Winter Storm Watch 9, NWS Medford, OR

851 
WWUS46 KMFR 141230
WSWMFR

URGENT - WINTER WEATHER MESSAGE
National Weather Service Medford OR
430 AM PST Tue Dec 14 2021

CAZ082-083-142030-
/O.CON.KMFR.WS.A.0009.211215T1500Z-211216T0600Z/
South Central Siskiyou County-
North Central and Southeast Siskiyou County-
Including the cities of Dunsmuir, McCloud, and Mount Shasta
430 AM PST Tue Dec 14 2021

...WINTER STORM WATCH REMAINS IN EFFECT FROM WEDNESDAY MORNING
THROUGH WEDNESDAY EVENING...

* WHAT...Heavy snow possible. Total snow accumulations of 5 to 
  12 inches possible. Winds could gust as high as 40 mph, 
  especially for areas north of Mount Shasta City.

* WHERE...South Central Siskiyou County and North Central and 
  Southeast Siskiyou County. This includes portions of 
  Interstate 5 south of Weed portions of highway 89. This also 
  includes the communities of Mount Shasta City, Dunsmuir, 
  McCloud as well as rural areas east of Mount Shasta City and 
  south of Tennant.

* WHEN...From Wednesday morning through Wednesday evening.

* IMPACTS...Travel could be very difficult to impossible. Patchy 
  blowing snow could significantly reduce visibility. The 
  hazardous conditions could impact the morning or evening 
  commute. Gusty winds could bring down tree branches.

* View the hazard area in detail at 
  https://www.wrh.noaa.gov/map/?wfo=mfr

PRECAUTIONARY/PREPAREDNESS ACTIONS...

* Stock emergency kit with tire chains, flashlight, batteries, 
  blankets, food, water, and medications.

* The safest place during a winter storm is indoors.

* Plan now to avoid traveling during the storm.

* A Winter Storm Watch means there is potential for significant 
  snow accumulations that may create dangerous travel.

&&

$$

CAZ080-142030-
/O.CON.KMFR.WS.A.0009.211215T1500Z-211216T0600Z/
Western Siskiyou County-
Including the cities of Callahan and Etna
430 AM PST Tue Dec 14 2021

...WINTER STORM WATCH REMAINS IN EFFECT FROM WEDNESDAY MORNING
THROUGH WEDNESDAY EVENING ABOVE 3000 FEET...

* WHAT...Heavy snow possible above 3000 feet. Total snow 
  accumulations of 5 to 12 inches possible. Winds could gust as 
  high as 45 mph.

* WHERE...Western Siskiyou County. This includes portions of 
  highway 3 near Callahan, higher portions of Sawyers Bar Road 
  and the community of Etna. This also includes higher terrain 
  in western Siskiyou County.

* WHEN...From Wednesday morning through Wednesday evening.

* IMPACTS...Travel could be very difficult to impossible. Patchy 
  blowing snow could significantly reduce visibility. The 
  hazardous conditions could impact the morning or evening 
  commute. Gusty winds could bring down tree branches.

* View the hazard area in detail at 
  https://www.wrh.noaa.gov/map/?wfo=mfr

PRECAUTIONARY/PREPAREDNESS ACTIONS...

* Stock emergency kit with tire chains, flashlight, batteries, 
  blankets, food, water, and medications.

* The safest place during a winter storm is indoors.

* Plan now to avoid traveling during the storm.

* A Winter Storm Watch means there is potential for significant 
  snow accumulations that may create dangerous travel.

&&

$$

Visit us at https://www.weather.gov/Medford

285 
WWUS46 KMFR 142025
WSWMFR

URGENT - WINTER WEATHER MESSAGE
National Weather Service Medford OR
1225 PM PST Tue Dec 14 2021

CAZ082-083-150000-
/O.CON.KMFR.WS.A.0009.211215T1500Z-211216T0600Z/
South Central Siskiyou County-
North Central and Southeast Siskiyou County-
Including the cities of Dunsmuir, McCloud, and Mount Shasta
1225 PM PST Tue Dec 14 2021

...WINTER STORM WATCH REMAINS IN EFFECT FROM WEDNESDAY MORNING
THROUGH WEDNESDAY EVENING...

