FXUS66 KEKA 202152
AREA FORECAST DISCUSSION
National Weather Service Eureka CA
252 PM PDT Thu Sep 20 2018
.SYNOPSIS...High pressure offshore will maintain dry weather
through next week. Coastal clouds will become more widespread and
persistent this weekend, before another period sunny and potentially
warmer weather with offshore flow next week.
.DISCUSSION...As forecast, skies have cleared across all of northwest
California this afternoon, after just a localized area of broken
stratus around Humboldt Bay and the lower to middle Eel River this
A flat ridge aloft continues to build across our forecast area,
and in response, temperatures just inland from the immediate
coast are running 4 to 8 degrees warmer than this time yesterday.
The hottest interior valley locations will peak above 90 degrees.
While surface high pressure offshore is beginning to weaken, winds
over the coastal waters are still strong, and northerly breezes
are keeping exposed coastal areas cooler.
As a thermal trough remains situated near the coast under this flat
ridge aloft, weak offshore flow will continue to rule tonight
into Friday morning. This will keep the marine layer shallow, with
only very limited stratus and fog development around the lower
Eel River and Humboldt Bay again late tonight into Friday morning.
Friday will otherwise turn out mostly sunny once again, with
afternoon temperatures pretty close to today's values, peaking in
the low 90s across the hotter interior valleys.
The ridge aloft will start to weaken and transition eastward on
Friday as a new trough approaches the Pacific Northwest coast.
Temperatures will probably remain above normal in the interior on
Friday. A dry front will move across the area Friday night resulting
in a return of coastal low clouds. No rain is expected for NW
California from this front, though patchy drizzle will be possible.
A push of marine air behind the front will probably bring cooling
to interior Humboldt and Del Norte counties this weekend.
A dry weather pattern is expected to persist through next week.
Temperatures will likely warm up again early to mid next week as
an upper ridge rebuilds and an offshore flow pattern emerges. The
details are still a bit uncertain, but this pattern will have the
potential to produce even hotter temperatures inland than what we
are seeing this week, with 70s even possible along the immediate
.AVIATION...Conditions along the coast overnight were mostly SKC,
except for areas of stratus clouds near the EEL Delta to
Patrick's Point. This stratus area was somewhat unhurried to
dissipate compared to the previous morning. A brief hour of IFR
Cig/Vis occurred at CEC. Even after midday, stratus was still
hovering over Humboldt Bay-Trinidad with mostly stratus strands
moving in and out of ACV, and resulting in occasional Cigs.
Stratus also extended along the EEl River reach impacting local
airfield/landing strips. Early afternoon coastal clouds should
give way to mostly clear skies by mid-late afternoon. Similar
conditions expected again overnight as patchy low clouds return.
Gusty coastal winds will help maintain SKC at CEC today. VFR
conditions expected across the Inland mountainous/valley areas
(excluding Eel valley) through Friday. /TA
.MARINE...Northerly winds will continue to ramp up through the
evening hours, with occasional gusts to near gale force downwind
from the prominent capes and points. Winds will then decrease through
Saturday. Northerlies will once again increase on Sunday and
Sunday night, with gale force gusts likely in the outer waters.
These winds will then weaken toward the middle of next week as a
weak front approaches the area from the NW.
N short period wind waves will persist through the period. In addition,
a NW swell currently at a period of around 11 seconds will continue
into early next week with periods dropping to around 9 seconds. A
very small SW swell at around 16 seconds will develop this
weekend, with another small SW swell arriving by the middle of
next week. /SEC
.FIRE WEATHER...Red Flag Warnings remain in effect for zones adjacent
to our forecast areas to the south and east. Humidity this afternoon
through tonight will continue to be quite poor over the higher
terrain in the thermal belt, however winds will be mainly light.
Will continue to headline the very low RH recoveries in zones 277
and 276 in the FWF, with the worst conditions around Lake County.
Friday will be another hot and dry day, but a dry front will bring
somewhat cooler conditions with much improved overnight
recoveries from Friday night. However, next week will see a much
stronger ridge of high pressure build, with more dry and hot
weather expected. At this point in time, winds accompanying these
conditions look light.
NORTHWEST CALIFORNIA COASTAL WATERS...Small Craft Advisory until
3 AM PDT Friday for PZZ450.
Small Craft Advisory until 11 AM PDT Friday for PZZ470.
Small Craft Advisory until 9 PM PDT this evening for PZZ455.
Small Craft Advisory until 9 AM PDT Saturday for PZZ475.
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