753
FXUS66 KMFR 250102
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
502 PM PST Sun Nov 24 2024

.UPDATE...Updated Aviation Discussion.

&&

.DISCUSSION...A low pressure system lingering over the Pacific
continues to dictate conditions over northern California and
southern California. Southerly flow aloft will bring more showers
over Curry County ranges, western Siskiyou County, and the Mount
Shasta region. Snow levels lingering at 4000 to 5000 feet will allow
for snow showers to continue over nigher terrain in these areas.
Southerly flow is also bringing gusty winds into the Shasta Valley
and the southern Rogue Valley. Wind Advisories remain in place for
the Shasta and southern Rogue Valley through 8 PM tonight. A Winter
Storm Warning continues for areas around Mount Shasta above 4000
feet through Tuesday at 4 AM.

Upper level pressure will move eastward, passing over the area
through Monday and Tuesday. Broadly, this will bring increased
shower chances across the area. Snow showers will continue over
those higher elevation areas around Mount Shasta and could develop
over the Cascades on Monday as winds aloft become more westerly.
Moderate to heavy snow is possible around Crater Lake, including
parts of highways 230 and 62. Current forecast snowfall amounts are
borderline for Advisory thresholds in these areas and lower in other
parts of the Cascades. A Winter Weather Advisory will not be issued
as of this moment, but additional data could change that.

Showers and winds taper off through the day Tuesday, with a dry
period in the forecast from Tuesday evening through the weekend
under an upper level ridge. Daytime temperatures do not look to
substantially change, but drier conditions and clear skies will
allow for cooler nights across the area. For Tuesday night through
Saturday night, the Oregon coast is forecast to have lows in the mid
30s to low 40s. West side valleys will be in the mid 20s to mid 30s,
and areas east of the Cascades will be in the low to high tens.

Sunday afternoon and beyond is where confidence starts to falter.
Both ECMWF and GFS long term ensemble outcomes start to show varying
possibilities for Sunday afternoon and beyond, with some staying dry
and others with varying precipitation. At this point, even these
varying possibilities do not look impactful. Meteogram guidance for
Crater Lake snowfall reflects similar possibilities, with no truly
organized signals for heavy snowfall at this point. -TAD

&&

.AVIATION...25/00Z TAFS...Gusty south to southeast winds have
developed here in the Rogue Valley ahead of an occluded front
offshore. Low-level wind shear is still a concern for North Bend and
Roseburg, since surface winds are comparatively much lower than
winds just above the ground (2000 feet). Winds at that level
are in the 30-40 kt range. This risk subsides tonight, but does
persist into the early morning Monday. Since winds aloft are fairly
strong, low-level turbulence can be expected, especially in the
vicinity of terrain. The gusty winds are also being felt over the
east side.

The front offshore is bringing some precipitation inland, but the
steadiest is from the Umpqua Divide to the coast and also in the
vicinity of Mt. Shasta. Overall, ceilings are a mix of VFR/MVFR with
the lowest ceilings in areas of rain/snow. Snow falling near
Mount Shasta will bring IFR and perhaps even LIFR at times
there.

There is a chance that some clearing occurs tonight in Medford. If
this clearing lasts long enough, we could end up with fog again
toward morning. Guidance is mixed in this depiction, so we`ve hinted
at fog potential with the visibility down to around 2SM BR, but
confidence was too low to go with FG at this time.

A second front will push onshore Monday with light precip, mixed
MVFR/VFR ceilings and higher terrain obscurations. Local IFR/LIFR
is possible in heavier precip. -Spilde

&&

.MARINE...Updated 200 PM PST Sunday, November 24, 2024...A small low
is approaching the coast near the Oregon and California border. A
brief period of gales remain possible early this evening. Otherwise,
winds are anticipated to die down with some high and steep seas
tonight. The sea state improves Monday, even as the upper level low
remains over head. Conditions will further improve through the week
as high pressure builds.

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...Wind Advisory until 8 PM PST this evening for ORZ026.

CA...Wind Advisory until 8 PM PST this evening for CAZ081.

     Winter Storm Warning until 4 AM PST Tuesday for CAZ082.

PACIFIC COASTAL WATERS...Gale Warning until 7 PM PST this evening for
     PZZ350-356-370-376.

     Small Craft Advisory from 7 PM this evening to 7 AM PST Tuesday
     for PZZ350-356-370-376.

&&

$$

TAD/DW/CZS/MAS