* WHAT...Heavy snow possible. Total snow accumulations of 5 to 
  12 inches possible. Winds could gust as high as 40 mph, 
  especially for areas north of Mount Shasta City.

* WHERE...South Central Siskiyou County and North Central and 
  Southeast Siskiyou County. This includes portions of 
  Interstate 5 south of Weed portions of highway 89. This also 
  includes the communities of Mount Shasta City, Dunsmuir, 
  McCloud as well as rural areas east of Mount Shasta City and 
  south of Tennant.

* WHEN...From Wednesday morning through Wednesday evening.

* IMPACTS...Travel could be very difficult to impossible. Patchy 
  blowing snow could significantly reduce visibility. The 
  hazardous conditions could impact the morning or evening 
  commute. Gusty winds could bring down tree branches.

* View the hazard area in detail at 
  https://www.wrh.noaa.gov/map/?wfo=mfr

PRECAUTIONARY/PREPAREDNESS ACTIONS...

* Stock emergency kit with tire chains, flashlight, batteries, 
  blankets, food, water, and medications.

* The safest place during a winter storm is indoors.

* Plan now to avoid traveling during the storm.

* A Winter Storm Watch means there is potential for significant 
  snow accumulations that may create dangerous travel.

&&

$$

CAZ080-150000-
/O.CON.KMFR.WS.A.0009.211215T1500Z-211216T0600Z/
Western Siskiyou County-
Including the cities of Callahan and Etna
1225 PM PST Tue Dec 14 2021

...WINTER STORM WATCH REMAINS IN EFFECT FROM WEDNESDAY MORNING
THROUGH WEDNESDAY EVENING ABOVE 3000 FEET...

* WHAT...Heavy snow possible above 3000 feet. Total snow 
  accumulations of 5 to 12 inches possible. Winds could gust as 
  high as 45 mph.

* WHERE...Western Siskiyou County. This includes portions of 
  highway 3 near Callahan, higher portions of Sawyers Bar Road 
  and the community of Etna. This also includes higher terrain 
  in western Siskiyou County.

* WHEN...From Wednesday morning through Wednesday evening.

* IMPACTS...Travel could be very difficult to impossible. Patchy 
  blowing snow could significantly reduce visibility. The 
  hazardous conditions could impact the morning or evening 
  commute. Gusty winds could bring down tree branches.

* View the hazard area in detail at 
  https://www.wrh.noaa.gov/map/?wfo=mfr

PRECAUTIONARY/PREPAREDNESS ACTIONS...

* Stock emergency kit with tire chains, flashlight, batteries, 
  blankets, food, water, and medications.

* The safest place during a winter storm is indoors.

* Plan now to avoid traveling during the storm.

* A Winter Storm Watch means there is potential for significant 
  snow accumulations that may create dangerous travel.

&&

$$

Visit us at https://www.weather.gov/Medford

911 
WWUS46 KMFR 142212
WSWMFR

URGENT - WINTER WEATHER MESSAGE
National Weather Service Medford OR
212 PM PST Tue Dec 14 2021

CAZ083-151400-
/O.UPG.KMFR.WS.A.0009.211215T1500Z-211216T0600Z/
/O.NEW.KMFR.WW.Y.0033.211215T1200Z-211216T0600Z/
/O.NEW.KMFR.WS.W.0012.211215T1200Z-211216T0600Z/
North Central and Southeast Siskiyou County-
Including the cities of Pondosa and Tennant
212 PM PST Tue Dec 14 2021

...WINTER STORM WARNING IN EFFECT FROM 4 AM TO 10 PM PST
WEDNESDAY...
...WINTER WEATHER ADVISORY IN EFFECT FROM 4 AM TO 10 PM PST
WEDNESDAY...

* WHAT...For the Winter Storm Warning, heavy snow expected. Total
  snow accumulations of 6 to 12 inches. Winds gusting as high as
  60 mph. For the Winter Weather Advisory, snow expected. Total
  snow accumulations of 3 to 6 inches. Winds gusting as high as 
  60 mph.

