Small Craft Advisory 110, NWS Eureka, CA

137 
WHUS76 KEKA 302226
MWWEKA

URGENT - MARINE WEATHER MESSAGE
NATIONAL WEATHER SERVICE EUREKA CA
326 PM PDT MON OCT 30 2017

PZZ470-310630-
/O.CON.KEKA.SC.Y.0110.000000T0000Z-171031T1100Z/
PT ST GEORGE TO CAPE MENDOCINO 10 TO 60 NM-
326 PM PDT MON OCT 30 2017

...SMALL CRAFT ADVISORY REMAINS IN EFFECT UNTIL 4 AM PDT
TUESDAY...

* WINDS...NORTHERLY GUSTS UP TO 30 KT TONIGHT.

* WAVES/SEAS...NORTHERLY 7 TO 9 FT AT 6 TO 8 SECONDS TONIGHT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A SMALL CRAFT ADVISORY MEANS THAT WIND SPEEDS OF 21 TO 33 KNOTS
ARE EXPECTED TO PRODUCE HAZARDOUS WAVE CONDITIONS TO SMALL CRAFT.
INEXPERIENCED MARINERS, ESPECIALLY THOSE OPERATING SMALLER
VESSELS SHOULD AVOID NAVIGATING IN THESE CONDITIONS.

&&

$$

574 
WHUS76 KEKA 310411
MWWEKA

URGENT - MARINE WEATHER MESSAGE
NATIONAL WEATHER SERVICE EUREKA CA
911 PM PDT MON OCT 30 2017

PZZ470-311100-
/O.CON.KEKA.SC.Y.0110.000000T0000Z-171031T1100Z/
PT ST GEORGE TO CAPE MENDOCINO 10 TO 60 NM-
911 PM PDT MON OCT 30 2017

...SMALL CRAFT ADVISORY REMAINS IN EFFECT UNTIL 4 AM TUESDAY...

* WINDS...NORTHERLY GUSTS UP TO 30 KT TONIGHT.

* WAVES...N 6 TO 9 FT AT 8 SECONDS TONIGHT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A SMALL CRAFT ADVISORY MEANS THAT WIND SPEEDS OF 21 TO 33 KNOTS
ARE EXPECTED TO PRODUCE HAZARDOUS WAVE CONDITIONS TO SMALL CRAFT.
INEXPERIENCED MARINERS, ESPECIALLY THOSE OPERATING SMALLER
VESSELS SHOULD AVOID NAVIGATING IN THESE CONDITIONS.

$$

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
152 PM PDT Mon Oct 30 2017

.SYNOPSIS...Dry mild conditions are likely across much of
northwest California during Tuesday morning and afternoon.
Thereafter, a cloudy marine layer is forecast to surge northward
along the coast Tuesday night into Wednesday, followed by
increasing cloud cover aloft as a storm system approaches from the
north. Rain and cooler temperatures are likely Thursday afternoon
through the weekend.

&&

.DISCUSSION...Modest cold air advection is spreading southward
above the surface across coastal portions of northwest California
Monday afternoon. This is resulting in weak destabilization that
is aiding in rapid clearing of marine stratus across much of the
area (the one exception being a very localized area of persistent
clouds near Ferndale). Moderate offshore winds are forecast to
develop tonight into Tuesday from 925 mb upwards, which will yield
warming aloft that will re-stabilize/cap the marine boundary
layer. The offshore winds will also yield a drying
airmass...particularly at ridgetop level, which will favor Tuesday
morning-early afternoon sunshine and mild temperatures. As the
afternoon progresses, hi-res model guidance shows a trough of
surface low pressure advancing WWD away from land, with low-level
southerlies developing to its immediate east along the coast.
This will aid in a northward surging marine layer that will likely
lead to the redevelopment of stratus for coastal areas late
Tuesday afternoon into Tuesday night.

