Winter Storm Warning 4, NWS Portland, OR

606 
WWUS46 KPQR 101758
WSWPQR

URGENT - WINTER WEATHER MESSAGE
National Weather Service Portland OR
958 AM PST Fri Dec 10 2021

WAZ019-110200-
/O.EXP.KPQR.WW.Y.0020.000000T0000Z-211210T1800Z/
/O.CON.KPQR.WS.W.0004.211211T0600Z-211212T1600Z/
South Washington Cascades-
Including the cities of Coldwater Ridge Visitors Center, 
Mount St. Helens, and Wind River Valley
958 AM PST Fri Dec 10 2021

...WINTER STORM WARNING REMAINS IN EFFECT FROM 10 PM THIS EVENING
TO 8 AM PST SUNDAY...
...WINTER WEATHER ADVISORY WILL EXPIRE AT 10 AM PST THIS
MORNING...

* WHAT...Heavy snow expected. Total snow accumulations of 18 to 30
  inches. Snow levels starting around 3000 feet Saturday morning 
  and lowering to 1500 feet Saturday night. Winds gusting as high 
  as 45 mph.

* WHERE...South Washington Cascades.

* WHEN...From 10 PM this evening to 8 AM PST Sunday.

* IMPACTS...Travel could be very difficult to impossible. Patchy 
  blowing snow could significantly reduce visibility.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If you must travel, keep an extra flashlight, food, and water in
your vehicle in case of an emergency. 

The latest road conditions for the state you are calling from can
be obtained by calling 5 1 1.

&&

$$

ORZ011-110200-
/O.EXP.KPQR.WW.Y.0020.000000T0000Z-211210T1800Z/
/O.CON.KPQR.WS.W.0004.211211T1600Z-211212T1600Z/
Northern Oregon Cascades-
Including the cities of Government Camp, Detroit, 
and Santiam Pass
958 AM PST Fri Dec 10 2021

...WINTER STORM WARNING REMAINS IN EFFECT FROM 8 AM SATURDAY TO
8 AM PST SUNDAY...
...WINTER WEATHER ADVISORY WILL EXPIRE AT 10 AM PST THIS
MORNING...

* WHAT...Heavy snow expected. Total snow accumulations of 12 to 24
  inches. Snow levels starting around 3500 feet Saturday morning 
  and lowering to 2500 feet Saturday night. Winds gusting as high 
  as 45 mph.

* WHERE...Northern Oregon Cascades.

* WHEN...From 8 AM Saturday to 8 AM PST Sunday.

* IMPACTS...Travel could be very difficult to impossible. Patchy 
  blowing snow could significantly reduce visibility. Gusty 
  winds could bring down tree branches.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If you must travel, keep an extra flashlight, food, and water in
your vehicle in case of an emergency. 

The latest road conditions for the state you are calling from can
be obtained by calling 5 1 1.

&&

$$

ORZ013-110200-
/O.CON.KPQR.WS.W.0004.211211T1600Z-211212T1600Z/
Cascades in Lane County-
Including the cities of McKenzie Pass and Willamette Pass
958 AM PST Fri Dec 10 2021

...WINTER STORM WARNING REMAINS IN EFFECT FROM 8 AM SATURDAY TO
8 AM PST SUNDAY...

* WHAT...Heavy snow expected. Total snow accumulations of 12 to 20
  inches. Snow levels starting around 3500 feet Saturday morning
  and lowering to 3000 feet Saturday night. Winds gusting as high
  as 45 mph.

* WHERE...Cascades in Lane County.

* WHEN...From 8 AM Saturday to 8 AM PST Sunday.

* IMPACTS...Travel could be very difficult to impossible. Patchy 
  blowing snow could significantly reduce visibility.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If you must travel, keep an extra flashlight, food, and water in
your vehicle in case of an emergency. 

The latest road conditions for the state you are calling from can
be obtained by calling 5 1 1.

&&

$$

507 
WWUS46 KPQR 102245
WSWPQR

URGENT - WINTER WEATHER MESSAGE
National Weather Service Portland OR
245 PM PST Fri Dec 10 2021

WAZ019-110645-
/O.CON.KPQR.WS.W.0004.211211T0600Z-211212T1600Z/
South Washington Cascades-
Including the cities of Coldwater Ridge Visitors Center and Mount
St. Helens
245 PM PST Fri Dec 10 2021

...WINTER STORM WARNING REMAINS IN EFFECT FROM 10 PM THIS EVENING
TO 8 AM PST SUNDAY...

