460
FXUS66 KMFR 292331
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
431 PM PDT Wed Jul 29 2026

...Updated Aviation Discussion...

.KEY MESSAGES...

* Very low(<5%) chance of a thunderstorm around Lake and Klamath
  Counties Thursday.

* Temperatures warm up on Friday.

* Dry cold front stalls out over southern Oregon on Saturday with
  winds trending higher and cooler temperatures in some areas.

* Temperatures heat up Monday and Tuesday with moderate heat risk
  in valleys west of the Cascades.

&&

.DISCUSSION...

Another strong marine push has kept temperatures in check around
the coastal valleys and the Umpqua Valley of this afternoon. These
clouds will eventually break up by the late afternoon with most
areas still rising into the 80`s. The short wave we`ve been
monitoring for the last few days has pushed into northern Oregon,
so we`ll miss out on any thunderstorms this afternoon and evening.
Most of the smoke from the Castle fire continues the daily push
east in the afternoon and evening before settling and draining
down the Cascade foothills in Douglas County.

The story remains the same on Thursday as another short wave is
anticipated to swing through Oregon during the afternoon and
evening under this west to southwest flow. The convecting
allowing models in the HREF are not anticipating any convective
activity. Meanwhile, a few ECMWF members are showing hints at
something. Overall, the chances of a weak shower or isolated
thunderstorm remain under 5% in northern Lake and Klamath Counties
Thursday afternoon.

High temperatures trend warmer by roughly 5 degrees on Friday to
around 98 here in Medford. The NWS heat risk algorithm is
suggesting pockets of moderate heat risk in some valleys.
Moderate heat risk impacts those exposed to the elements and those
most sensitive to heat exhaustion. Overall, there are minimal
impacts due to the heat on Friday as we nudge a few degrees warmer
than normal.

Saturday is the big change still with models
forecasting a strong dry cold front pushing through the Pacific
Northwest. The front kind of sags and stalls out when it gets to
our forecast area by Saturday evening. The NBM is lowering high
temperatures by about 5 to 10 degrees with the higher drops around
Coos and Douglas Counties. Since the front does stall a bit,
Modoc and portions or southern Lake or Siskiyou won`t see any
change in temperatures on Saturday. We should also see winds pick
up a bit by the afternoon and evening hours, although it shouldn`t
be impactful.

With all this colder air moving in behind the front, the extreme
forecast index(EFI) was picking up on unusually cold temperatures
Saturday night with EFI values around -0.6 to -0.8 for late July.
We are forecasting some lows in the mid 30`s around Chemult and
perhaps sub freezing temperatures south of Chemult in the Klamath
Marsh area. The cooler than normal temperatures will continue
through the weekend as an upper level wave progresses through the
Pacific Northwest. However, this colder air will be short lived.

Some upper level energy from the aforementioned wave will swing
through Washington Sunday night with another dry cold front flying
down the Oregon coast. Pressure gradients help kick off a thermal
trough and temperatures warm up west of the Cascades Monday
afternoon as high pressure builds. That thermal trough will linger
into Tuesday and perhaps Wednesday as Medford is expected to hit
100 degrees on both days. Both the ECMWF and GFS want to push
the thermal trough eastwards towards the end of Wednesday, so
we`ll see if we can get some stronger onshore flow towards the end
of the week next week.

-Smith

&&

.AVIATION...30/00Z TAFs...Local MVFR in marine stratus remains along
the Oregon coast, mainly inland and south of North Band. This
stratus may clear late today. Then, MVFR/IFR in stratus is expected
to return to the coast between 05-09z and persist through around
18z. This will mainly affect areas north of Cape Blanco and
Brookings south.

High clouds are expected to move into southwest Oregon Thursday
morning. This will likely keep MVFR ceilings from developing in the
Umpqua Basin. Current guidance keeps Roseburg VFR through the TAF
period. The National Blend of Models guidance shows a 30% chance for
MVFR at Roseburg though. So, we will monitor this.

Elsewhere, inland areas are expected to remain at VFR levels with
clear skies and normal diurnal breezes for most of the TAF period.

&&

.MARINE...Updated 130 AM PDT Wednesday, July 29, 2026...North winds
will gradually increase today, reaching advisory criteria south of
Port Orford and beyond 10 nm from shore. This will bring borderline
steep seas Wednesday, primarily from Gold Beach southward. Winds
ease on Thursday with improved conditions expected through early
Saturday.

On Saturday, a low pressure system passing to the north may bring
very strong northerly winds over area waters as it tightens the
gradient and enhances the thermal trough. Although the timing and
strength of these winds are uncertain, the latest models are showing
a high likelihood of gales and very steep seas, and nearly a 40
percent chance of storm force gusts by early next week. -TAD/BPN

&&

.FIRE WEATHER...Updated 230 PM PDT Wednesday, July 29, 2026...

Overall, the rest of the week will see generally normal summer
weather but with some conditions worth addressing. Very slight
chances (About 5%) remain for afternoon/evening dry thunderstorms
east of the Cascades for today and Thursday. Friday looks to be the
warmest day of the week, with temperatures about 5 degrees above
normal before cooling to about 5 degrees below normal over the
weekend.

A dry cold front is bringing elevated fire weather concerns for
Saturday, as this front looks to bring strengthened northwest winds
across the area. The highest winds will likely be along coastal
headlands and across the east side, but the Shasta and eastern Rogue
(From Shady Cove to Gold Hill to Ashland) may see gusty winds funnel
through. Details are coarse at this point, but currently winds stay
short of critical speeds and RHs see a slight increase while wind
speeds are at their highest. This period will be watched closely as
the details resolve. -TAD


&&

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

CA...None.

PACIFIC COASTAL WATERS...Small Craft Advisory until 8 PM PDT this
     evening for PZZ376.

&&

$$