Area Forecast Discussion
Issued by NWS Medford, OR

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FXUS66 KMFR 112152

Area Forecast Discussion
National Weather Service Medford OR
252 PM PDT Tue May 11 2021

.SHORT TERM...Warm and dry conditions will remain in place across
the area through Thursday with a strong upper level ridge in
place. A surface thermal trough will remain near the coast and
result in gusty north winds across the coastal waters and along
the coast. This will result in gusty north winds peaking in the
afternoon and early evening for areas at the coast.

A warming trend with high temperatures around 15 to 18 degrees
above normal is expected for inland areas Wednesday and Thursday.
Highs are forecast in the mid 80s to near 90 for inland valleys
west of the Cascades and in the lower to mid 80s for valleys east
of the Cascades. Gusty north to northwest winds are expected to
develop this afternoon and continue into early this evening for
areas from the Cascades west. On Wednesday and Thursday, models
indicate breezy to gusty northwest winds will affect much of the

At the coast, cooler and near normal temperatures are expected
except for locations across the southern Curry County coast were
offshore northeast winds will result in a Chetco warming effect.
High temperatures today have warmed into the the upper 70s to low
80s near Brookings. Highs in the mid to upper 70s are expected
again Wednesday afternoon. Otherwise, along the coast, expect
sunny conditions during the day with areas of nighttime and early
morning low clouds or fog, mainly along the coast north of Cape
Blanco and in the Coquille Valley.

.LONG TERM...Friday through Tuesday...Heading into the extended
period southerly winds begin to feed moisture from the south into
northern California late morning Thursday. This then brings us into
the extended period. An upper level trough deepens along the west
coast, and begins to close just offshore of the forecast area by
Friday afternoon. Models are in remarkably good agreement in closing
this upper low, both in location and depth, Friday evening. All
operational models are also in very good agreement in indicating an
area of instability extending from the Mt Shasta area and to the
east and northeast from there. With this agreement have consolidated
and extended the area of possible thunderstorms, but although both
the ECMWF and the GFS are indicating moderate QPF in this area, as
well as computed from 850 MB LI`s near -2, the biggest factor
leading into this event will be the amount of moisture feeding in
ahead of it. With this uncertainty have kept the chances of
thunderstorms to slight chance being still three days out. By
Saturday morning models remain in remarkably good agreement in
deepening this upper low and moving it down to the Bay area of
central California with almost the exact location and depth.

The closed low then migrates to southern Nevada with an upper ridge
nudging into the region by Sunday morning. A thermal trough deepens
along the coast with this pattern, bring temperatures back up to
well above normal on Sunday. Models diverge greatly then heading
into next week, with ensembles showing great dispersion and have
gone with a more probabilistic solution of an unsettled pattern into
next week. Sven


.AVIATION...For the 11/18Z TAF Cycle...
VFR conditions are generally expected through the TAF period as the
forecast area experiences a general north to northeasterly wind flow
under high pressure. Northerly winds will be moderate to strong and
gusty along and near the coast and across the coastal waters, with
some gales over the coastal waters south of Cape Blanco. Inland
areas will be breezy, but winds will generally be stronger west of
the Cascades versus east of the Cascades. A period of IFR/LIFR
ceilings and visibilities are possible again in the Coquille Basin
to KOTH and along and near the lower Umpqua River early Wednesday
morning, mainly between 12 and 16Z. Schaaf/~BTL


.MARINE...Updated 250 PM PDT Tuesday, 11 May 2021...
The thermal trough will continue to produce gusty north winds and
steep to very steep seas through this next weekend, with the
strongest winds and steepest seas occuring south of Cape Blanco and
during the afternoon and evening hours. North gales are expected
again this afternoon and evening. North winds are likely to be a bit
less strong Wednesday and Thursday, but seas are expected to remain
steep to very steep. Higher winds and seas, to include gales south
of Cape Blanco, are expected to return Friday afternoon and evening.



Pacific Coastal Waters...Small Craft Advisory until midnight PDT Friday night for
     Hazardous Seas Watch from late tonight through Friday evening
     for PZZ356-376.
     Gale Warning until 5 AM PDT Wednesday for PZZ356-376.


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