* WHERE...For the Warning, high terrain areas including the Shasta
  Medicine Lake highlands. For the Advisory, Tennant.

* WHEN...From 4 AM to 10 PM PST Wednesday.

* IMPACTS...Travel could be very difficult. Blowing snow could 
  significantly reduce visibility. The hazardous conditions could 
  impact the morning or evening commute. Strong winds could cause 
  tree damage.

* View the hazard area in detail at 
  https://www.wrh.noaa.gov/map/?wfo=mfr

PRECAUTIONARY/PREPAREDNESS ACTIONS...

* Travel is strongly discouraged because of dangerous conditions.

* If you must travel, keep tire chains, a flashlight, blankets, 
  food, water, medications, and a fully charged phone with you.

* The safest place during a winter storm is indoors.

* A Winter Storm Warning means that severe winter weather is
  likely and poses a threat to life and property. Take protective
  action now.

&&

$$

CAZ080-151400-
/O.UPG.KMFR.WS.A.0009.211215T1500Z-211216T0600Z/
/O.NEW.KMFR.WW.Y.0033.211215T1200Z-211216T0600Z/
/O.NEW.KMFR.WS.W.0012.211215T1200Z-211216T0600Z/
Western Siskiyou County-
Including the cities of Callahan, Etna, Fort Jones, Greenview, 
and Somes Bar
212 PM PST Tue Dec 14 2021

...WINTER STORM WARNING IN EFFECT FROM 4 AM TO 10 PM PST
WEDNESDAY...
...WINTER WEATHER ADVISORY IN EFFECT FROM 4 AM TO 10 PM PST
WEDNESDAY...

* WHAT...For the Winter Storm Warning, heavy snow expected. Total
  snow accumulations of 5 to 10 inches. Winds gusting as high as 55
  mph in exposed areas. For the Winter Weather Advisory, snow 
  expected. Total snow accumulations of 2 to 5 inches. Winds 
  gusting as high as 45 mph in exposed areas.

* WHERE...For the Warning, Greenview, Forest Mountain Summit on
  Highway 3, Etna Summit on Sawyers Bar Road. For the Advisory,
  Fort Jones, Etna.

* WHEN...From 4 AM to 10 PM PST Wednesday.

* IMPACTS...Travel could be very difficult to impossible. Blowing
  snow could significantly reduce visibility. The hazardous 
  conditions could impact the morning or evening commute. Gusty 
  winds could bring down tree branches.

* ADDITIONAL DETAILS...Snow levels will dip occasionally to near 
  the Klamath River Valley.

* View the hazard area in detail at 
  https://www.wrh.noaa.gov/map/?wfo=mfr

PRECAUTIONARY/PREPAREDNESS ACTIONS...

* Travel is strongly discouraged because of dangerous conditions.

* If you must travel, keep tire chains, a flashlight, blankets, 
  food, water, medications, and a fully charged phone with you.

* The safest place during a winter storm is indoors.

* A Winter Storm Warning means that severe winter weather is
  likely and poses a threat to life and property. Take protective
  action now.

&&

$$

CAZ081-151400-
/O.NEW.KMFR.WS.W.0012.211215T1200Z-211216T0600Z/
/O.NEW.KMFR.WW.Y.0033.211215T1200Z-211216T0600Z/
Central Siskiyou County-
Including the cities of Weed and Yreka
212 PM PST Tue Dec 14 2021

...WINTER STORM WARNING IN EFFECT FROM 4 AM TO 10 PM PST
WEDNESDAY...
...WINTER WEATHER ADVISORY IN EFFECT FROM 4 AM TO 10 PM PST
WEDNESDAY...

* WHAT...For the Winter Storm Warning, heavy snow expected. Total
  snow accumulations of 3 to 6 inches. Winds gusting as high as 60
  mph. For the Winter Weather Advisory, snow expected. Total snow
  accumulations of 1 to 3 inches. Winds gusting as high as 45 
  mph.

* WHERE...For the Warning, Interstate 5 near Weed. For the
  Advisory, Yreka, Grenada including portions of Interstate 5.

* WHEN...From 4 AM to 10 PM PST Wednesday.

