Small Craft Advisory 5, NWS Medford, OR

Area Forecast Discussion
National Weather Service Medford OR
1020 AM PST Thu Jan 9 2020

.Updated aviation discussion.

.UPDATE...The system that moved through the region last night has
moved well south into southern California. The lingering showers
behind the front have mostly dissipated with a handful of showers
in northern California dissipating at this time. With this have
trimmed back chances of precipitation to just a slight chance in
the Cascades and Douglas and northern Klamath counties. Sven

&&

.PREV DISCUSSION... /Issued 537 AM PST Thu Jan 9 2020/

DISCUSSION...The GFS and SREF models in particular have performed
well with the overnight snowfall. The radar indicates the last of
the main batch of snow showers currently continuing in the
southern portions of Klamath and Lake Counties as well as much of
northern California as our Winter Weather Advisory remains in
effect. Snowfall is still expected to taper off during the next
few hours, lingering longest until around 8 AM in Modoc County.

The forecast is largely consistent with the previous issuance
through the weekend. This includes a period of mainly dry weather
across our area later this morning into early Friday afternoon,
then a wetter and windier conditions with the next cold frontal
system Friday night and post-frontal shortwave disturbances in a
cold northwest flow on Saturday. The recent model trend has
generally been stronger with this set of disturbances. But, more
consistent with what should be a slightly weaker front Sunday
into Sunday night.

As such, the Winter Storm Watch remains in effect for Friday
evening through Saturday afternoon for the southern Oregon
Cascades from Lake of the Woods northward into northern Klamath
County with a snow level around 5000 feet expected to lower to
around 3500 feet. A prominent issue for the day shift will be to
determine if the watch should be expanded into the Siskiyou
Mountains along the Oregon/California border into western Siskiyou
County, or if confidence will allow an upgrade to a Winter Storm
Warning with a possible Advisory level snowfall for the higher
terrain from the remainder of the southern Oregon and northern
California Cascades eastward. The Crater Lake area should take the
prize with the highest snow accumulations of around 2 feet Friday
evening through Saturday afternoon. Besides the snowfall,
southwest winds over the higher terrain and east of the Cascades
(in particular for western Lake County) will be gusty late Friday
afternoon into Saturday morning with peak gusts around 30 to 50
mph.

Winds will not diminish much later Saturday before increasing
again to similar strength Saturday night into Sunday evening,
ahead of and with the next cold frontal system. Lingering and
advance precipitation is likely to be light Saturday night but
then around 12 to 18 inches of Oregon Cascade focused snowfall
Sunday through Sunday night.

Thereafter, there is less confidence in the details but still
high confidence in an active pattern continuing for the remainder
of next week with particular emphasis on much lower than normal
snow levels Monday night into early Wednesday. The best chance
for low elevation valley snow is late Monday night into Tuesday
with the snow level currently forecast at around 1000 feet with
up to 2 inches of valley accumulation with highest amounts of
around 3 to 6 inches in the Oregon Cascades.

Forecast uncertainty increases beginning Wednesday with a wide
spread in the timing, temperature, and strength of the continuing
parade of disturbances.

AVIATION...For the 09/18Z TAF Cycle....IFR/LIFR CIGS/VSBYS is
occurring over the river basins in Coos County with VFR occurring
elsewhere. VFR is expected at all of the primary TAF locations this
afternoon, but MVFR is expected to redevelop along the coast,
especially north of Cape Blanco. Expect terrain obscurations to be
numerous early this morning, diminishing this afternoon under NW
flow over much of the east side and northern California. With a
strong jet stream moving through today, there's likely to be some
turbulent air in the mid to upper levels. Tonight, valley fog and
low ceilings could cause MVFR/IFR for much of the West Side,
including KMFR and KRBG. -Schaaf

MARINE...Updated 445 AM PST Thu 9 Jan 2020...
The low pressure system that moved through overnight into this
morning tracked farther west and south than our preferred model
guidance indicated it would by about 50 NM. This resulted in the
stronger winds and resultant steepest seas remaining mostly west and
south of our coastal waters area. In the wake of the low this
morning, northerly winds will continue to build in behind the
departing low pressure system, but they now appear unlikely to reach
gale force. However, seas will be very steep south of about Gold
Beach beyond about 10 NM of the coast this morning. A lull in the
weather is expected this afternoon into early Friday morning. A
strong frontal system will then move in Friday likely bringing a
brief episode of south gales north of Cape Blanco followed by a
large, long period swell Friday night into Saturday. The latest
guidance has been consistent with the guidance over the last 2 days
in showing northwest swell peaking at 21 to 26 feet at 16 seconds.
More fronts will move in Sunday and throughout next week as the
weather pattern remains very active. ~BTL

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...High Surf Warning from 10 PM Friday to 10 PM PST Saturday for
     ORZ021-022.
     Winter Storm Watch from Friday afternoon through Saturday
     afternoon for ORZ027>030.

CA...None.

Pacific Coastal Waters...Gale Watch from Friday morning through
Friday evening for      PZZ350-370.      Small Craft Advisory until
10 AM PST this morning for      PZZ350-356-370-376.      Hazardous
Seas Watch from Friday morning through Sunday morning      for
PZZ370.      Hazardous Seas Watch from Friday evening through Sunday
morning      for PZZ350-356-376.      Hazardous Seas Warning until
10 AM PST this morning for PZZ376.

SBN/SBN/SBN

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MEDFORD OR
848 AM PST THU JAN 9 2020

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

0847 AM     HEAVY RAIN       2 SSE PISTOL RIVER      42.26N 124.39W
01/09/2020  M1.08 INCH       CURRY              OR   TRAINED SPOTTER

            8 AM TO 8 AM.

&&

SBN