406
FXUS66 KMFR 311718
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
1018 AM PDT Fri Jul 31 2026

...Aviation Discussion updated...

.KEY MESSAGES...

* Mainly sunny and hot today with highs inland running about 3-7F
  above normal.

* A dry cold front will bring slight cooling Saturday, but also
  breezy to gusty winds, highest east of the Cascades resulting in
  critical fire weather conditions.

* A thermal trough pattern Sunday into early next week will bring
  gusty north to northeast winds to the Umpqua and Illinois
  valleys, and the Oregon coast. Sunday will probably be the
  coolest day for most areas, except SW sections as offshore flow
  develops.

* Temperatures increase early next week, with a warm Chetco effect
  (80s in Brookings) Monday and the hottest temperatures inland
  Tue/Wed, then remaining above normal through Friday.

* Thunder chances remain very low (less than 5%) for the next 7
  days.

&&

.DISCUSSION...Satellite imagery shows mainly clear skies across
the area early this morning with patchy marine stratus, mainly
over the offshore waters, but also affecting some coastal
locations. A strong upper ridge over the Desert Southwest will
nudge toward the area today, so expect plenty of sunshine and
temperatures warmer than yesterday, at least over inland areas
(about 3-7F above normal). Our forecast for Medford is 99F for a
high this afternoon.

Meanwhile, low pressure is centered in the Gulf of Alaska near 51N
and 140W. This system will gradually move east toward the British
Columbia coast and eventually drag a mostly dry cold front across
the area Saturday. From the Cascades west, temperatures should
drop back to near or even slightly below normal levels. A deeper
marine push is expected Saturday morning into the Umpqua Basin
(and also at the coast), so the day will likely begin with lower
stratus. There is even a chance at some drizzle at the coast, but
this is most likely from around Reedsport northward, up around
Florence and/or Newport. Overall, for areas inland west of the
Cascades in SW Oregon, expect highs about 10F lower than on
Friday. We still expect very dry air to persist east of the
Cascades despite a slight cooling trend. With the increase in
wind speeds expected ahead of the front, critical fire weather
conditions should develop in the afternoon/evening. See fire
weather discussion below for more specifics.

After Saturday`s frontal passage, a thermal trough pattern will
set up Sunday into early next week. Sunday will remain cooler
than normal for most and probably will be the coolest day of the
stretch for all but southern and western sections. This pattern
will bring stronger offshore (NNE) winds to areas west of the
Cascades, especially the Umpqua Basin, Illinois Valley and the
coast/coast ranges. This will mean a better chance for winds
aligning with the Chetco and a good shot at a warm Chetco effect
on Monday (highs in the 80s at Brookings). The thermal trough will
likely push inland Tuesday/Wednesday, so it will warm up quite a
bit over the interior with triple digit heat a possibility again
for the Rogue Basin. Uncertainty develops at midweek in terms of
how strong upper ridging will be. Most of the guidance shows a
flatter ridge with temperatures remaining above normal with
moderate heat risk into late next week, but some strengthen the
ridge enough to bring potential for heat related products. We`ll
continue to monitor this. The good news is we still are not seeing
any chance for thunderstorms in the next 7 days (probably even
longer). Models continue to maintain a dry atmosphere with all
the monsoonal moisture remaining bottled up across the Desert
Southwest and Four Corners region. -Spilde


&&


.AVIATION...31/18Z TAFs...VFR prevails areawide through this
afternoon. Along the coast and over the coastal waters, IFR/MVFR
stratus is expected to develop this evening and spread into
northwestern portions of the the Umpqua Basin early Saturday
morning. Current models and guidance keep VFR at Roseburg with MVFR
staying to the northwest. However, there is a low (15%) for MVFR to
develop between 12-17z. Elsewhere, VFR will prevail through the TAF
period.


&&

.MARINE...Updated 300 AM PDT Friday, July 31, 2026...Light to
moderate north winds and seas are expected today, highest south of
Cape Blanco. Low pressure passing to the north will produce
stronger northerly winds Saturday afternoon/evening with steep
seas expected by Saturday night, again south of Cape Blanco.
Gales and very steep seas are highly likely Sunday into Monday
south of Cape Blanco, and periods of storm force gusts possible.
Gusty winds and steep seas look to spread north of Cape Blanco
then. -TAD/Spilde


&&

.FIRE WEATHER...Updated 300 AM PDT Friday, July 31, 2026...The main
fire weather concern will be the passage of a dry cold front
Saturday. As with most dry fronts this time of year, gusty
winds are expected to accompany its passage, with gusts up to 20 mph
expected west of the Cascades, and of 25 to 35 mph to the east.
While the front will bring some slightly improved humidities to the
area (west of the Cascades), conditions will be very close to
critical levels for some locations east of the Cascades,
especially from the Fremont National Forest eastward. As a result,
we have added a Fire Weather Watch to southeast portions of FWZ
624 and all of FWZ 625. We may also last minute include FWZ 285 if
it looks like winds/rh line up there too. Winds should decrease a
bit Sunday. -Spilde


&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...Fire Weather Watch from Saturday afternoon through Saturday
     evening for ORZ624-625.

CA...None.

PACIFIC COASTAL WATERS...Small Craft Advisory from 2 PM Saturday to 5
     PM PDT Sunday for PZZ356-376.

&&

$$