Area Forecast Discussion
Issued by NWS Eureka, CA
FXUS66 KEKA 241159
AREA FORECAST DISCUSSION
National Weather Service Eureka CA
459 AM PDT WED AUG 24 2016
.SYNOPSIS...Coastal areas can expect overnight and morning
cloudiness the next few days with some clearing in the afternoons.
Temperatures will continue to be near to slightly above normal
across the interior through Thursday. An upper trough will slide
over the Pacific Northwest late in the week bringing more seasonal
temperatures. Little, if any, rain is expected.
.DISCUSSION...Coastal low clouds and fog spread inland early
Tuesday evening along the Redwood Coast. The clouds and fog have
continued to slowly expand over the coastal waters. Clouds should
erode from the inland side fairly quickly later this morning. As a
low pressure trough sets up shop over the area later in the week,
the marine layer should deepen a bit. Additionally, temperatures
will return to near normal by the weekend. The models continue the
trend of cutting off an upper low farther offshore by late this
week. This low may not move back toward the area until the middle
of next week. As a result, have kept a generally dry forecast. See
the fire weather section below for more info. /SEC
.AVIATION...VSBYs have been fluctuating around 1/2SM to 1/4SM
in fog (FG) at KACV and KCEC through the night. VSBYs will improve
around mid to late morning as the land mass heats up. A shallow
layer of fog and LIFR ceilings will probably meander near the
shoreline through afternoon. Complete dissipation is not certain.
Overall expect better flying conditions by the afternoon hours as
the eastern portions of the air terminals clear out of the fog. The
western halves may continue to be pestered with low vsbys from the
fog (FG) over the ocean. Shallow marine layer conditions with low
vsbys and LIFR ceilings will probably return again this evening.
Slightly stronger easterly flow through the night may inhibit
redevelopment overnight especially at KCEC where the easterly flow
above the fog layer looks to be the strongest. GFS guidance has
winds switching around to the south and suspect foggy conditions or
partially foggy conditions at KACV and KCEC will most likely still
be around through early morning hours on Thu. On Thu, the stronger
easterly flow pattern should result in eradication of the stratus.
north of the Cape. Southerly winds Thu night will probably advect
fog and stratus back into the terminals by Fri.
Stratus from Sonoma county will make a run toward KUKI early this
morning. Southerly winds were weaker compared to the last night and
RH`s were down by 9%. IFR ceilings will probably push into Hopland
by daybreak, but confidence is by no means high there will even be a
few or scattered low clouds at KUKI by daybreak. Otherwise VFR
conditions are expected to continue at KUKI through the period.
.MARINE...High pressure offshore will maintain light to moderate
northerlies over the waters today and tonight. Scatterometer pass
from Tuesday evening indicated winds around 15-20 KT in PZZ470 and
PZZ475. GFS and NAM continue to indicate northerly winds sustaining
around this level today through tonight in the offshore waters, then
dropping off through the day on Thu. Even though wind speeds are
forecast to remain under our criteria for an ADVISORY, steep seas
around 6 to 8 ft are expected for the offshore waters through
Northerly winds will drop off across the offshore waters on Thu and
become southerly by Friday as a weak surface low spins up. The
southerly winds are most likely underdone and have increased speeds
above the model guidance, especially near Cape Mendo. Broad weak low
pressure over the waters will likely maintain light winds fields and
low seas through the weekend.
.FIRE WEATHER...Offshore winds are expected to increase along the
ridgetops of interior Del Norte and NE Humboldt counties late
tonight and early Thursday. Gusts to 30 mph are likely on exposed
ridgetops for several hours. In addition, relative humidity
recoveries will be poor at higher elevations. Will continue to
highlight this in fire weather zones 203 and 204. /SEC
NORTHWEST CALIFORNIA COASTAL WATERS...
Small Craft Advisory until 5 PM Thursday for PZZ470.
Small Craft Advisory until 9 AM Thursday for PZZ475.
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