* WHAT...Heavy snow expected. Total snow accumulations of 18 to 30
  inches. Snow levels starting around 3000 feet Saturday morning
  and lowering to 1500 feet Saturday night. Winds gusting as high
  as 45 mph.

* WHERE...South Washington Cascades.

* WHEN...From 10 PM this evening to 8 AM PST Sunday.

* IMPACTS...Travel could be very difficult to impossible. Patchy 
  blowing snow could significantly reduce visibility. Gusty 
  winds could bring down tree branches.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If you must travel, keep an extra flashlight, food, and water in
your vehicle in case of an emergency. 

The latest road conditions for the state you are calling from can
be obtained by calling 5 1 1.

&&

$$

ORZ011-110645-
/O.CON.KPQR.WS.W.0004.211211T1600Z-211212T1600Z/
Northern Oregon Cascades-
Including the cities of Government Camp and Santiam Pass
245 PM PST Fri Dec 10 2021

...WINTER STORM WARNING REMAINS IN EFFECT FROM 8 AM SATURDAY TO
8 AM PST SUNDAY...

* WHAT...Heavy snow expected. Total snow accumulations of 12 to 24
  inches. Snow levels starting around 3500 feet Saturday morning
  and lowering to 2500 feet Saturday night. Winds gusting as high
  as 45 mph.

* WHERE...Northern Oregon Cascades.

* WHEN...From 8 AM Saturday to 8 AM PST Sunday.

* IMPACTS...Travel could be very difficult to impossible. Patchy 
  blowing snow could significantly reduce visibility. Gusty 
  winds could bring down tree branches.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If you must travel, keep an extra flashlight, food, and water in
your vehicle in case of an emergency. 

The latest road conditions for the state you are calling from can
be obtained by calling 5 1 1.

&&

$$

ORZ013-110645-
/O.CON.KPQR.WS.W.0004.211211T1600Z-211212T1600Z/
Cascades in Lane County-
Including the cities of McKenzie Pass and Willamette Pass
245 PM PST Fri Dec 10 2021

...WINTER STORM WARNING REMAINS IN EFFECT FROM 8 AM SATURDAY TO
8 AM PST SUNDAY...

* WHAT...Heavy snow expected. Total snow accumulations of 12 to 
  24 inches. Snow levels starting around 3500 feet Saturday 
  morning and lowering to 2500 feet Saturday night. Winds gusting 
  as high as 45 mph.

* WHERE...Cascades in Lane County.

* WHEN...From 8 AM Saturday to 8 AM PST Sunday.

* IMPACTS...Travel could be very difficult to impossible. Patchy 
  blowing snow could significantly reduce visibility.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If you must travel, keep an extra flashlight, food, and water in
your vehicle in case of an emergency. 

The latest road conditions for the state you are calling from can
be obtained by calling 5 1 1.

&&

$$

358 
WWUS46 KPQR 110559
WSWPQR

URGENT - WINTER WEATHER MESSAGE
National Weather Service Portland OR
959 PM PST Fri Dec 10 2021

WAZ019-111400-
/O.CON.KPQR.WS.W.0004.211211T0600Z-211212T1600Z/
South Washington Cascades-
Including the cities of Coldwater Ridge Visitors Center and Mount
St. Helens
959 PM PST Fri Dec 10 2021

...WINTER STORM WARNING TONIGHT THROUGH 8 AM PST SUNDAY...

* WHAT...Heavy snow expected. Total snow accumulations of 20 to 32
  inches, with 8 to 15 inches on lower slopes between 1500 and
  2000 feet. Winds will gust 35 to 45 mph at times. 

* WHERE...South Washington Cascades.

* WHEN...Until 8 AM PST Sunday.

* IMPACTS...Travel could be very difficult at times, with near 
  white out conditions at times. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If you must travel, keep an extra flashlight, food, and water in
your vehicle in case of an emergency. 

The latest road conditions for the state you are calling from can
be obtained by calling 5 1 1.