* IMPACTS...Travel could be very difficult. Blowing snow could 
  significantly reduce visibility. The hazardous conditions could 
  impact the morning or evening commute. Strong winds could cause 
  tree damage.

* ADDITIONAL DETAILS...Windy conditions will likely combine with
  snow near Weed to produce very low visibility.

* View the hazard area in detail at 
  https://www.wrh.noaa.gov/map/?wfo=mfr

PRECAUTIONARY/PREPAREDNESS ACTIONS...

* Travel is strongly discouraged because of dangerous conditions.

* If you must travel, keep tire chains, a flashlight, blankets, 
  food, water, medications, and a fully charged phone with you.

* The safest place during a winter storm is indoors.

* A Winter Storm Warning means that severe winter weather is
  likely and poses a threat to life and property. Take protective
  action now.

&&

$$

CAZ082-151400-
/O.UPG.KMFR.WS.A.0009.211215T1500Z-211216T0600Z/
/O.NEW.KMFR.WS.W.0012.211215T1200Z-211216T0600Z/
South Central Siskiyou County-
Including the cities of Dunsmuir, McCloud, and Mount Shasta
212 PM PST Tue Dec 14 2021

...WINTER STORM WARNING IN EFFECT FROM 4 AM TO 10 PM PST
WEDNESDAY...

* WHAT...Heavy snow expected. Total snow accumulations of 8 to 16
  inches. Winds gusting as high as 50 mph in higher terrain and
  exposed areas.

* WHERE...South Central Siskiyou County including portions of
  Interstate 5 south of Weed and portions of Highway 89 at 
  Snowmans and Dead Horse Summit. This also includes the 
  communities of Mount Shasta City, Dunsmuir, McCloud as well as 
  rural areas east of Mount Shasta City and south of Tennant.

* WHEN...From 4 AM to 10 PM PST Wednesday.

* IMPACTS...Travel could be very difficult to impossible. Areas 
  of blowing snow could significantly reduce visibility. The 
  hazardous conditions could impact the morning or evening 
  commute. Gusty winds could bring down tree branches.

* View the hazard area in detail at 
  https://www.wrh.noaa.gov/map/?wfo=mfr

PRECAUTIONARY/PREPAREDNESS ACTIONS...

* Travel is strongly discouraged because of dangerous conditions.

* If you must travel, keep tire chains, a flashlight, blankets, 
  food, water, medications, and a fully charged phone with you.

* The safest place during a winter storm is indoors.

* A Winter Storm Warning means that severe winter weather is
  likely and poses a threat to life and property. Take protective
  action now.

&&

$$

ORZ027-028-151400-
/O.NEW.KMFR.WW.Y.0033.211215T1500Z-211216T1800Z/
South Central Oregon Cascades-
Siskiyou Mountains and Southern Oregon Cascades-
Including the cities of Crater Lake, Crescent Lake, Diamond Lake,
Union Creek, Howard Prairie, and Siskiyou Summit
212 PM PST Tue Dec 14 2021

...WINTER WEATHER ADVISORY IN EFFECT FROM 7 AM WEDNESDAY TO 10 AM
PST THURSDAY...

* WHAT...Snow expected. Total snow accumulations of 6 to 12 
  inches. Winds gusting as high as 60 mph.

* WHERE...Southern Oregon Cascades and Siskiyous including
  Interstate 5 at Siskiyou Summit, Highway 62 near Union Creek and
  Diamond Lake, Highway 138 near Diamond Lake, Highway 140 near
  Lake of the Woods, and Highway 66.  

* WHEN...From 7 AM Wednesday to 10 AM PST Thursday.

* IMPACTS...Travel could be very difficult. Blowing snow could 
  significantly reduce visibility. Strong winds could cause tree 
  damage.

* View the hazard area in detail at 
  https://www.wrh.noaa.gov/map/?wfo=mfr

PRECAUTIONARY/PREPAREDNESS ACTIONS...

* Slow down and allow extra time to reach your destination.

* Carry tire chains and be prepared for snow covered roads and 
  limited visibilities.

* See https://www.tripcheck.com or https://quickmap.dot.ca.gov 
  for latest road conditions.

