Hazardous Seas Warning 55, NWS Medford, OR

Area Forecast Discussion
National Weather Service Medford OR
100 AM PDT FRI JUL 29 2016

.DISCUSSION...29/00Z NAM/GFS/EC IN.

The main forecast challenge for Friday and Saturday will be the
potential for thunderstorms. The models show a short wave rotating
into Northern California Friday afternoon. This combined with
intense surface heating will promote strong upward motion. The
models lifted indices support this scenario. The limiting factor
will be low level moisture...model soundings indicate that it will
remain very dry in the lower levels. Therefore...any thunderstorms
that do develop will be high-based...like 10K MSL...with little
or no precipitation reaching the ground. They may create some
gusty winds though. Coverage will be no more than isolated and
will mostly be over Northern California. The southern Cascades in
Oregon may see some activity late this afternoon and evening.

It will be another very hot day with inland highs 10 to 15 degrees
above normal. The Medford area and the Klamath and Shasta valleys
in Northern California will likely break 100 degrees again.

On Saturday there will be less upper level support for convection...
but what support there is will stretch from the Mount Shasta area
northeast into Modoc...southern Klamath...and southern Lake
County. Low levels will be drier than Friday...so thunderstorms
will once again be high-based...nearly dry...and may create some
gusty winds. Coverage will be isolated. However...temperatures
will be cooler as ridging aloft weakens over the area. Inland high
temperatures will be near normal over the Umpqua Basin...5 to 10
degrees above normal over the rest of southern Oregon...and around
8 to 12 degrees above normal over Northern California.

The last of the thunderstorms will dissipate Saturday
evening...and that will likely be it for thunderstorms through
the coming week. Then the main item of concern will be wind.

The winds will be generated by two troughs moving onshore to the
north of the area. The first one will be relatively weak and will
move onshore Saturday night into Sunday. This will bring some
gusty winds to the east side Sunday. Sunday highs will be cooler
...about 5 to 10 degrees above normal.

The second trough will move onshore Monday night and this one will
be much stronger. It will push a dry front onshore...and winds
will be strong and gusty east of the Cascades Monday afternoon and
evening. This...combined with the very dry air already in place
may make for Red Flag Warning conditions over the area.

Temperatures will cool Monday into Tuesday. By Tuesday inland
highs will be near normal over Southern Oregon and 0 to 5 degrees
above normal over Northern California.

Inland temperatures will warm a bit Wednesday through Friday as
ridging once again strengthens over the area...but temperatures
will not be nearly as hot as they will be today. It will remain
dry with light to moderate southwest flow aloft.

&&

.AVIATION...29/06Z TAF cycle...VFR conditions will continue through
Friday morning at inland locations. IFR to LIFR marine stratus in
the Coquille Valley will persist until around 16-18Z Friday morning
before dissipating. Moderate to strong and gusty north winds are
expected for most areas along the coast and offshore, though with a
decrease during the early morning hours. Cumulus buildups are
expected over the higher terrain of northern California into south
central Oregon on Friday afternoon and evening with a slight chance
of thunderstorms. -Sven

&&

.MARINE...Updated 930 PM PDT Thursday, 28 July 2016...A thermal
trough along the coast and high pressure offshore will continue to
produce moderate to strong north winds and steep to very steep
seas through the weekend and into next week. Conditions will be
most hazardous north of Cape Blanco through Friday evening. South
of Cape Blanco the most hazardous conditions are expected to be
through Saturday evening. Northerly winds will be nearly as strong
Sunday into Sunday evening. Winds may drop below gale force across
the waters on Monday but winds are likely to strengthen again on
Tuesday then remain moderate to strong through the middle of the
week. -Sven

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...None.

CA...None.

Pacific Coastal Waters...Small Craft Advisory until 11 PM PDT Sunday for
        PZZ350-356-370-376.
     Hazardous Seas Warning until 11 PM PDT Sunday for PZZ356-376.
     Hazardous Seas Warning until 11 PM PDT Friday for PZZ370.
     Gale Warning until 11 PM PDT Sunday for PZZ376.

15/15/06