Area Forecast Discussion
Issued by NWS Medford, OR

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000
FXUS66 KMFR 280316
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
816 PM PDT FRI MAY 27 2016

.DISCUSSION...No updates planned this evening. Continued fairly
benign northwest flow aloft will result in a quiet evening
becoming a quiet night across the forecast area. High pressure
offshore will keep northerly to offshore flow going over the area,
and this will limit or prevent any stratus formation overnight. If
any stratus does form, it will be over the northern Umpqua basin
north of Sutherlin. Elsewhere, it will be mostly clear tonight,
and likely chilly, especially in the upper Klamath Basin where a
freeze warning remains in place. -Wright

&&

.PREV DISCUSSION... /Issued 457 PM PDT FRI MAY 27 2016/

DISCUSSION...The aviation and marine sections have been updated.

AVIATION...For the 28/00Z TAF cycle...VFR conditions with clear
to partly cloudy skies are expected through Saturday afternoon...
except for local early morning MVFR stratus between around 11Z and
16Z in the Umpqua Valley. This stratus is most likely to form
in the southern portion of the valley near Canyonville. -DW

MARINE...Updated 330 PM PDT Fri 27 May 2016...Offshore high
pressure and a thermal trough near the coast will continue to bring
moderate to strong north winds and steep wind dominated seas to the
waters through the middle of next week.

It should be noted that the sea state will be a chaotic mix of wind
wave and very fresh swell. Thus, while seas are fairly steep and
choppy in all areas, they are only 3-6 feet north of Cape Blanco. On
Saturday winds will diminish and the strongest winds and highest
seas will shift a bit more west of the coast. Additionally,
conditions are expected to fall below warning levels to advisories
south of Cape Blanco for Saturday and Sunday with no advisories
expected north of the Cape after this evening. Numerical models do
generally indicate winds and seas will ramp upward again from the
north Sunday into Monday with the strongest winds and highest seas in
the southern coastal waters area beyond 5 nautical miles of the
coast. Seas will be at a minimum on Saturday morning and at a
maximum on Monday evening. -DW

PREV DISCUSSION... /Issued 254 PM PDT FRI MAY 27 2016/

Short term...Temperatures are once again similar to the previous
day...with this being the last day of relatively constant weather
conditions. Afternoon high temperatures will once again be below
normal...and this makes 8 out of the past 9 days at or below
normal in terms of temperatures. Onshore flow is similar to
yesterday in terms of pressure gradients so expect some clouds to
make their way into the Umpqua Basin tonight, but coverage should
not be as much as yesterday. East of the Cascades, significantly
lower dew points are being observed today compared to yesterday,
and with mostly clear skies again tonight, freezing conditions are
likely in portions of the Klamath Basin. A freeze warning has been
issued for that area at NPWMFR.

Tomorrow marks the first significant warming of the air mass in more
than a week as 850mb temperatures increase by at least 5C.
Temperatures will be a few degrees above normal in most places, and
this trend will continue on Sunday but with only a slight warmup
because weak upper troughing will keep the ridge at bay for one more
day. This upper troughing has a slight potential of bringing some
drizzle to the coast and Umpqua Basin but have left it 10 percent
or less at this time. The next run of high resolution models may
have some more insight that could force a nudge upwards of POPs
Sunday morning.

The upper ridge axis moves overhead nearly overhead on Monday,
resulting in upper-80 degree temperatures west of the Cascades and
near-80 degree readings east of the Cascades. Additionally, moderate
offshore northeasterly winds will heat things up in Brookings,
making 80 degree temperatures within reach.

Long term...Tuesday through Friday. Models are in tight
agreement with all of the ensemble plots in line with an upper level
ridge over the west coast. Offshore flow is all the way across the
east side with a deep thermal trough on the coast Tuesday morning
with west side temps near 90 to the mid 90s. The thermal trough
moves inland Wednesday and the warmest day of the stretch will be on
Wednesday inland. Southerly flow begins to feed moisture into the
region Thursday with the GFS and ECMWF indicating LI`s in the -2
range. However, the 700-500 mb RH is less than 50 percent and cells
that will develop will fizz out at the top as the flow hits the dry
layer in the cells. The ECMWF has an upper low swinging up on Friday
with instablity and moisture indicating possible thunderstorms, but
this is an outlying solution and have gone only slight chance showers
due to uncertainty at this time. Sven

&&

.MFR Watches/Warnings/Advisories...
OR...Freeze Warning from 2 AM to 8 AM PDT Saturday for ORZ029.

CA...Freeze Warning from 2 AM to 8 AM PDT Saturday for CAZ084.

Pacific Coastal Waters...Small Craft Advisory for hazardous seas until
     11 PM PDT this evening for PZZ350-356-370-376.
     Small Craft Advisory until 11 PM PDT Monday for PZZ356-376.
     Hazardous Seas Warning until 11 PM PDT this evening for
     PZZ356-376.

$$



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