* A Winter Weather Advisory for snow means that periods of snow 
  will cause travel difficulties.

&&

$$

ORZ029>031-151400-
/O.NEW.KMFR.WW.Y.0033.211215T1500Z-211216T0900Z/
Klamath Basin-
Northern and Eastern Klamath County and Western Lake County-
Central and Eastern Lake County-
Including the cities of Klamath Falls, Chemult, Crescent, 
and Valley Falls
212 PM PST Tue Dec 14 2021

...WINTER WEATHER ADVISORY IN EFFECT FROM 7 AM WEDNESDAY TO 1 AM
PST THURSDAY...

* WHAT...Snow expected. Total snow accumulations of up to 6
  inches. Winds gusting as high as 50 mph in exposed areas in
  Klamath County and up to 65 mph in high terrain areas of Lake 
  County.

* WHERE...Some areas east of the Cascades including Highway 97
  from northern portions of Klamath Falls north to Crescent,
  Highway 140 at Bly Mountain and Quartz Mountain Summit and
  Warner Mountain Summit.

* WHEN...From 7 AM Wednesday to 1 AM PST Thursday.

* IMPACTS...Plan on slippery road conditions. Blowing snow could 
  significantly reduce visibility. The hazardous conditions could 
  impact the morning or evening commute. Strong winds could cause 
  tree damage.

* ADDITIONAL DETAILS...The most significant, steady snowfall is
  expected generally from Modoc Point on Highway 97 northward.

* View the hazard area in detail at 
  https://www.wrh.noaa.gov/map/?wfo=mfr

PRECAUTIONARY/PREPAREDNESS ACTIONS...

* Slow down and allow extra time to reach your destination.

* Carry tire chains and be prepared for snow covered roads and 
  limited visibilities.

* See https://www.tripcheck.com or http://quickmap.dot.ca.gov for
  latest road conditions.

* A Winter Weather Advisory for snow means that periods of snow 
  will cause travel difficulties.

&&

$$

ORZ025-151400-
/O.NEW.KMFR.WW.Y.0033.211215T1500Z-211216T1800Z/
Eastern Douglas County Foothills-
212 PM PST Tue Dec 14 2021

...WINTER WEATHER ADVISORY IN EFFECT FROM 7 AM WEDNESDAY TO 10 AM
PST THURSDAY...

* WHAT...Wet snow expected. Total snow accumulations of 5 to 10 
  inches. Winds gusting as high as 40 mph.

* WHERE...Eastern Douglas County Foothills generally above 2000
  feet including hills surrounding Toketee Falls.

* WHEN...From 7 AM Wednesday to 10 AM PST Thursday.

* IMPACTS...Travel could be very difficult to impossible. The
  hazardous conditions could impact the morning or evening
  commute.

* View the hazard area in detail at 
  https://www.wrh.noaa.gov/map/?wfo=mfr

PRECAUTIONARY/PREPAREDNESS ACTIONS...

* Slow down and allow extra time to reach your destination.

* Carry tire chains and be prepared for snow covered roads and 
  limited visibilities.

* See https://www.tripcheck.com for latest road conditions.

* A Winter Weather Advisory for snow means that periods of snow 
  will cause travel difficulties.

&&

$$

CAZ085-151400-
/O.NEW.KMFR.WW.Y.0033.211215T1800Z-211216T0600Z/
Modoc County-
Including the cities of Day and Lookout
212 PM PST Tue Dec 14 2021

...WINTER WEATHER ADVISORY IN EFFECT FROM 10 AM TO 10 PM PST
WEDNESDAY...

* WHAT...Snow expected. Total snow accumulations of 1 to 3 inches.
  Winds gusting as high as 55 mph.

* WHERE...Portions of Modoc County including Day and Lookout.

* WHEN...From 10 AM to 10 PM PST Wednesday.

* IMPACTS...Plan on slippery road conditions. Blowing snow could 
  significantly reduce visibility. The hazardous conditions could 
  impact the evening commute. Gusty winds could bring down tree 
  branches.

* View the hazard area in detail at 
  https://www.wrh.noaa.gov/map/?wfo=mfr

PRECAUTIONARY/PREPAREDNESS ACTIONS...

