Winter Weather in Oregon, November 19, 2020

Area Forecast Discussion
National Weather Service Medford OR
850 AM PST Thu Nov 19 2020

.SHORT TERM...Showers are decreasing over the area this morning
and have become light. So we have ended the winter weather
advisory for the mountains. Overnight moderate rain and snow
fell, especially from the Cascades west and over the mountains.
There were light to moderate snow accumulations across the
Southern Oregon Cascades and higher terrain on the east side
overnight. Roads may remain icy to snow covered across these
passes this morning with light isolated to scattered showers and
cold temperatures. Otherwise, expect high pressure to build into
the area today and remain in place through Saturday night,
resulting in drying weather. With stable conditions and light
winds, areas of fog and freezing fog are expected to develop
across inland valleys tonight/Friday morning and again Friday
night/Saturday morning. This includes western valleys such as the
Coquille, Umpqua, Illinois, Applegate, Rogue and Lower Klamath
River Valleys as well as areas on the east side such as the
Klamath Basin and near Alturas.

&&

.AVIATION...For the 19/12Z TAFS...Scattered showers will end later
this morning. Until then, there will be areas of MVFR cigs/vsbys
with higher terrain obscured. VFR conditions will develop everywhere
by Thursday afternoon and will persist through Thursday evening.
Areas of IFR cigs/vsbys in fog/freezing fog and low clouds will
develop late Thursday night, mostly over the west side valleys.
The lower conditions will persist into Friday morning, clearing to
VFR by late Friday morning.

&&

.MARINE...Updated 800 AM PST Thursday 19 Nov 2020...Winds and seas
will diminish today, but seas will remain steep into the afternoon.
High pressure will build Friday along with a trough near the coast.
This will bring gusty north winds and steep seas to areas south of
Cape Blanco Friday afternoon into Saturday evening. The trough will
weaken Saturday night. The first in a new series of fronts will move
onshore early Sunday with more fronts following through the middle
of next week. Seas will likely trend higher through the middle of
next week.

&&

.PREV DISCUSSION... /Issued 320 AM PST Thu Nov 19 2020/

SHORT TERM...Another morning of active weather with upper level
troughing over the region. The last shortwave in the series is
currently moving through the area, bringing another round of
showers with snow showers above 3500-4000 ft. Area webcams show
some snow covered roads along the Cascades from Lake of the Woods
northward and also along Hwy 97 north of Hwy 138 in the
Chemult/Crescent area. Snow is expected to continue impacting
these areas with periods of moderate to heavy snowfall through
this morning as showers move through the area. A Winter Weather
Advisory (WSWMFR) remains in effect for this through 10 am so if
you are traveling through this area this morning, be prepared for
wintry travel conditions. In addition, winds remain gusty across
the higher terrain and portions of the East Side where gusts in
the 30 to 40 mph range are common. A Wind Advisory (NPWMFR)
remains in effect for this as 700 mb winds peak at 35 to 45 knots
in these areas through this morning. These winds combined with
snow fall could lead to some reduced visibilities at times through
this morning.

The weather will be quieting down as the day progresses today. Winds
will begin to diminish early this morning and showers will taper off
by late morning. Afterwards, most areas will remain dry this
afternoon and evening. There may be some isolated showers that
linger along the coast and over the coastal waters, but even those
should come to an end by late this evening.

Cloudy skies this morning will gradually give way to sun for most
areas as drier air moves into the region and we enter a period of
dry conditions under short term ridging. This break in the weather
is expected to continue through Saturday night with the next front
expected to arrive at the coast early Sunday morning. In the
meantime, expect valley fog/freezing fog during the overnight and
morning periods as strong inversions develop. Fog and low clouds may
linger into the afternoon hours for some locations, which would lead
to some chilly days. However, the area will be under east to
northeasterly flow during this time. This may may help limit the
duration of fog and low clouds if these winds can mix down. On the
other hand, depending on the strength of these inversions, these
winds may just blow right over the valleys. If the former occurs,
temperatures will be on the warmer side with more sunshine. If the
latter occurs, then daytime highs may end up lower than what is
currently forecast. /BR-y

LONG TERM...(From Wednesday Afternoon's AFD)...Saturday through
Wednesday Night...The forecast area will remain in an active
pattern throughout the extended period, with alternating periods
of ridging and troughing aloft. No individual system during the
next week appears particularly strong, but each front will produce
a chance of rain and snow, continuing our wet trend this month.
During the periods of high pressure, strong valley inversions are
likely to keep fog and/or low stratus clouds in many valleys,
especially west of the Cascades, through the overnight hours and
into the mornings, perhaps even into the afternoons.

The first front arrives Sunday, but the bulk of the energy and
moisture associated with the system is likely to pass just to our
north. Snow levels of between 4000 and 5000 feet are expected, and
will precipitation is likely, especially along and west of the
Cascades, this is not expected to be a particularly strong rain or
snow producer. A second front will arrive Monday, but looks even
less impressive in terms of moisture. Snow levels, however, should
lower to around 3000 feet as it arrives early Monday morning, so
some of the higher passes could see brief impacts during the morning
commute. After a brief break Tuesday, another front is possible
Wednesday, although again it appears likely to be another glancing
blow, with most precipitation falling to our north. -BPN

&&

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

CA...None.

Pacific Coastal Waters...Small Craft Advisory until 4 PM PST this afternoon for
     PZZ350-356-370-376.
     Small Craft Advisory from 10 AM Friday to 10 PM PST Saturday for
     PZZ356-376.

CC

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MEDFORD OR
803 AM PST THU NOV 19 2020

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0800 AM     HEAVY RAIN       10 NNW GOLD HILL        42.57N 123.09W
11/19/2020  M1.48 INCH       JACKSON            OR   TRAINED SPOTTER

            24 HOUR TOTAL.

&&

BPN