394
FXUS66 KMFR 181007
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
307 AM PDT Mon Aug 18 2025

.DISCUSSION...Satellite imagery and surface observations this
morning show patchy to widespread low clouds over much of the area
along and west of the Cascades, with some spilling over into the
Klamath Basin as well. Once the sun rises, these areas will burn
off through the morning, with scattered clouds expected through
the afternoon, then mostly clear skies tonight.

Those will be the first of several days of mostly clear skies as
the upper level trough pushes out of the area, and upper level
ridging attempt to push in from the east. This will keep stable
southwest flow over the region today into Tuesday, which will
keep afternoon temperatures in check with values near seasonal
norms for the interior.

From mid week on, the upper level "Four-Corners" ridge will
strengthen and nudge farther into our area with continued dry
weather and the redevelopment of the coastal thermal trough. It
will start to heat up Wednesday with hot weather likely through
the remainder of the week. Expect afternoon highs in the upper
90s for the interior valleys Thursday, followed by triple digit
readings through the weekend. East of the Cascades, it will be in
the upper 80s to low 90s the latter part of next week into next
weekend.

One thing we`ll have to watch closely is the potential for some
monsoonal moisture to make its way from the south into portions of
the East Side starting as early as Friday into next weekend. It`s
too early to know if there will be sufficient moisture to support
thunderstorms, but many of the ensemble members are beginning to
nudge precipitation chances into Modoc and Lake counties at times.
Expect updates over the coming forecast cycles. -BPN/Petrucelli

&&

.FIRE WEATHER...Updated 200 PM PDT Sunday, August 17,
2025...Saturday`s front had observations of 0.20 and 0.50 inches of
rainfall for coastal areas and elevated terrain (including east side
areas). West side valleys generally got 0.10 inches of rain or less.

Showers have been few today and isolated today. Thunderstorm chances
remain in the forecast this afternoon and evening. Forecast coverage
has decreased to western Siskiyou County and easternmost Lake and
Modoc counties. Any activity that does develop is expected to be
isolated and should dissipate into the evening.

A pattern change to southwest flow aloft on Monday will bring drier
air aloft, minimizing the chances of activity continuing into the
week. Daytime highs look to reach seasonal levels early in the week.
Midweek, high pressure over the Four Corners looks to build a ridge
that will start to could move over the area. This would support
daytime highs rising above seasonal levels. Current guidance shows
that most west side valleys (Umpqua Valley excluded) could see near
or just above triple digits by Friday or Saturday. Dry daytime
conditions are expected, but current overnight recoveries look to
remain moderate. Periods of overnight easterly flow could bring
locally poor recoveries, but this is not supported in current
forecast values. An upper level disturbance that looks to pass over
the area on Wednesday is also worth paying attention to, as these
disturbances can sometimes bring gusty to breezy winds. These
elevated winds are also not currently expected. Overall, hazardous
fire weather conditions are not expected but some factors may bring
elevated concerns through the dry period. -TAD

&&

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

CA...None.

PACIFIC COASTAL WATERS...None.

&&

$$