826
FXUS66 KMFR 272331
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
431 PM PDT Thu Mar 27 2025

...New Aviation Section...


.AVIATION (00Z TAFs)...

Ceilings will be a mix of VFR and MVFR as showers continue across
the forecast area. The main issue through this cycle will be
the timing of showers at the terminals which will essentially
cause fluctuating ceilings as a result. Wind speeds are expected
to calm down later tonight, but breezy wind speeds are still
possible until the atmosphere starts to decouple later tonight.

-Guerrero

&&

.PREV DISCUSSION... /Issued 236 PM PDT Thu Mar 27 2025/

DISCUSSION...Precipitation continues to stream into the area as
the large, strong low spins just offshore. Meanwhile, widespread
gusty winds have been reported across the region, with a few power
outages reported earlier this afternoon. This prompted the
issuance of a Wind Advisory for much of the West Side, expanding
upon the smaller advisory issued just for the southern Rogue
Valley. High Wind Warnings continue for the coast and the Shasta
Valley, as well as for portions of the East Side (along with a
Wind Advisory) through this evening and tonight. Details on these
can be found at PDXNPWMFR. While the strongest winds taper off
tonight, gusty winds and breezes will continue through Friday.

Snow remains a concern as well this afternoon, with Winter Weather
Advisories in place for areas above 4500 feet in western Siskiyou
County and along the Oregon Cascades in the vicinity of and north
of Crater Lake through tonight. Details on these can be found at
PDXWSWMFR.

The offshore low will slowly make its way east today, then spin
off to the north and merge with the next low in the sequence that
will arrive offshore this weekend. This will keep onshore cyclonic
flow in place and therefore keeping showers and rain ongoing
through tonight and  Friday. Then, as the low spins off to the
north, a shortwave will pass onshore and enhance the showers
Friday afternoon and evening. Once this wave passes, precipitation
will taper off through early Saturday morning, and breezy winds
will finally begin to calm.

After a brief break in the action Saturday afternoon and evening,
the second offshore low will approach the coast with more wind and
rain Saturday night into Sunday. Snow levels are expected to
remain above roughly 4500 feet again, so winter weather concerns
will be limited. Also, the moisture inflow with this system
appears to be much less robust than the current one today, so
rainfall amounts will trend lower, although once again, activity
will continue for an extended period of time.

Beyond Sunday and heading through much of next week, the model
solutions vary quite a bit on the details of any approaching
systems. However, there does appear to be a strong trend of
continued cyclonic flow, or "troughiness," with onshore flow,
which suggests that showers will be continuing through much of the
week. Temperatures will also trend just slightly below normal due
to ongoing cloudiness and the cooler air mass aloft. We will
continue to monitor the models, however, as there are some
indication of a stronger system possible roughly midweek, although
current trends suggest it is likely to be aimed to our south in
central California. -BPN

AVIATION...27/18Z TAFs...Convective showers are mainly concentrated
along the south coast, and coastal mountains which have resulted in
lower ceilings with the terrain at least partly obscured. This is
expected to be the cast through at least 12z tomorrow  morning.

The main concern to start is low level wind speed shear until the
stronger winds aloft mix down near the surface in the valleys west
of the Cascades in Oregon. This has already happened along the
coast, including North Bend. The stronger winds should surface at
Roseburg between 20-21z, and Medford, although it`s possible it
could be delayed at Medford until after 22z.

Once the stronger winds surface west of the Cascades, it will remain
windy at the terminals because we`ll be in a convective environment,
with gusty winds lasting into at least 6z this evening. Winds will
diminish some tonight, but it will remain breezy.

Strong winds east of the Cascades will continue into tonight. Winds
at Klamath Falls is already gusting to 38 knots as of writing this
discussion and it could gust as high as 45 kts this afternoon.

As previously mentioned, the lower ceilings into this afternoon will
be confined to the coast, and coastal mountains with MVFR and IFR
ceilings/visibility with the terrain obscured. Farther inland, VFR
ceilings are expected to be the predominate condition through for
most of the TAF period. However the higher terrain could be partly
obscured after 22-23z due to convective showers. -Petrucelli

MARINE...Updated 200 PM Thursday, March 27, 2025...A strong surface
low is just inside of 130W. The latest ASCAT pass (which is a
satellite derived wind speed observation) from last night shows
solid Gales over the waters, and this is confirmed by what the buoy
observations are showing. Storm Force winds are still in the cards
this afternoon.

Winds will shift southwest and gradually diminish early this and
tonight, but Gale Force winds will follow the Storm Force winds this
evening, followed by Hazardous Seas Warning conditions through
Friday afternoon.

A heavy long period west swell at 14-15 seconds with very high and
dangerous seas of 25 to 30 ft will follow later this evening.

We could catch a brief break in the weather Friday night into
Saturday, but seas could hover near 10 feet. Seas will then drop
below 10 feet Saturday night into Sunday morning, but another strong
front is possible Sunday into Monday. This front could move just
south of the region which would limit the strength of winds and
height of the seas. Stay tuned as details become clearer over the
coming days. -Petrucelli

BEACH HAZARDS...Updated 200 PM Thursday, March 27, 2025...A long
period swell from the southwest (about 220 degrees) will result in
large breaking waves along the beaches. Surf heights will be around
28 to 33 feet into the evening. Surf will reach peak heights this
afternoon. Surf heights will decrease later tonight, but remain very
high into Friday morning.

These extremely large breaking waves will create very hazardous
conditions along beaches and area shorelines. Waves will inundate
beaches and surge into normally dry areas. Infrastructure damage and
significant beach erosion can be expected. Beaches and coastlines
will become dangerous due to very large and life-threatening surf
conditions. Stay off of beaches, rocks, jetties, piers, and other
waterside infrastructure. -Petrucelli

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...Winter Weather Advisory until 11 AM PDT Friday for ORZ027.

     High Wind Warning until 11 PM PDT this evening for ORZ021-022-
     030-031.

     Wind Advisory until 5 AM PDT Friday for ORZ023-024-026-029>031.

     High Surf Warning until 11 AM PDT Friday for ORZ021-022.

CA...Winter Weather Advisory until 11 AM PDT Friday for CAZ080.

     High Wind Warning until 11 PM PDT this evening for CAZ081-085.

     Wind Advisory until 5 AM PDT Friday for CAZ084-085.

PACIFIC COASTAL WATERS...Storm Warning until 5 PM PDT this afternoon
     for PZZ350-356-370-376.

     Gale Warning until 11 PM PDT this evening for PZZ350-356-370-
     376.

     Hazardous Seas Warning from 11 PM this evening to 11 PM PDT
     Friday for PZZ350-356-370-376.

&&

$$