* Slow down and allow extra time to reach your destination.

* Carry tire chains and be prepared for snow covered roads and 
  limited visibilities.

* See http://quickmap.dot.ca.gov for latest road conditions.

* A Winter Weather Advisory for snow means that periods of snow 
  will cause travel difficulties.

&&

$$

ORZ024-151400-
/O.NEW.KMFR.WW.Y.0033.211215T1600Z-211216T1600Z/
Eastern Curry County and Josephine County-
212 PM PST Tue Dec 14 2021

...WINTER WEATHER ADVISORY IN EFFECT FROM 8 AM WEDNESDAY TO 8 AM
PST THURSDAY ABOVE 1500 FEET...

* WHAT...Wet snow expected above 1500 feet. Total snow
  accumulations of 1 to 3 inches with 6 to 12 inches above 2500
  feet. Winds gusting as high as 55 mph in exposed areas.

* WHERE...Higher terrain of Eastern Curry County and Josephine
  County including Hayes Hill on Highway 199 and Sexton Pass on
  Interstate 5.

* WHEN...From 8 AM Wednesday to 8 AM PST Thursday.

* IMPACTS...Travel could be very difficult to impossible. 
  Widespread blowing snow could significantly reduce visibility. 
  The hazardous conditions could impact the morning or evening 
  commute. Very strong winds could cause extensive tree damage.

* ADDITIONAL DETAILS...Snow levels will likely fluctuate between
  1500 feet and 2000 feet through the Advisory period.

* View the hazard area in detail at 
  https://www.wrh.noaa.gov/map/?wfo=mfr

PRECAUTIONARY/PREPAREDNESS ACTIONS...

* Slow down and allow extra time to reach your destination.

* Carry tire chains and be prepared for snow covered roads and 
  limited visibilities.

* See https://www.tripcheck.com or http://quickmap.dot.ca.gov for
  latest road conditions.

* A Winter Weather Advisory for snow means that periods of snow 
  will cause travel difficulties.

&&

$$

ORZ023-026-151400-
/O.NEW.KMFR.WW.Y.0033.211215T1600Z-211216T1600Z/
Central Douglas County-Jackson County-
Including the city of Ashland
212 PM PST Tue Dec 14 2021

...WINTER WEATHER ADVISORY IN EFFECT FROM 8 AM WEDNESDAY TO 8 AM
PST THURSDAY ABOVE 2000 FEET...

* WHAT...Wet snow expected above 2000 feet. Total snow
  accumulations 1 to 4 inches with 4 to 8 inches above 3000 feet.
  Winds gusting as high as 45 mph in exposed areas.

* WHERE...Central Douglas County and Jackson County including
  Canyon Mountain Pass on Interstate 5, Jacksonville Hill on
  Highway 238 and hills surrounding the Rogue Valley.

* WHEN...From 8 AM Wednesday to 8 AM PST Thursday.

* IMPACTS...Travel could be very difficult. The hazardous 
  conditions could impact the morning or evening commute.

* ADDITIONAL DETAILS...Snow levels will likely fluctuate between
  2000 and 2500 feet from Wednesday into Thursday morning.

* View the hazard area in detail at 
  https://www.wrh.noaa.gov/map/?wfo=mfr

PRECAUTIONARY/PREPAREDNESS ACTIONS...

* Slow down and allow extra time to reach your destination.

* Carry tire chains and be prepared for snow covered roads and 
  limited visibilities.

* See https://www.tripcheck.com for latest road conditions.

* A Winter Weather Advisory for snow means that periods of snow 
  will cause travel difficulties.

&&

$$

Visit us at https://www.weather.gov/Medford

Area Forecast Discussion
National Weather Service Medford OR
1046 PM PST Mon Dec 13 2021

.UPDATE...

Scattered showers still cover the radar scope this evening. We
will let the winter storm warnings and advisories expire tonight
as the moisture appears to be lacking with these showers. In
addition, colder air is also filtering into the region as
temperatures are into the 30's across the area, even along the
coast. Look for a few more snow showers this evening as the
atmosphere remains disturbed and unstable.

