847
FXUS66 KMFR 062306
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
406 PM PDT Sun Sep 6 2026

.Aviation discussion updated...

&&

.AVIATION...07/0Z TAFs...Showers and isolated thunderstorms will be
the main aviation hazards through the rest of this evening. While VFR
prevails, visibility will drop to MVFR/IFR thresholds under these
showers and thunderstorms. Precipitation should taper off by
tonight.

Low IFR and LIFR stratus will likely develop near the coast tonight,
including at North Bend (OTH). Those lower ceilings will clear up by
mid morning on Monday with VFR then prevailing through the rest of
the day.


&&

.PREV DISCUSSION... /Issued 145 PM PDT Sun Sep 6 2026/

KEY MESSAGES...

* Showers and thunderstorms continue this afternoon, tapering off
  from west to east during the late afternoon and early evening,
  lingering longest in Lake County.

* Cooler than normal temperatures continue. Where it clears out
  tonight east of the Cascades, a Freeze Warning is in place into
  Monday morning. Frost/freezing temperatures are possible again on
  Tuesday morning.

* A strong warming and drying trend is expected this week with
  high temperatures getting back to normal levels Mon/Tue, and
  then above normal with mid 80s to mid 90s by Wed/Thu.

* Upper trough digging into PacNW late week, but moisture from the
  south gets pinched off and the most likely result is a dry front
  crossing the area Fri/Fri night. Expect some enhanced W-SW
  breezes in advance of this system Thu/Fri, with at least a brief
  cool down Sat. But, precipitation chances look pretty low (5-20%
  range) and mainly NW sections (Cascades N&W).

DISCUSSION...Satellite imagery is showing low pressure swirling
over the PacNW early this afternoon. Colder air aloft is
generating instability along with some showers and even a few
isolated thunderstorms. We can see that much of the west side is
now on the back side of the low/trough as activity is moving from
NW to SE. The axis of the trough is pushing east of the Cascades,
and by this evening, activity will diminish from west to east
(probably by 8 pm near the Cascades and as late as 11 pm over the
East Side).

Drier air will move in pretty quickly behind this system tonight
and clouds should break in most areas. Since the air mass is
pretty cold, areas that clear fastest and remain that way the
longest east of the Cascades will have temperatures drop into the
upper 20s and lower 30s. This has resulted in a Freeze Warning
/PDXNPWMFR/ tonight into Monday morning.

High pressure builds in Monday, but then especially Tuesday
through Thursday resulting a period of strong, warming and
drying. Modest offshore flow (N-NE winds) will occur Monday night
into Tuesday morning due to a strengthening thermal trough. This
will lead to some poor overnight RH recoveries for upper
slopes/ridges of western Siskiyou County and also the coast ranges
through at least midweek. A stronger subsidence inversion should
also lead to one more night (Monday) of valley cold east of the
Cascades with frost and/or freezing conditions. The lower dew
points bring potential for it to be just as cold as tonight. But,
the coldest portion of the air mass aloft will have shifted east
of our area by then. So, the extent of cooling Tuesday will
depend on the characteristics of morning valley inversions. This
probably can handled by a frost advisory. After the chilly start
over there, temperatures rebound closer to normal everywhere by
Tuesday afternoon, then above normal for both Wednesday and
Thursday. It will be warmest for the valleys west of the Cascades
with highs in the 90s both days.

The next upper trough approaches the PacNW Friday, then moves
through Friday night into Saturday. Model solutions are showing a
mostly dry frontal passage, since moisture from the south gets
pinched off and is unable to make it this far north. It`s
conceivable the front could squeeze out a shower or two. But,
probabilities for rain are pretty low (5-20%). Best chances are
from Cascades N&W. The trough should allow for a modest increase
in W-SW breezes in advance of it (beginning Thu pm, but peaking
Fri pm/eve). It should also bring with it a brief cool down with
temperatures around 10-15F below normal for highs on Saturday.
-Spilde

&&

MARINE...Updated 200 PM PDT Sunday, September 6, 2026...Mixed south
and fresh northwest swells will produce low seas today. A thermal
trough develops early Monday, bringing gusty north winds and steep
wind seas south of Port Orford. Steep seas extend to Cape Arago
Monday night, and across the waters Tuesday through Tuesday night.
Winds briefly diminish Wednesday, but steep seas may linger.
Seas hazardous to smaller crafts are likely by Friday and Saturday
as another low and cold front move through the waters.

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...Freeze Warning from 3 AM to 9 AM PDT Monday for ORZ029>031.

CA...Freeze Warning from 3 AM to 9 AM PDT Monday for CAZ082-084-085.

PACIFIC COASTAL WATERS...Small Craft Advisory from 8 AM Monday to 5
     AM PDT Wednesday for PZZ356-376.

     Small Craft Advisory from 11 PM Monday to 5 AM PDT Wednesday for
     PZZ350-370.

&&

$$