Area Forecast Discussion
Issued by NWS Eureka, CA

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000
FXUS66 KEKA 241203
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
503 AM PDT Sun Jun 24 2018

.SYNOPSIS...Warm and dry conditions will continue for much of the
next week across the interior, although the hottest day will be
today. Coastal clouds will increase later today and tonight, and
will continue to be found during at least the morning hours much
of this week.

&&

.DISCUSSION...With a strong thermal trough along the coast this
morning and an upper-level ridge overhead, warm and dry offshore
flow is keeping skies clear across most of Northwest California.
The exception is along the southern Mendocino coast, where stratus
is trying to creep northward past Point Arena. Southerly winds
will likely bring these clouds up past Fort Bragg later this
morning, while the rest of the coast will stay clear until later
this afternoon. Winds are generally light or calm across our
region this morning, but are tending easterly across the
mountainous terrain, where the offshore winds are keeping
temperatures in the 60s and 70s and resulting in low relative
humidity values. As an upper-level trough approaches this evening,
a surge of marine air will push inland, and even by this afternoon
winds will begin to shift onshore. That said, afternoon breezes
will be lighter than the past few days. Stratus will subsequently
return to entire coast late this afternoon or by this evening, and
persist well into Monday, especially between Trinidad and
Fortuna. This marine air and cooling aloft under the passing
upper-level trough will help bring temperatures down into the
upper 80s and low 90s on Monday across the interior...where
temperatures will still range from the mid 90s to around 100 this
afternoon. These levels will still carry a low risk of heat-
related illness for sensitive groups today, but will not reach
criteria for a heat advisory, as these temperatures are fairly
common for late June.

The upcoming week will be fairly straight-forward with no
precipitation expected across northwest California right through
next weekend. Upper-level ridging will build back a bit on Tuesday
in the wake of this first trough, which will allow interior high
temperatures to rise back a bit into the 90s. Coastal low clouds
will also likely be suppressed a bit, but mornings around the
Humboldt coast will be cloudy. Additional upper-troughs will push
across the Pacific Northwest mid to late week, which may tend to
drop inland high temperatures a bit further into the 70s and 80s.
There is model disagreement regarding the track and depth of these
systems, which will determine how warm the late week and next
weekend period ends up. Meanwhile along the coast, temperatures
will remain rather seasonable, with morning cloudiness more likely
for the Humboldt and southern Mendocino coast, but afternoon
sunshine a good bet there as well. /AAD

&&

.AVIATION...Easterly winds aloft and drying at the surface have
prevented widespread stratus from reforming this morning as was
expected. There is still a low potential for ground fog to form
around Humboldt Bay this morning which may temporarily reduce
conditions at ACV however this probability is low. Winds aloft will
become more westerly this afternoon and early evening which means
low clouds and reduced visibilities will return to the coast.
Conditions should rapidly deterioate to IFR and maybe even LIFR at
ACV and CEC by late this afternoon as the stratus makes a quick
return back to the coast and remain reduced through tomorrow
morning. /WCI

&&

.MARINE...Pressure gradient will continue to relax today allowing
wind gusts to fall below gale force by this morning. This is only a
respite from gale force gusts though as they will return again by
Monday afternoon. These persistent north winds will generate very
steep seas through the rest of the weekend and into next week. A
small craft advisory will replace the current gale across the outer
waters later this morning, with additional gale warnings possible
early next week. /WCI

&&

.FIRE WEATHER...Will continue to headline hot and dry conditions
in our Lake county, eastern Mendocino, and Trinity zones through
today, as offshore flow will continue to result in hot
temperatures and low RH. Over the high terrain, RH recoveries have
been particularly poor, only in the 20s in many cases above 3000
feet. Fortunately winds are fairly light. A gradual moderating
trend can then be expected Monday and beyond, with slightly
improved afternoon temperatures and overnight recoveries. Still,
afternoon temperatures across interior areas will likely remain
near to slightly above normal for much of the next week. A
deepening marine layer tonight through at least Tuesday will
bring cool and damp marine layer air farther inland as well.
Breezy north winds along coastal ridges will weaken slightly
Sunday and Monday, but will increase again Tuesday and will be
gusty in exposed locations during the afternoon hours through the
rest of the week.

&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...None.
NORTHWEST CALIFORNIA COASTAL WATERS...Small Craft Advisory until
     3 AM PDT Tuesday for PZZ450-455.

     Gale Warning until 9 AM PDT this morning for PZZ470-475.

&&

$$

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