Area Forecast Discussion
Issued by NWS Eureka, CA

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FXUS66 KEKA 201112
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
412 AM PDT Fri Oct 20 2017

.SYNOPSIS...Rain and snow showers will continue throughout the day
as a broad trough exits the region. Behind the trough, high
pressure will gradually build over the Pacific Northwest; however,
drier and warmer weather will be put on hold until early next week
due to a weak disturbance skirting to our north. This will bring another
round of precipitation to the area on Saturday into Sunday.


&&

.DISCUSSION...Wet weather will continue into the weekend as a
broad trough exits the region today. This means we can expect to
see rain showers throughout the day today, especially for those
north of Mendocino County. Additionally, snow levels are forecast
to hold around 4500 feet so accumulating snow is expected for the
Trinity Alps. Once the trough exits the region, high pressure will
gradually build overhead. Warmer and drier conditions are expected
by early next; however, a weak disturbance will pass to our north.
This will bring one last round of accumulating rain to northwest
California and will primarily affect Del Norte and northern
Humboldt counties. Cooler temperatures are also forecast during
this time frame, with the coldest temperatures occurring inland.
Trinity County has already experienced a hard freeze, so no
headlines are needed for the zone. Northeast Mendocino County is
projected to see low temperatures in the mid to upper 30s, but
confidence is not very high that frost will actually occur. For
those who have sensitive plants, you may want to cover them up or
move them inside if possible.

As noted earlier in the discussion, warmer and drier conditions
are expected to return to the area. Models continue to show
anomalously warm 850 temps along with temperatures in the upper
80s to low 90s near Ukiah. We`ll keep an eye on the affects of
pattern change but overall confidence is high for warm and dry
conditions to return next week. /KR/KML



&&

.AVIATION...Occasional shower activity will continue through
the morning hours as cold trough aloft transitions eastward across
the area. VFR conditions will be the general rule, however a few of
the heavier showers may produce brief MVFR ceilings and reduced
vsbys early this morning.

&&

.MARINE...High surf will continue to pound the shoreline of NW
California today. An incoming W-NW swell around 20 feet with periods
near 17 seconds will likely result in breakers of 23 to 25 feet in
the surf zone and pose a significant hazard for mariners traversing
harbor entrances. The swell should subside late today and tonight,
however above normal surf will likely persist into at least the
evening hours. The swell will slowly subside over the weekend,
however seas will remain high enough to warrant an advisory for
seas. A warm front will generate a new round of brisk southerly
winds and steep southerly waves north of Cape Mendo on Saturday.
Winds will fall below advisory or warning levels on Sunday, however
WNW swell will likely remain elevated, around 10 feet or higher.
Brisk northerly winds and short period northerly wind waves will
return early next week. Another long period (but smaller) WNW swell
will start to build to formidable levels on Monday. The beach hazard
threat will once again be on the rise as the swell commingles with
the shorter period northerly waves.


&&

.FIRE WEATHER...Cool and rainy conditions will persist over the
weekend which will squash any critical fire weather conditions
for the next few days. The concern on the horizon will be
building high pressure bringing anomalously warm low level
temperatures early next week. As previously mentioned, this means
inland temperatures could potentially be 10 to 15 degrees above
normal values with plummeting afternoon humidity across eastern
Trinity and eastern Mendocino counties. Fortunately the rain
should help hinder fire threats but we will need to analyze how
the fuels respond to the cool and moist conditions over the next
few days. /KML/KR


&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...High Surf Advisory until 6 PM PDT this evening for CAZ101-103-
     104-109.

NORTHWEST CALIFORNIA COASTAL WATERS...Hazardous Seas Warning until 6 PM PDT this evening for PZZ450-
     455-470-475.

&&

$$

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