&&

$$

ORZ011-111400-
/O.CON.KPQR.WS.W.0004.211211T1600Z-211212T1600Z/
Northern Oregon Cascades-
Including the cities of Government Camp and Santiam Pass
959 PM PST Fri Dec 10 2021

...WINTER STORM WARNING REMAINS IN EFFECT FROM 8 AM SATURDAY TO
8 AM PST SUNDAY...

* WHAT...Heavy snow expected. Total snow accumulations of 18 to 
  30 inches, with 8 to 15 inches on lower slopes between 1500 and 
  2000 feet. 

* WHERE...Northern Oregon Cascades.

* WHEN...From 8 AM Saturday to 8 AM PST Sunday.

* IMPACTS...Travel could be very difficult at times, with near 
  white out conditions at times. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If you must travel, keep an extra flashlight, food, and water in
your vehicle in case of an emergency. 

The latest road conditions for the state you are calling from can
be obtained by calling 5 1 1.

&&

$$

ORZ013-111400-
/O.CON.KPQR.WS.W.0004.211211T1600Z-211212T1600Z/
Cascades in Lane County-
Including the cities of McKenzie Pass and Willamette Pass
959 PM PST Fri Dec 10 2021

...WINTER STORM WARNING REMAINS IN EFFECT FROM 8 AM SATURDAY TO
8 AM PST SUNDAY...

* WHAT...Heavy snow expected. Total snow accumulations of 18 to 28 
  inches, with 8 to 15 inches on lower slopes between 1500 and 
  2000 feet. 

* WHERE...Cascades in Lane County.

* WHEN...From 8 AM Saturday to 8 AM PST Sunday.

* IMPACTS...Travel could be very difficult at times, with near
  white out conditions at times. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If you must travel, keep an extra flashlight, food, and water in
your vehicle in case of an emergency. 

The latest road conditions for the state you are calling from can
be obtained by calling 5 1 1.

&&

$$

654 
WWUS46 KPQR 111237
WSWPQR

URGENT - WINTER WEATHER MESSAGE
National Weather Service Portland OR
437 AM PST Sat Dec 11 2021

ORZ011-120000-
/O.EXT.KPQR.WS.W.0004.211211T1237Z-211212T1600Z/
Northern Oregon Cascades-
Including the cities of Government Camp and Santiam Pass
437 AM PST Sat Dec 11 2021

...WINTER STORM WARNING NOW IN EFFECT UNTIL 8 AM PST SUNDAY...

* WHAT...Heavy snow. Total snow accumulations of 18 to 30 inches,
  with 8 to 15 inches on lower slopes between 1500 and 2000 feet.

* WHERE...Northern Oregon Cascades.

* WHEN...Until 8 AM PST Sunday.

* IMPACTS...Travel will be very difficult. Patchy blowing snow 
  could significantly reduce visibility. Gusty winds could bring 
  down tree branches.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If you must travel, keep an extra flashlight, food, and water in
your vehicle in case of an emergency. 

The latest road conditions for the state you are calling from can
be obtained by calling 5 1 1.

&&

$$

ORZ013-120000-
/O.EXT.KPQR.WS.W.0004.211211T1237Z-211212T1600Z/
Cascades in Lane County-
Including the cities of McKenzie Pass and Willamette Pass
437 AM PST Sat Dec 11 2021

...WINTER STORM WARNING NOW IN EFFECT UNTIL 8 AM PST SUNDAY...

* WHAT...Heavy snow. Total snow accumulations of 18 to 28 inches,
  with 8 to 15 inches on lower slopes between 1500 and 2000 feet.

* WHERE...Cascades in Lane County.

* WHEN...Until 8 AM PST Sunday.

* IMPACTS...Travel will be very difficult. Patchy blowing snow 
  could significantly reduce visibility.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If you must travel, keep an extra flashlight, food, and water in
your vehicle in case of an emergency. 

The latest road conditions for the state you are calling from can
be obtained by calling 5 1 1.

&&

$$

WAZ019-120000-
/O.CON.KPQR.WS.W.0004.000000T0000Z-211212T1600Z/
South Washington Cascades-
Including the cities of Coldwater Ridge Visitors Center and Mount
St. Helens
437 AM PST Sat Dec 11 2021

...WINTER STORM WARNING REMAINS IN EFFECT UNTIL 8 AM PST SUNDAY...

