Area Forecast Discussion
Issued by NWS Medford, OR

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000
FXUS66 KMFR 272154
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
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


&&

.Aviation...For the 27/18Z TAF cycle...Areas of VFR cigs north of
the umpqua divide continue to slowly dissipate this morning. The
lower conditions will return to the same areas again tonight...but
will likely not be as widespread. The remainder of the area will
remain VFR through Friday night...except for patchy fog in the
Klamath Basin around sunrise. Sven

&&

.Marine...Updated 1030 AM PDT Fri 27 May 2016...Offshore high
pressure and a thermal trough near the coast is bringing strong
north winds and very steep wind wave dominated seas to the
area...especially south of Cape Blanco. This pattern will remain in
place through the middle of next week...but the trough will weaken
through Sunday...then redevelop next week. The winds and seas will
abate as the trough weakens...then may increase again next week.

It should be noted that the sea state through the weekend will be a
chaotic mix of wind wave and very fresh swell. Thus, while seas are
fairly steep 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 Friday evening. Numerical models do
generally indicate winds and seas will ramp upward again from the
north Sunday and Monday in the southern coastal waters area beyond 5
nautical miles of the coast. 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.

$$

NSK/SBN/SBN



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