Temperatures tonight will be tricky as clearing will result in
lows falling well into the 20's for the valleys west of the
Cascades and lower teens to single digits east of the Cascades.
However, there is potential for misty air in valleys west of the
Cascades as has been already observed in Grants Pass this
evening. We think that it won't become dense given how unstable
the air is above the boundary layer. However, patchy freezing fog
is possible given hold cold it is already and clearing aloft
should allow temperatures to converge towards valley dewpoints. As
a parting note, the NBM has roughly 90 to 100 percent chance for
lows below freezing tonight across all locations except the coast,
so if it does start to fog up, it will be freezing fog.

-Smith

&&

.SHORT TERM.../Issued 525 PM PST Mon Dec 13 2021/

A cold front lies across the forecast area this
afternoon. Ahead of it, steadier precipitation is affecting areas
from the Cascades eastward. Behind the front, a cold convective
pattern is in place, favoring additional snowfall in places like
Hayes Hill on HWY 199, Sexton Pass on I-5, and Camas Mountain on
HWY 42. The snow won't be as steady as earlier today, but
occasional bursts of snowfall will add to snow totals there. Over
the Cascades and Siskiyous, the heaviest snowfall is ongoing and
will taper off some after sunset. East of the Cascades, it's
taking a bit for rain to turn to snow in Klamath Falls but will
soon, and snow is expected through the evening. Snow will linger
in Modoc County through tonight, and the Winter (Advisory and
Warning) hazards have been extended there to reflect that.

Tonight a hazard that occurs a few times a year (at least west of
the Cascades...probably more east of the Cascades) is possible--
widespread black ice. This is because there's ample precipitation
falling this afternoon, followed by potentially clearing skies
tonight and a very cold air mass moving in. Additionally, some of
the snow where areas hovered right around freezing will melt this
afternoon and then freeze tonight. Long story short--quickly
lowering temperatures tonight could bring black ice to many areas,
including valleys west of the Cascades. Additionally, cold
temperatures at the coast (low to mid 30s) tonight will bring frost
conditions, and we've issued a Frost Advisory for that area for late
tonight into Tuesday morning.

Tuesday represents a relative break in the weather, with some snow
showers in the mountains and otherwise partly sunny skies and cool
temperatures.

On Wednesday another low pressure will send additional wind and
precipitation to the forecast area. South to north pressure
gradients will be once again impressive (about 10mb) both from
Arcata to North Bend and Redding to Medford. We've issued a High
Wind Watch for the coast for Wednesday, and Advisory type winds can
be expected in the Shasta Valley.

The front and associated precipitation will arrive Wednesday morning
at the coast and spread inland. What distinguishes this front from
today's is the cold air in place ahead of it. The air mass will much
colder than normal for this time of year, and as precipitation makes
its way into valleys west of the Cascades, some snow is expected.
For mountains, Mt Shasta City area, and areas east of the Cascades,
another significant snowfall can be expected, and we'll be issuing
new Winter Weather hazards for these areas tonight or tomorrow. What
happens in the afternoon in valleys west of the Cascades is a big
question. Will the air mass warm sufficiently to change any snow to
rain, or will the air aloft stay at or just below freezing,
maintaining snow for much of the day. The pattern is one of the main
four that can bring snow to Medford, so we do think at least a half
inch of snow will fall. We'll be anticipating high resolution model
output tonight and tomorrow morning to add confidence to our
forecast. Please stay tuned.

.LONG TERM.../Issued 525 PM PST Mon Dec 13 2021/

Thursday Through Monday...he extended forecast still looks cold,
but not particularly wet. The wettest period looks to be late
Friday night through Saturday evening.

An upper level long wave trough over the Pacific Northwest will move
out to the east Thursday night. The upstream ridge will then provide
a break in the action Thursday night into Friday. However, another
incoming short wave will break down the ridge to zonal flow, and
this wave with its associated front will move onshore Saturday with
most of the energy directed to the north of the Medford forecast
area. Precipitation will be possible as early as Friday afternoon.
Amounts will be on the light side and most of it will fall along the
coast, the Coast Range, the Umpqua Basin, and the Cascades. More
ridging will follow this wave for another relative break in the
action Sunday. It won't be totally dry, but precipitation will be
spotty and light. The ridge will break down once again Monday and a
weak trough will move onshore Monday evening. It will push a weak
front onshore ahead of it Monday.