Meanwhile, model guidance shows large-scale height falls
increasing in strength mid week into Friday over the NERN Pacific
and PAC NW region. A fairly large upper-level trough will evolve
over the area as a result, with ascent and moistening taking place
downstream over NWRN CA. Rain will subsequently begin to develop
during Thursday, and then maximize in intensity during Friday as a
shortwave trough moves toward the region. In addition, significantly
colder air aloft is forecast to spread across the area by
Saturday, which will cause snow levels to fall to 3000-4000 feet.
Thus, several inches of snow will be possible over the higher
mountainous terrain. By Sunday/Monday, forecast uncertainty
increases greatly due to model differences in shortwave
evolution...however, the current model trend is for lower
precipitation chances early next week.

&&

.AVIATION...Deepened marine clouds persisted along the Redwood
Coast through much of the morning...CIGs hovering in VFR-MVFR
(~025-045 FT) and VIS occasional and briefly dropping into IFR.
The deeper marine layer could be attributed to a batch of lower
level cold air advecting over the coastal waters thus causing some
destabilizing... then resulting in the higher (stratocumulus
like) cloud bases. Shortly before and after noonday, VIS Sat Pic
showed a north-south push clearing out much of the coastal
airports. However, into early afternoon, low MVFR cigs continued
to hover of the EEL River Delta and Humboldt/Arcata Bays. Model
guidance is indication uncertainty if ACV & CEC will redevelop the
amount marine cloudiness in the next 24 hours as today was.
However, do expect "some" of the clouds trapped in the EEl Delta
to move back over Humboldt Bay. Expect MVFR- IFR conditions
(mainly VIS) will mostly have some minor impact at some coastal
airfields. Interior areas: higher clouds moved across interior
Mendocino. Most noticeably though was that some inland river
valleys developed local fog conditions with pockets of marine
clouds able to push across the local higher terrain. This was due
to the deeper marine layer of course. Expect some patchy morning
fog over a few local valleys...otherwise VFR inland. /TA

&&

.MARINE...Northerly winds have been increasing near the Oregon
border behind a dry cold front today. Northerly winds and seas are
forecast to be borderline (areal coverage wise) for an advisory
tonight. Seas look sufficiently steep with about 50% coverage
(based on NWPS) for an advisory across PZZ470. Otherwise, light to
moderate southerlies will start to unfold on Tue and continue
into Wed and Thu as a broad and diffuse surface low develops over
the waters. Seas for the most part will remain relatively quite
through the week with a combination of long period NW swells and
shorter period wind waves. The most significant wave energy
(steepness wise) will start to develop on Friday and perhaps last
into Sat. A cold storm system will drop southward from the Gulf of
Alaska on Friday, generating short to mid period NW swell that is
forecast to reach 10 ft or so. An advisory for small vessels is
highly probable.

&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...None.
NORTHWEST CALIFORNIA COASTAL WATERS...Small Craft Advisory until
     4 AM PDT Tuesday for PZZ470.

&&

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see the forecast zone map online:
http://www.weather.gov/eureka/zonemap.png

Hazardous Weather Outlook
National Weather Service Eureka CA
322 AM PDT Mon Oct 30 2017

CAZ101-103-104-109-112-113-311030-
Coastal Del Norte-Northern Humboldt Coast-Southwestern Humboldt-
Mendocino Coast-Southwestern Mendocino Interior-
Southeastern Mendocino Interior-
322 AM PDT Mon Oct 30 2017

This hazardous weather outlook is for northwest California.

.DAY ONE...Today and tonight.

No hazardous weather is expected at this time.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...
Spotter activation is not expected at this time.

CAZ102-105>108-110-111-311030-
Del Norte Interior-Northern Humboldt Interior-
Southern Humboldt Interior-Northern Trinity-Southern Trinity-
Northwestern Mendocino Interior-Northeastern Mendocino Interior-
322 AM PDT Mon Oct 30 2017

This hazardous weather outlook is for northwest California.

.DAY ONE...Today and tonight.

No hazardous weather is expected at this time.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday.

Mountain snow is expected late in the week and over the weekend. Snow
will likely only impact the tallest peaks initially, but snow levels
will fall to around 3000 to 4000 feet over the weekend.

.SPOTTER INFORMATION STATEMENT...
Spotter activation is not expected at this time.