Small Craft Advisory 32, NWS Medford, OR

Area Forecast Discussion
National Weather Service Medford OR
243 PM PDT Fri Mar 31 2017

.SHORT TERM...High pressure will keep mostly clear sky over our
forecast area tonight. The ridge will flatten on Saturday as a
short wave rides over. This will help to push a weak front inland.
Precipitation will be light and confined mainly at the coast (down
to around Gold Beach) and the Umpqua Basin, as well as showers
over the Cascades to around Hwy 140 crossing. High temperatures
south of the Umpqua Divide could be tricky as we may see mid and
high level clouds but confidence is moderate that we will at least
see mid 60s for the Medford area. Saturday night low temperatures
are expected to be mild from overcast sky.

The front will move east of the Cascades Saturday night and sky
will be clearing west of the Cascades. We will also see a thermal
trough developing and this will lead to gusty north to northeast
at the coast and the coastal range. Sky remains mostly cloudy to
the east, especially over the Warner Mtns. Clearing is expected
Sunday night for the west side and part of the Klamath Basin.
Overnight low temperatures Sunday night into Monday morning could
drop into the lower to mid 30s for the west side valleys, and
frost could be an issue.

Northwest flow aloft continues through Monday morning with cloudy
sky over the Cascades/Siskiyous and southern Lake over the Warner
Mtns into Modoc County. Upstream ridge is expected to shift inland
Monday afternoon. However, this ridging will be short-lived as
the front will spread clouds inland Monday night.

.LONG TERM (Tuesday through Friday)...The long-term starts with
an upper ridge axis overhead, signaling dry weather and near to
above normal conditions. Above normal temperatures would normally
be a lock with the strong ridge, but models suggest plenty of high
clouds in a dirty ridge scenario, which should limit the
afternoon warmth. The ridge axis shifts eastward on Wednesday, but
a warm air mass remains, and models do suggest some thinner high
clouds, so temperatures should reach above normal values. A
weakening front sputters into the forecast area on Thursday,
resulting in a cooling trend and a chance of rain for most of the
forecast area. A stronger front is expected to push into the
forecast area on Friday, bringing significant rain and wind to
most of the area. The operational GFS shows a strong atmospheric
river (AR) impinging on the coast Saturday morning, while the GEFS
mean shows a weaker AR at that time. The EC and GFS disagree on
timing, but the basic idea is that conditions will become wet by
Friday afternoon or evening, and these damp and cool conditions
will continue into Sunday.

&&

.AVIATION...31/18Z TAF CYCLE...Conditions are VFR most places and
will remain so today, with the last vestige of MVFR ceilings near
Roseburg about to clear. MVFR ceilings are expected to develop along
the coast north of Cape Blanco around 12Z early Saturday morning as
a weak front moves inland. MVFR conditions Saturday will be focused
mainly at the coast and in the Umpqua Basin as the front brushes the
northern portion of the forecast area. SK

&&

.MARINE...Updated 0830 AM PDT Friday 31 March 2017...With the
current strength of north winds at Pt. St. George buoy, the wind
forecast leans toward the stronger model solution. This has led to
sufficient confidence to issue a gale watch for the outer waters
south of Port Orford early Saturday evening through Sunday evening.
If there is support from the next model run or two, it may be
necessary to extend the gale watch a bit closer to shore...into the
outer portion of the inner waters around 5 to 8 NM from shore.
Also, much of the remainder of the waters is likely to see north
winds reach advisory strength.

Winds and seas will very briefly and slightly diminish early this
morning then high pressure offshore and low pressure on the coast
will bring increasing north winds into this evening with the
strongest winds south of Gold Beach. Winds will more noticeably but
briefly diminish again late tonight into Saturday morning as the
southern end of a weak front brushes through the waters north of
Cape Blanco. It may deliver a few light showers. A stronger episode
of north winds will develop Saturday afternoon and persist into
Monday. Besides the aforementioned likelihood of gales, very long
period swell moves in Saturday afternoon and combines with shorter
period west swell to bring hazardous bar crossings and possible
sneaker waves through Sunday morning. Seas will likely reach a peak
Sunday morning but improvement will be slow. Seas are likely to be
at a minimum as high pressure moves inland on Tuesday then the
pattern will change with a series of fronts likely during the second
half of the week. -DW

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...Beach Hazards Statement from Saturday afternoon through Sunday
     morning for ORZ021-022.

CA...None.

Pacific Coastal Waters...Small Craft Advisory until 2 AM PDT Saturday for PZZ356-376.
     Gale Watch from Saturday afternoon through late Sunday night for
     PZZ376.

FJB/NSK/NSK