Area Forecast Discussion
Issued by NWS Eureka, CA
FXUS66 KEKA 301107
AREA FORECAST DISCUSSION
National Weather Service Eureka CA
407 AM PDT SAT JUL 30 2016
.SYNOPSIS...A slight cooling trend can be expected through early
next week as an upper trough moves through the Pacific Northwest.
A shallow marine layer will persist along the coast, with
nocturnal fog and stratus and mild temperatures.
.DISCUSSION...Typical summer conditions are expected for the next
week with highs in the 60s near the coast and upper 80s to near 100
degrees in the interior valleys. Small fluctuations in temperatures
are expected with the "coolest" days occurring early next week as
an upper trough passes through the Pacific Northwest. Both the GFS
and ECMWF are trending toward the development of a baggy trough
along the Pacific Northwest coast for late next week, which would
result in less of a chance for a return to lower 100 degree
temperatures than thought a few days ago. Though there is a very
slight possibility of the development of a shower over the Trinity
County horn this afternoon, in general dry conditions will persist
for the next week across all of Northwest California.
Clouds will continue to impact coastal areas throughout the week
with the best chances for low clouds and fog during the overnight
and morning hours. Northerly winds will mix dry air into the marine
layer during the late mornings and afternoons which should bring at
least some partial clearing each day. However, winds will be
quite light or even southerly along the Mendocino coast over the
weekend. This may allow the fog to persist along the immediate
coast instead of mixing out in the afternoon hours. The tightest
coastal pressure gradient will adjust its orientation from over
waters off the Humboldt/Del Norte coastline to the entire
Northwest California coast by early to mid next week. This will
bring back the northerly winds along the Mendocino coast and thus
better chances for more sunshine. /RPA
.AVIATION...Ceilings and VSBYs have been falling through the night
at both KACV and KCEC as a shallow marine layer clings to the
shoreline of northern California. Light drainage winds have been
keeping the fog (FG) and stratus subdued around KCEC as of 4am PDT.
Stratus and fog should dissipate quickly there shortly after sunrise.
Also, VSBYs probably will not be as low as yesterday. Expect the
bulk of stratus and fog to dissipate by mid to late morning at both
airports as the land mass heats up. Light onshore flow in the
afternoon will prime conditions for redevelopment and expect flying
conditions to deteriorate once again this evening after solar
heating abates. The marine layer will NOT push very far into the
coastal river valleys today or tonight. VFR will continue to reign
at KUKI through the period.
.MARINE...Strong north winds and large steep seas will persist
across the outer waters through the weekend as high pressure
interacts with a thermally induced trough over the interior.
The strongest winds will continue to be in the northern outer
waters. ASCAT pass indicated a swath of northerly winds at 35kt.
Models continue to trend upward today and northerly wind are
expected to remain at full GALE through Sunday. South of the Cape 10
to 60nm from shore, GALE conditions will be marginal, however seas
will be large and very steep.
Buoys have been reporting seas around 11 ft with periods at 9-10
seconds early this morning. Wave heights will probably remain steady
or increase today. Conditions will most likely worsen as north winds
of 30-40kt offshore send another surge of steep waves into the inner
waters north of the Cape tonight.
Conditions should ease up slightly offshore early next week, however
the NWPS model continues to indicate rough and steep northerly waves
with near GALE conditions through mid week. The strongest winds may
end up shifting south of the Cape as the thermally induced trough
retreats southward. Rough ocean conditions will most likely continue
into the latter portion of the week.
NORTHWEST CALIFORNIA COASTAL WATERS...
Small Craft Advisory until 5 AM PDT Thursday for PZZ450-475.
Gale Warning until 8 AM PDT Monday for PZZ470.
Visit us at http://WWW.WEATHER.GOV/EUREKA
Follow us on facebook and twitter at:
FOR FORECAST ZONE INFORMATION
SEE FORECAST ZONE MAP ONLINE: