173
FXUS66 KMFR 052331
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
430 PM PDT Fri Jun 5 2026

...Updated AVIATION discussion for 00Z TAFs...

.DISCUSSION...

Cloudy skies are moving inland this afternoon as a surface low
moves into the Pacific Northwest. We also saw a small fire burning
south of Roseburg on the GOES 17 GeoColor RGB this morning,
although it`s not visible this afternoon due to the incoming cloud
cover.

By Saturday morning, the trough will move into northern Oregon and
we`ll have a low chance of rain in areas north of Roseburg in
Douglas and Coos Counties. We`re not expecting rain to spread much
farther south than that. Perhaps in some locations in the coastal
range between Roseburg and Coos Bay. Otherwise, many areas will
likely stay clear farther to the south and east as very little
moisture is present around northern California. With some cooler
air moving in, temperatures will fall to their respective normals
for this time of year.

By Saturday night, frost and freeze becomes a concern east of the
Cascades as this cooler air moves in behind this upper level low.
Temperatures in Klamath Falls will fall into the lower 30`s or
perhaps the upper 20`s. Temperatures in Chemult could fall as low
as the mid 20`s. Depending on one`s exact location, these
temperatures will be a threat to frost sensitive vegetation
Saturday night.

By Sunday, we warm up by about 7 to 10 degrees as high pressure is
in control during the morning hours. The next low and warm front
will approach the Oregon coast during Sunday night. A small
minority(5-10%) of ECMWF ensemble members and the GFS are
spinning up a low off the Oregon coast and bringing a hefty amount
of rain to southern Oregon. The vast majority show a lighter rain
falling with some dry spots in between during the day on Monday.
Another small minority shows some very dry conditions on Monday
with just trace amounts of rain falling over the region. Overall,
we should see rain on Monday, although there is a spread in the
most extreme solutions with some being very dry while others are
relatively wet for early June. We`ll have to wait and see if
things converge in future model runs.

Once this low passes through, we`ll see troughing in the northern
Rockies with deeper north west flow off the Pacific for the
Pacific Northwest. This will keep things on the cooler side with
some showers developing Tuesday evening as another short wave
moves through the area. A thermal trough will likely set up
behind this very deep trough around Thursday or Friday of next
week and push temperatures higher. Heading towards next weekend,
500 mb heights begin to build and move into the 97.5th percentile
by Saturday night. Therefore, we`ll likely be pushing 100 here in
Medford. The NBM only has a 35% chance of surpassing triple digits
at KMFR.


&&

.AVIATION...05/18Z TAFS...VFR levels under high clouds or clear
skies are present across northern California and southern Oregon to
start the TAF period. A system passing to the north will bring
additional cloud cover. Coastal areas are expected to see periods of
MVFR ceilings, while confidence is lower in MVFR ceilings reaching
into the Umpqua Valley. Other areas are expected to stay at VFR
levels under mid to high level clouds. Gusty winds over terrain and
across areas east of the Cascades start to develop towards the end
of the TAF period. -TAD


&&

.MARINE...Updated 235 AM PDT Friday, June 5, 2026...North winds
and seas will lower today, but increase again Saturday afternoon
into Sunday morning, especially south of Gold Beach. South winds
will accompany a front Sunday night into Monday, along with a chance
of rain. Then, light to moderate north winds return Tuesday and
Wednesday. A thermal trough will likely bring marine hazards next
week as stronger north winds and steep to very steep seas
build Thursday into next weekend.

-Smith

&&

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

CA...None.

PACIFIC COASTAL WATERS...None.

&&

$$