158
FXUS66 KMFR 130556
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
956 PM PST Wed Nov 12 2025

.Updated Aviation Discussion.

.DISCUSSION...The upper ridge that brought the dry, seasonably
mild fall weather across the region the last several days will
shift eastward today. Yesterday was a bit cooler than expected
in some of the valleys that held the fog longer (here in Medford),
but overall, the last 5 days of dry weather have averaged several
degrees above normal.

The pattern changes today as an offshore trough approaches the
coast. There have been some changes in the forecast with respect
to this system over the last 24 hours. We`ll start with what
hasn`t changed -- we are still expecting some gusty south to
southeast winds to develop this afternoon as low pressure
deepens and moves closer, pressure gradients strengthen and
inversions break. MFR-RDD gradient peaks around -6 mb with 700mb
flow increasing from 50-55 kt this afternoon to around 70kt
overnight into Thursday morning. Winds aligning with the Shasta
Valley will be sufficient for high wind warning wind gusts (>58
mph) there. They`ll also align up to around 850 mb over the Rogue
Valley, so we expect some gusty winds from Ashland up to
Medford/Central Point that could exceed advisory levels (>45 mph).
It`ll also get breezy to windy along the coast, but gusts should
be 35-50 mph.

As for the things that HAVE changed -- it appears as if low
pressure will deepen far enough offshore tonight that the
strongest jet max will be farther west. As such, while strong,
gusty south winds are still expected over the East Side (gusts of
50-55 mph), we think they`ll mostly be below warning levels and
have a wind advisory in place. Mountain locations will be windy
and gusts up at Mt. Ashland could be 70+ mph. In addition, since
the low will be farther offshore, snow levels will not come down
as quickly on Thursday, so little or no snow accumulation is
expected, except at the highest peaks. A tricky aspect to this
storm is what happens with the surface low offshore. There are a
couple of possible scenarios, which could have a significant
impact, especially in terms of wind during Thursday. Ensemble
systems are basically split into 2 camps. The EC/Canadian guidance
shows some potential for a deeper low moving northeast (through
our coastal waters) and getting absorbed into the northern branch
flow before weakening Thursday night as it moves into NW Oregon.
The GEFS and NAM, on the other hand, shows the low splitting off
from the northern branch and largely remaining to our south with
the accompanying closed upper low. The EC/Canadian solutions
(which amount to around 40% of the members) would bring the
possibility of high winds to the coast then, while the majority of
the remaining members keep the stronger winds well to the south
and offshore. Right now, while winds can still be gusty along the
coast Thursday, there is a higher probability (~60% chance) for
sub-warning level winds, so we have opted against issuing a high
wind watch. Please note, though, that this is a low confidence
forecast, so we may have to make updates quickly over the next 24
hours.

In terms of rainfall, the heaviest amounts will still be from the
Curry coast and Coast Ranges southeastward into western and
south-central Siskiyou County. Amounts in these locations will
range from 1-3", with the heaviest amounts in the upslope region
of Mt. Shasta, where amounts in some areas could exceed 3 inches
(heaviest overnight into Thursday). Nuisance ponding of water on
roadways could occur in these areas, but we`re not concerned about
flooding at this time. West side valleys are going to see a lot
of downslope rain shadowing, so what looked like a decent storm a
couple of days ago might turn out being a dud. Current forecast
puts most of Medford at or below 0.10" for a storm total, while
surrounding foothills could get 0.25-0.50". Even north coastal
areas look to get much less rainfall.

Some showers could linger Thursday night into Friday as snow
levels finally drop to around 5000-5500 feet, but this is also
MUCH HIGHER than we thought just a couple of days ago. Little or
no accumulating snow is expected in southern Oregon, except maybe
up at Crater Lake (even then amounts are less than 1"). PoPs
lower into Saturday with the bulk of any onshore flow precip
staying mostly to our north.

The next upper trough will approach the coast on Sunday. Models
are showing the closed upper low to the south ejecting to the ENE
across the Great Basin. It appears most of the moisture from that
should stay to our south and east, but could come northward into
the Sierra and maybe NE Cal then. The surface front associated
with the offshore trough should move onshore Sunday night into
Monday. -Spilde/BPN


&&

.AVIATION...13/06Z TAFs...The main aviation hazard for the TAF
period will be low level wind speed shear for the north coast,
including North Bend until around 10z, but could linger for another
hour or two beyond that. Low level wind speed shear in the Umpqua
Basin, including Roseburg is expected to last longer until later
Thursday morning (between18-19z).

Not to downplay the stronger surface winds, but they too will also
be a concern at the Medford terminal with southeast winds that could
exceed 35 kts until Thursday morning. Moderate to strong southwest
at Klamath Falls have dropped off the past few hours, but the
expectation is for winds to increase again tonight, with wind gusts
are likely to get over 35 kts. Guidance shows stronger winds aloft,
so have introduced low level wind speed shear in  the TAF until the
stronger winds surface.

This is all due to a strong front moving towards the area this
evening and tonight.

Most of the rain associated with the front should be mainly in
northern California and offshore as a strong surface low moves
south. This will allow ceilings to remain VFR for most of the TAF
period, although it will be a close call at North Bend late Thursday
morning. However, the higher terrain could be partly obscured along
the Siskiyous and portions of northern California towards 12z.
-Petrucelli


&&

.MARINE...Updated 815 PM PDT Wednesday, November 12, 2025...A
strong front will bring increasing south winds today. These winds
will likely reach gale force this afternoon and continue tonight.
There`s better agreement among the high res models in where the
strongest winds are expected Thursday. The general consensus is for
winds to be strongest from about Bandon south. While winds are
likely to remain below gales north of Bandon, seas are expected to
remain very steep. Therefore the Gale watch has been upgraded to a
warning from early Thursday morning into Thursday afternoon south of
Bandon. At the same time, a Hazardous Seas Warning will be in effect
north of Bandon due to very steep wind driven seas. It`s possible
there could be brief periods of gale force gusts north of Bandon,
especially over the outer waters.

A Small Craft Advisory follows Thursday night into Saturday morning
with northwest swell and fresh southwest swell dominated seas. The
next front is forecast to arrive Sunday with increasing south winds
and seas into Sunday night.


&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...Wind Advisory from 1 AM Thursday to 1 AM PST Saturday for ORZ026-
     029>031.

CA...High Wind Warning until 10 AM PST Thursday for CAZ081.

     Wind Advisory from 1 AM Thursday to 1 AM PST Saturday for CAZ084-
     085.

PACIFIC COASTAL WATERS...Gale Warning until 4 AM PST Thursday for
     PZZ350-356-370-376.

     Gale Watch from late tonight through Thursday afternoon for
     PZZ350-356-370-376.

     Small Craft Advisory from 4 PM Thursday to 4 AM PST Saturday for
     PZZ350-356-370-376.

&&

$$