Area Forecast Discussion
Issued by NWS Medford, OR

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456
FXUS66 KMFR 211500
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
800 AM PDT Wed Aug 21 2019

.DISCUSSION...21/12Z NAM 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 will
be light, and the bulk of it will fall along the coast and in the
Coast Range. Some 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 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
more typical hot and dry summer pattern will return to the area
over the next few days. Thursday temperature trends will be a
mixed bag though. The north coast and Umpqua Basin, where the
marine layer will have the biggest influence, will see highs near
or a bit below normal. The south coast and the rest of the west
site will see the effects of upper ridging and low level easterly
flow as the thermal trough builds quickly near the coast, and
highs there will bounce up to 2-5 degrees above normal, except for
the Brookings area, which will see highs around 10 degrees above
normal. Meanwhile, the east side will actually be cooler than
Wednesday, with highs near normal.

After that though, all inland areas will see a warming trend into
Saturday, when highs will be 5-12 degrees above normal. A trough
riding over the ridge will bring slightly cooler temperatures to
the area Sunday, then the ridge will build in more strongly,
bringing a stronger warming trend to the area Monday through
Wednesday. By that time, inland highs will be 10-15 degrees above
normal, and the Medford high may hit 100 degrees as early as
Tuesday.

&&

.AVIATION...For the 21/12Z TAFs...MVFR ceilings will start moving
inland this morning and into the afternoon hours along coast.  These
low ceilings will make it to most of the west side valleys, yet the
Rogue Valley and MFR will likely stay VFR for the TAF period.
Regardless, showers will form along the cold front as it pushes
eastward and locations west of the Cascades should see showers for
most of the day.

Cool moist air will linger over the coast and IFR to LIFR CIGS are
likely for most of the day into the early evening hours.  Eventually
VFR conditions should build towards the end of this TAF period as
the trough moves towards the east.

-Smith

&&

.MARINE...Updated 800 AM PDT Wednesday 21 August 2019...Gusty winds
and steep southwest seas will continue through this morning into
this afternoon.  These conditions will be hazardous for smaller
craft through this morning.  Short period waves will ease this
afternoon, but swell will persist into Thursday.

Then, a thermal trough will restrengthen quickly on Thursday with
rapidly increasing north winds and steepening short period seas.
Gale force winds and very steep seas are possible south of Cape
Blanco by late Thursday afternoon/evening, so we have hoisted a Gale
Watch for areas mainly beyond 5NM from shore and south of Port
Orford. Conditions hazardous to small craft will also expand north
of Cape Blanco during this time frame.

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...Gale Watch from Thursday afternoon through
        late Thursday night for PZZ356-376.
     Small Craft Advisory until 11 AM PDT this morning for PZZ370.

$$

15/15/20



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