* WHAT...Heavy snow. Total snow accumulations of 18 to 30 inches,
  with 8 to 15 inches on lower slopes between 1500 and 2000 feet.
  Winds will gust 35 to 45 mph at times.

* WHERE...South Washington Cascades.

* WHEN...Until 8 AM PST Sunday.

* IMPACTS...Travel will be very difficult. Patchy blowing snow 
  could significantly reduce visibility.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If you must travel, keep an extra flashlight, food, and water in
your vehicle in case of an emergency. 

The latest road conditions for the state you are calling from can
be obtained by calling 5 1 1.

&&

$$

235 
WWUS46 KPQR 112254
WSWPQR

URGENT - WINTER WEATHER MESSAGE
National Weather Service Portland OR
254 PM PST Sat Dec 11 2021

WAZ019-121400-
/O.CON.KPQR.WS.W.0004.000000T0000Z-211212T1600Z/
South Washington Cascades-
Including the cities of Coldwater Ridge Visitors Center and Mount
St. Helens
254 PM PST Sat Dec 11 2021

...WINTER STORM WARNING REMAINS IN EFFECT UNTIL 8 AM PST SUNDAY...

* WHAT...Heavy snow. Additional snow accumulations of 10 to 16
  inches, mainly above 2000 feet. Snow accumulations of 3 to 6 
  inches possible as low as 1500 feet. 

* WHERE...South Washington Cascades.

* WHEN...Until 8 AM PST Sunday.

* IMPACTS...Travel may be difficult at times, with low visibility
  at times.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If you must travel, keep an extra flashlight, food, and water in
your vehicle in case of an emergency. 

The latest road conditions for the state you are calling from can
be obtained by calling 5 1 1.

&&

$$

ORZ011-121400-
/O.CON.KPQR.WS.W.0004.000000T0000Z-211212T1600Z/
Northern Oregon Cascades-
Including the cities of Government Camp and Santiam Pass
254 PM PST Sat Dec 11 2021

...WINTER STORM WARNING REMAINS IN EFFECT UNTIL 8 AM PST SUNDAY...

* WHAT...Heavy snow. Additional snow accumulations of 10 to 18 
  inches, mainly above 2500 feet. Snow accumulations of 3 to 7 
  inches possible as low as 1500 feet. 

* WHERE...Northern Oregon Cascades.

* WHEN...Until 8 AM PST Sunday.

* IMPACTS...Travel may be difficult at times, with low visibility
  due to heavy snow.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If you must travel, keep an extra flashlight, food, and water in
your vehicle in case of an emergency. 

The latest road conditions for the state you are calling from can
be obtained by calling 5 1 1.

&&

$$

ORZ013-121400-
/O.CON.KPQR.WS.W.0004.000000T0000Z-211212T1600Z/
Cascades in Lane County-
Including the cities of McKenzie Pass and Willamette Pass
254 PM PST Sat Dec 11 2021

...WINTER STORM WARNING REMAINS IN EFFECT UNTIL 8 AM PST SUNDAY...

* WHAT...Heavy snow. Additional snow accumulations of 9 to 16
  inches, mainly above 3000 feet. Snow accumulations of 1 to 6
  inches possible as low as 2000 feet. 

* WHERE...Cascades in Lane County.

* WHEN...Until 8 AM PST Sunday.

* IMPACTS...Travel may be difficult at times, with low visibility
  due to heavy snow.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If you must travel, keep an extra flashlight, food, and water in
your vehicle in case of an emergency. 

The latest road conditions for the state you are calling from can
be obtained by calling 5 1 1.

&&

$$

ORZ003-004-WAZ020-121400-
/O.NEW.KPQR.WW.Y.0021.211212T0600Z-211213T0600Z/
Coast Range of Northwest Oregon-
Central Coast Range of Western Oregon-Willapa Hills-
254 PM PST Sat Dec 11 2021

...WINTER WEATHER ADVISORY IN EFFECT FROM 10 PM THIS EVENING TO
10 PM PST SUNDAY...

* WHAT...Snow expected. Snow level at or above 1500 feet, with
  total snow accumulations 3 to 7 inches.

* WHERE...In Washington, Willapa Hills. In Oregon, Coast Range 
  of Northwest Oregon and Central Coast Range of Western Oregon.

