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fxus66 keka 201144 

Area forecast discussion
National Weather Service Eureka California
444 am PDT sun Oct 20 2019

Synopsis...another round of showers will move through the area
today, mainly north of Cape Mendocino. Only minimal rainfall is
expected. Otherwise, a sharp warming and drying trend can be
expected Monday through the end of the week, with gusty Ridgetop
winds and elevated fire weather possible Wednesday and Thursday.


Discussion...the combination of a surface warm front and one more
weak disturbance embedded in the northwest flow aloft will bring a
final round of showers to the area today before a warm and dry
pattern takes hold for the coming week. The bulk of the shower
activity will once again be focused north of Cape Mendocino, with
more spotty coverage across Mendocino County. Rainfall amounts will
be much lighter than in recent days, likely topping out around a
tenth of an inch in most areas with locally higher amounts over
favorable terrain. Showers will quickly taper off during the evening
as high pressure starts to build into the region, ushering in warmer
and drier conditions for Monday. /Cb


Long term...a sharp warming and drying trend will begin Monday
as high pressure builds across the eastern Pacific, and this will
continue through the end of the week. Well above normal
temperatures can be expected area-wide from Monday through
Saturday, particularly in Mendocino County where high temperatures
are expected to remain consistently in the mid to upper 80s
throughout this period, and may even approach 90. While these
kinds of temperatures will likely fall short of all time records,
it would be a significant departure from normal. On Wednesday and
Thursday, northeasterly winds are expected to increase throughout
the region, particularly across higher elevations. These gusty
winds, when combined with the expected very low humidity, may
result in at least locally elevated to potentially critical fire
weather conditions. For more details regarding this potential,
please see the fire weather discussion section below. /Brc


Aviation...VFR ceilings will gradually lower this morning as a warm
front approaches the Redwood coast, with areas from acv to cec
seeing some spotty light rain pushing in. MVFR to even IFR ceilings
may develop by midday or this afternoon, especially along the del
norte coast. Southerly winds will increase a bit along the coastal
headlands between Cape Mendocino and Pt St George, with some gusts
to 20 kt possible, but otherwise winds will remain light across most
of northwest California. Visibility with the light rain should be in the 3
to 6 sm range at worst, and should taper off early this evening.
This evening low ceilings may scatter, but there is the potential
for some redevelopment of low ceilings at cec and acv overnight.
Interior areas of Trinity and Mendocino County will likely only see
some scattered clouds today with clearing skies tonight, but would
not rule out some patchy fog. /Aad


Marine...a warm front will bring occasional light rain and 10 to 20
kt southerly winds to the coastal waters today, mainly to areas
north of Cape Mendocino. Some increase in short-period seas will
occur as a result, but otherwise the overall sea state will be
mainly comprised of a substantial mid-period swell of around 10 to
11 feet at 13 seconds. This swell will drop below 10 feet at some
point later today or tonight, but opted to extend small craft
advisories until this afternoon.

High pressure will begin to build in from offshore on Monday,
resulting in northerly winds returning, with small craft conditions
developing south of Cape Mendocino. As a thermal trough develops
along the California coast by midweek, the pressure gradient will
increase. Stronger northerly winds will then expand, possibly
bringing gale force gusts to portions of our coastal waters around
Wednesday. Steep seas will build as well, possibly reaching 10 ft
across the outer waters. /Aad


Fire weather...recent wetting rains over the past few days have
brought much needed moisture to fuels across a large portion of
the area, in particular across Humboldt and del norte counties.
Rain totals have been a bit more meager across most of Trinity
County, and even lower across Mendocino County where some areas
have only seen close to .10 inches of new rainfall in the past
three days. This will likely be important moving forward, as a
prolonged warming and drying trend is expected to begin Monday and
continue through the end of the week, in addition to potentially
significant offshore winds Wednesday and Thursday.

While fuels across the wetter areas of del norte, Humboldt and
western/northern Trinity counties are not likely to dry
sufficiently to support rapid wildfire growth over the next week,
this is much less certain across Mendocino, lake and southern
Trinity counties where much less rain has fallen. As a result,
there is the potential for at least elevated to potentially
critical fire weather conditions to develop in some areas
Wednesday and Thursday, with the highest likelihood of occurrence
across southern Mendocino and lake counties. /Brc


Eka watches/warnings/advisories...
Northwest California coastal waters...Small Craft Advisory until
3 PM PDT this afternoon for pzz450-455-470-475.



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