity and interior Humboldt counties, although probabilities for
temperatures <40 degrees are more widespread from interior Del Norte
to northern Mendocino counties. A Frost Advisory is in place for the
Humboldt and Trinity interiors for early Monday morning.

More persistent WNW flow is forecast by mid-week, enhancing BL
moisture and allowing for potential redevelopment of the marine
inversion as a transient ridge builds into the coast. Long range
models indicate a more progressive troughing pattern expected for
late this week into next weekend. /JMM /EYS

&&


.Aviation...Gusty northerly winds will help keep the terminals in
VFR throughout the TAF period. Gusts from 30 to 40 kts could be
possible along the coast with higher gusts more likely for coastal
Del Norte County. Into this evening the highest gusts will settle
down; however, along the coast and the ridges, northerlies will
still be about 10 to 20 knots. For more protected interior areas,
winds will calm overnight. Northerly winds are forecast to yet
again pick up late tomorrow morning for most of the region.


&&


.Marine...A thermal trough along the coast continues to produce a
strong pressure gradient that will persist through Monday
evening. As a result, northerly gales are expected in all zones
through Monday, producing hazardous 10-12 foot short period waves
across all zones. Steep and dangerous seas will continue into
early next week as gales persist. Significant wave heights to 15
feet at 10-11 seconds are expected. Current model guidance
indicates the strongest winds and wave response shifting to the
southern waters by Tuesday. Gales are expected to finally cease by
mid week as the coastal pressure gradient weakens, but a small
craft advisory may be warranted for the middle to end of the week.


&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
     Wind Advisory until 9 PM PDT this evening for CAZ101.

     Frost Advisory from 3 AM to 9 AM PDT Monday for CAZ106-108.

NORTHWEST CALIFORNIA COASTAL WATERS...
     Gale Warning until 9 PM PDT Monday for PZZ450-455.

     Gale Warning until 11 PM PDT Monday for PZZ470-475.

&&

$$

Visit us at https://www.weather.gov/eureka

Follow us on Facebook and Twitter at:
https://www.facebook.com/NWSEureka
https://www.twitter.com/NWSEureka

For forecast zone information
see the forecast zone map online:
https://www.weather.gov/images/eka/zonemap.png