* WHEN...From 10 PM this evening to 10 PM PST Sunday.

* IMPACTS...Travel could be challenging at times.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Slow down and use caution while traveling. 

The latest road conditions for the state you are calling from can
be obtained by calling 5 1 1.

&&

$$

ORZ010-WAZ040-121400-
/O.NEW.KPQR.WW.Y.0021.211212T0400Z-211213T0300Z/
Northern Oregon Cascade Foothills-
South Washington Cascade Foothills-
Including the cities of Silver Falls State Park and Ariel
254 PM PST Sat Dec 11 2021

...WINTER WEATHER ADVISORY IN EFFECT FROM 8 PM THIS EVENING TO
7 PM PST SUNDAY...

* WHAT...Snow expected. Snow level 1500 to 2000 feet, with total 
  snow accumulations 3 to 7 inches.

* WHERE...In Washington, South Washington Cascade Foothills. In 
  Oregon, Northern Oregon Cascade Foothills.

* WHEN...From 8 PM this evening to 7 PM PST Sunday.

* IMPACTS...Travel could be challenging at times.


PRECAUTIONARY/PREPAREDNESS ACTIONS...

Slow down and use caution while traveling. 

The latest road conditions for the state you are calling from can
be obtained by calling 5 1 1.

&&

$$

550 
WWUS46 KPQR 121301
WSWPQR

URGENT - WINTER WEATHER MESSAGE
National Weather Service Portland OR
501 AM PST Sun Dec 12 2021

WAZ019-130000-
/O.CAN.KPQR.WS.W.0004.000000T0000Z-211212T1600Z/
/O.EXA.KPQR.WW.Y.0021.000000T0000Z-211213T0300Z/
South Washington Cascades-
Including the cities of Coldwater Ridge Visitors Center, 
Mount St. Helens, and Wind River Valley
501 AM PST Sun Dec 12 2021

...WINTER STORM WARNING HAS BEEN REPLACED WITH A WINTER WEATHER 
ADVISORY IN EFFECT UNTIL 7 PM PST THIS EVENING...

* WHAT...Snow. Additional snow accumulations of 3 to 6 inches
  above 1500 feet.

* WHERE...South Washington Cascades.

* WHEN...Until 7 PM PST this evening.

* IMPACTS...Plan on slippery road conditions.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Slow down and use caution while traveling. 

The latest road conditions for the state you are calling from can
be obtained by calling 5 1 1.

&&

$$

ORZ011-130000-
/O.CAN.KPQR.WS.W.0004.000000T0000Z-211212T1600Z/
/O.EXA.KPQR.WW.Y.0021.000000T0000Z-211213T0300Z/
Northern Oregon Cascades-
Including the cities of Government Camp, Detroit, 
and Santiam Pass
501 AM PST Sun Dec 12 2021

...WINTER STORM WARNING HAS BEEN REPLACED WITH A WINTER WEATHER 
ADVISORY IN EFFECT UNTIL 7 PM PST THIS EVENING...

* WHAT...Snow. Additional snow accumulations of 3 to 6 inches 
  above 1500 feet.

* WHERE...Northern Oregon Cascades.

* WHEN...Until 7 PM PST this evening.

* IMPACTS...Plan on slippery road conditions.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Slow down and use caution while traveling. 

The latest road conditions for the state you are calling from can
be obtained by calling 5 1 1.

&&

$$

ORZ013-130000-
/O.CAN.KPQR.WS.W.0004.000000T0000Z-211212T1600Z/
/O.EXA.KPQR.WW.Y.0021.000000T0000Z-211213T0300Z/
Cascades in Lane County-
Including the cities of McKenzie Pass, McKenzie Bridge, Oakridge,
and Willamette Pass
501 AM PST Sun Dec 12 2021

...WINTER STORM WARNING HAS BEEN REPLACED WITH A WINTER WEATHER 
ADVISORY IN EFFECT UNTIL 7 PM PST THIS EVENING...

* WHAT...Snow. Additional snow accumulations of 3 to 6 inches,
  mainly above 2500 feet.

* WHERE...Cascades in Lane County.

* WHEN...Until 7 PM PST this evening.

* IMPACTS...Plan on slippery road conditions.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Slow down and use caution while traveling. 