&&

.AVIATION...14/06Z TAFs...Rain and snow showers will generally
diminish in coverage with time. Mountain obscurations are expected
across the higher terrain. A mix of MVFR and VFR conditions this
evening will likely deteriorate to IFR to even LIFR in low clouds
and fog, at times, in some sheltered inland valleys overnight into
the morning, to include KMFR and KRBG. This is already occurring at
Medford and Grants Pass. Cold overnight temperatures with water
could lead to some icy conditions on untreated runways later tonight
into Tuesday morning. After any early clouds, a mix of VFR and MVFR
is expected the rest of Tuesday. -Spilde

&&

.MARINE...Updated 920 PM PST Monday, 13 December, 2021...
Low pressure will remain in the area through Tuesday night. Steep
and hazardous seas are expected to persist tonight primarily due to
west-northwest swell and will remain elevated Tuesday through early
Wednesday morning. Isolated thunderstorms will continue to be
possible into Tuesday morning.

A very strong front is then likely to move through the waters late
Tuesday night into Wednesday. Latest hi-res guidance is indicating
sustained winds in the 35-45kt range with the potential for a
coastal jet setting up Wed morning. This could result in gusts to
60kt. We've adjusted the gale watch to a storm watch will let
overnight shift decide on potential upgrade. But, this one looks to
bring very steep winds seas (>=15ft/9sec) on top of a background WNW
swell (~6-8ft/12sec) through Wed aftn. West swell will build
Wednesday night and subside Thursday. High pressure will build
Thursday, then weaken Friday. A warm front will move through the
waters Friday. -Spilde

&&

BEACH HAZARDS...Updated 230 PM PST Tuesday, 13 December, 2021...
Wave propagation and decay tools from the offshore buoys continue to
show that High Surf Advisory conditions are likely to continue
through dark today. Wave heights also have been 2-3 feet higher than
the wave models have indicated, at times. Therefore, the High Surf
Advisory has been extended to remain in effect until 4AM PST. Long
period, high WNW swell will produce average breaking wave heights of
20 to 25 ft. These large breaking waves will create hazardous
conditions along and within the surf zone, and could inundate
beaches and low lying shorelines. Beach erosion is possible, and
exposed infrastructure could be damaged, especially at and around
the time of high tide. Jetties, rocks, and logs along the shoreline
are not the places to be during the advisory period, so stay clear
of them to remain out of harms way. ~BTL

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...Winter Storm Warning until 10 PM PST this evening for
     ORZ027-030-031.
     Winter Weather Advisory until 10 PM PST this evening for
     ORZ029-031.
     Frost Advisory from 2 AM to 8 AM PST Tuesday for ORZ021-022.
     Winter Weather Advisory until 10 PM PST this evening for ORZ028.
     Winter Storm Warning until 10 PM PST this evening above 1500
     feet in the for ORZ023>025.
     High Surf Advisory until 4 AM PST Tuesday for ORZ021-022.
     High Wind Watch from Wednesday morning through Wednesday
     afternoon for ORZ021-022.
     Winter Storm Warning until 10 PM PST this evening above 2500
     feet in the for ORZ026.
     Winter Storm Warning until 10 PM PST this evening for ORZ028.

CA...Winter Storm Warning until 10 PM PST this evening for CAZ085.
     Winter Weather Advisory until 10 PM PST this evening for
     CAZ084-085.
     Winter Storm Warning until 10 PM PST this evening for
     CAZ082-083.
     Winter Storm Warning until 10 PM PST this evening for
     CAZ080-081.

Pacific Coastal Waters...Gale Watch from late Tuesday night through Wednesday afternoon
     for PZZ350-356-370-376.
     Small Craft Advisory until 4 AM PST Wednesday for
     PZZ350-356-370-376.
     Frost Advisory from 2 AM to 8 AM PST Tuesday for PZZ350.