000
FXUS66 KMFR 220037
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
535 PM PDT Wed Aug 21 2019

.Updated aviation discussion.

.DISCUSSION...21/12Z NAM/GFS/EC in.

As far as precipitation goes, all the action will be today and
this evening. A long wave upper trough just offshore is pushing a
weak front onshore at this time. The associated precipitation has
been light, and the bulk of it is falling along the coast and in
the Coast Range. Most of the rest is falling over the Umpqua Basin
and adjacent Cascades. Other inland locations from the Cascades
west may get a few hundredths, but that`s will be about it. The
front will dissipate as it moves onshore, and the main effects
over most of the area will be a short-lived cooldown west of the
Cascades today and gusty winds east of the Cascades. Inland
temperatures will be 5-10 degrees below normal west of the
Cascades, but around 5 degrees above normal to the east.

The upper level trough supporting this front will move through the
CWA this later this afternoon and evening, and any lingering
precipitation will end this evening. However, a marine push will
likely bring cloud cover to the coast and Umpqua Basin overnight.

An upper level ridge will then build in from the southwest, and a
thermal trough will develop near the coast. This will bring in a
more typical hot and dry summer pattern over the next few days.
Temperatures will warm a bit Thursday, a lot Friday, then Saturday
highs will be about the same as the Friday highs. In other terms,
the Friday/Saturday highs will be two to five degrees above
normal along the coast and in the Umpqua Basin, and five to ten
degrees above normal over the rest of the area.

A trough riding over the ridge will keep temperatures about the
same for Sunday, then the ridge will build in more strongly,
bringing a stronger warming trend to the area Monday through
Wednesday. By Wednesday, highs will be 10-15 degrees above
normal, except around 5-10 degrees above normal over Lake and
Modoc counties. The Medford high may hit 100 degrees as early as
Tuesday.

&&

.AVIATION...For the 22/00Z TAFs...A front is moving over areas
east of the Cascades now and is producing a mix of MVFR and IFR
conditions along and behind it.  Gusty winds are being observed
ahead of the front. Tonight the front pushes east and out of the
forecast area, but enough rain has fallen that we expect the mix of
MVFR and IFR conditions to continue through Thursday morning, most
widespread early in the morning. A much drier air mass will move
into the region on Thursday, and any morning clouds will likely
clear to VFR in the late morning or perhaps early afternoon at
latest. Keene

&&

.MARINE...Updated 200 PM PDT Wednesday 21 August 2019...North winds
will return to the waters tonight as a thermal trough strengthens
inland. Winds will rapidly increase on Thursday, reaching gale
force with very steep hazardous seas south of Cape Blanco Thursday
afternoon and evening. Conditions hazardous to small craft will also
expand north of Cape Blanco.

Late Thursday night into Friday, the thermal trough won`t be as
strong, so gales will most likely end. However, conditions hazardous
to smaller craft are likely to persist. Further weakening of the
thermal trough Friday night into Saturday will cause winds and seas
to lower briefly, but it will strengthen again Sunday with gales
possible again by Monday.

-Spilde/Smith

&&

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

CA...None.

Pacific Coastal Waters...Small Craft Advisory from 5 AM Thursday
        to 11 PM PDT Friday for PZZ350-356-370-376.
     Gale Warning from 11 AM Thursday to 5 AM PDT Friday for
        PZZ356-376.

$$

15/15/20

NWS MFR Office Area Forecast Discussion