550
FXUS66 KMFR 231700
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
900 AM PST Sun Feb 23 2025

.DISCUSSION...

Rain has been pretty heavy over the last 18 hours with 4.41 inches
reported by an observer near Gold Beach and 5.71 inches over the
Red Mound RAWS, the wettest station in our CWA. Thats a pretty
healthy rain accumulation amount and rivers are responding
quickly. However, none of them are anticipated to reach minor
flood stage at this point. That could change if the second half of
this atmospheric river event brings more rain that current
anticipated. Otherwise, we`ll see if any wind hazards need to be
fine tuned for Monday. The latest 12Z forecast soundings show some
potential convective instability Monday afternoon in Douglas
County. It`s not out of the question we could see some weak
thunderstorms bring down some stronger winds around that area
Monday.

-Smith

&&

.AVIATION...23/12Z TAFs...Widespread MVFR/IFR prevails from
the coast to the Cascades with areas higher terrain obscured in
light to moderate rain. Freezing levels are high this morning,
generally 7500-8500 feet. VFR/MVFR exists east of the Cascades.
Gusty south winds continue along the coast at North Bend with gusts
up to ~30kt through this afternoon. Low level wind shear (LLWS) is
possible at all TAF sites this morning, but will gradually drop off
later this morning/afternoon as winds aloft weaken. Conditions
generally remain the same tonight with a mix of MVFR/IFR, except
areas of VFR south and east of the Cascades. The next storm
developing offshore will bring LLWS back to North Bend by Monday
morning. Most of the area will have strong, gusty S-SW winds during
Monday and areas of rain/MVFR ceilings. -Spilde


&&

.MARINE...Updated 830 AM PST Sunday, February 23, 2025...Gales
and very steep, hazardous seas persist today. Winds ease briefly
tonight, but seas remain very steep and hazardous. A strong low will
then develop near 130W and move NNEward, then eventually onshore
near the WA/Canadian border, a classic set up for very strong winds
in our coastal waters. We expect widespread strong gales tomorrow
morning and afternoon with a high probability (80-100%) of storm
force (>=55 kt) wind gusts. As such, a Storm Warning is up for that
system. In addition, the strong winds will build extremely steep,
dangerous seas of 20-30 ft, highest in the north off Florence, but
still very steep from Gold Beach southward.

Winds ease from south to north tomorrow night, but very steep seas
will persist into Tuesday. Things should calm down Wednesday, but
guidance has trended higher with a moderate long period west swell
(11-13 ft @ 15-17 seconds) building into the waters Wednesday night
into Thursday. -Spilde/Hermansen

&&

.BEACH HAZARDS...Updated 830 AM PST Sunday, February 23, 2025...
Strong storm force winds will affect the marine waters tomorrow.
This will quickly build dangerous seas. When combined with an
increasing west swell, this will result in breaking wave heights of
25 to 32 ft tomorrow afternoon into Tuesday morning. A High Surf
Warning is in effect north of Port Orford where the largest breaking
waves are expected with a High Surf Advisory south of there.
Hazardous beach conditions are expected during this time, and these
large breaking waves could inundate beaches and low lying
structures. Beach erosion will be possible, and exposed
infrastructure may be damaged. Avoid area beaches during this storm
Monday. -Spilde/Hermansen

&&

.PREV DISCUSSION... /Issued 413 AM PST Sun Feb 23 2025/

DISCUSSION...A solid shield of rain covers all areas from the
Cascades to the coast. This area of moderate to heavy rain will
continue to spread east today and persist through tonight, so our
friends east of the Cascades will see some moisture as well.
However, due to rain shadowing, amounts there will be much less
than the general 1 to 2 inches expected to the west, and
definitely much lower than the 4 to 6 inches expected along the
coastal ranges.

With snow levels close to 9000 feet, essentially all areas will
see rain through the weekend, with rain falling on the heavy snow
along and east of the Cascades. There is concern the flooding
risk could be higher in that section of our area near Chemult and
Crescent with 1 inch of rain falling on all the snow, especially
due to ponding on area roadways where drainages are blocked.
However, the snow can absorb most of that rain, so the rivers are
not expected to rise rapidly or even hit action stage at this time.
It will be something to keep an eye on, just in case.

Rain will linger tonight into Monday morning as the surface
boundary wobbles back to the north, but by this time, moisture
inflow is expected to wane and precipitation rates will be on the
downswing. The next system then swings back through Monday
afternoon, but the main concern this time will be wind.

A rapidly deepening surface low is forecast to pass inside 130W,
and the sea level pressure gradient will tighten significantly
along the coast (now expected to be -10 to -11 mb between North
Bend and Arcata, up a tic or two since just yesterday). These are
the main ingredients we typically look for in a strong wind event,
and nearly all ensemble suites and guidance depict this event s a
significant wind storm for our area, even in many areas that are
typically sheltered from stronger winds. This is due to the timing
of the event, occuring during the afternoon and evening when
daytime mixing is strongest, and winds from upper levels can be
transported to the surface. High Wind Warnings have been issued
for the coast, the East Side, and the Shasta Valley, with a
widepsread Wind Advisory now in place for the West Side.
Additional areas may need to be added to these headlines over the
next 24 hours as the system gets closer to the area and models
better resolve the situation. Details on the wind headlines can
be found at PDXNPWMFR.

Snow levels Monday will start well above 5000 feet, but will lower
to around 4000 feet behind the passing front Monday night.
Lingering post-frontal showers are then expected to drop another
1-3 inches of snow Monday night on top of what should then be a
soggy snowpack along the higher terrain of the area, as well as
along the 97 corridor just east of the Cascades.

High pressure will begin to build Tuesday afternoon and persist
into Wednesday over southern Oregon and northern California with
dry conditions Temperatures will begin to feel more spring like
with highs in the mid 60`s west of the Cascades and upper 50`s
east of the Cascades. These highs are about 10 degrees warmer than
normal for this time of year.

Ensembles are then predicting a low chance of precipitation towards
Thursday as an upper level wave or cutoff low pushes into
southern Oregon, or splits to the north and south. Precipitation
will likely be light with the QPF under 0.01 inches Thursday, all
confined to areas west of the Cascades.

Dry conditions then return for the end of the week, followed by
another potentially wet system next weekend. -BPN

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...High Wind Warning from 10 AM to 7 PM PST Monday for ORZ021-022-
     030-031.

     Flood Watch through Monday morning for ORZ021-022.

     High Surf Warning from 10 AM Monday to 10 AM PST Tuesday for
     ORZ021.

     High Surf Advisory from 10 AM Monday to 10 AM PST Tuesday for
     ORZ022.

     Wind Advisory from 10 AM Monday to 1 AM PST Tuesday for
     ORZ023>026.

CA...High Wind Warning from 10 AM to 7 PM PST Monday for CAZ081-085.

PACIFIC COASTAL WATERS...Gale Warning until 4 PM PST this afternoon
     for PZZ350-356-370-376.

     Hazardous Seas Warning from 4 PM this afternoon to 4 AM PST
     Monday for PZZ350-356-370-376.

     Storm Warning from 4 AM to 7 PM PST Monday for PZZ350-356-370-
     376.

&&

$$