The latest road conditions for the state you are calling from can
be obtained by calling 5 1 1.

&&

$$

ORZ003-004-WAZ020-130000-
/O.CON.KPQR.WW.Y.0021.000000T0000Z-211213T0600Z/
Coast Range of Northwest Oregon-
Central Coast Range of Western Oregon-Willapa Hills-
501 AM PST Sun Dec 12 2021

...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 10 PM PST THIS
EVENING...

* WHAT...Snow. Snow level at or above 1500 feet, with total snow 
  accumulations 2 to 6 inches.

* WHERE...In Washington, Willapa Hills. In Oregon, Coast Range 
  of Northwest Oregon and Central Coast Range of Western Oregon.

* WHEN...Until 10 PM PST this evening.

* IMPACTS...Plan on slippery road conditions.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Slow down and use caution while traveling. 

The latest road conditions for the state you are calling from can
be obtained by calling 5 1 1.

&&

$$

ORZ010-WAZ040-130000-
/O.CON.KPQR.WW.Y.0021.000000T0000Z-211213T0300Z/
Northern Oregon Cascade Foothills-
South Washington Cascade Foothills-
Including the cities of Silver Falls State Park and Ariel
501 AM PST Sun Dec 12 2021

...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 7 PM PST THIS
EVENING...

* WHAT...Snow expected. Snow level 1500 feet, with total snow
  accumulations 2 to 5 inches.

* WHERE...In Washington, South Washington Cascade Foothills. In 
  Oregon, Northern Oregon Cascade Foothills.

* WHEN...Until 7 PM PST this evening.

* IMPACTS...Plan on slippery road conditions.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Slow down and use caution while traveling. 

The latest road conditions for the state you are calling from can
be obtained by calling 5 1 1.

&&

$$

Area Forecast Discussion...UPDATED
National Weather Service Portland OR
829 PM PST Thu Dec 9 2021

Updated Aviation and Marine Sections

.SYNOPSIS...Shower activity continues, with mostly light rain in the
lowlands and snow in the Cascades. After a relative lull on Friday,
a strong front will move through the region on Saturday accompanied
by strong southerly winds, rain, and heavy snow in the Cascades.
Cool and wet weather continues into next week.

&&

.SHORT TERM...TONIGHT THROUGH SUNDAY...RADAR imagery shows
widespread showers ongoing this afternoon as an upper level
shortwave trough is exiting east of the Cascades. With the colder
air aloft today, noted by 850 mb temperatures around -4 to -5 C,
have received reports of snow down to 700 ft today, mainly within
the more intense showers. Snow accumulation has generally remained
above 1500 ft, with reports of 6 to 8 inches in the past 12 hours in
the higher terrain of the Cascades. Expect showers to continue this
evening through tonight as a dirty ridge remains offshore. Westerly
850 mb flow and orographic effects will keep the western slopes of
the Cascades in a favorable pattern for snow showers to continue.
Ended up extending the Winter Weather Advisory through Friday
morning for the north Oregon and south Washington Cascades for an
additional amount of 4 to 8 inches expected. There also remains a
slight chance for thunder along the coast this evening, but
lightning detectors have not indicated any strikes yet today.

Shower activity should become more subdued on Friday as weak
shortwave ridging crosses the region and snow levels climb to around
3000 feet. Moist onshore flow however will maintain at least some
light precipitation chances, especially over the higher terrain. By
Friday afternoon, a warm front pushes across the northern coast
bringing more steady rain to far northwest OR and southwest WA.
Amounts expected to remain light through Friday evening.

More impactful weather will arrive late Friday night and continue
through Saturday as a strong front approaches the region. A fairly
quick moving atmospheric river will slide south along the BC coast
Friday night and drop across the Pacific NW on Saturday. GEFS and
ECMWF ensembles IVT values over 250 kg/ms are forecast, peaking just
over 500 kg/ms. Precipitable water though is expected to remain
under 1.0 inch. Multiple impacts will be associated with this
system, including possible high winds, heavy rain, and heavy
mountain snow. A warm tongue of air ahead of the front will allow
snow levels to rise to around 4000 ft along the Coast Range Saturday
morning. QPF values along the coast and western slopes of the Coast
Range around 2 to 4 inches will be possible through Sat night, while
ensembles show valley lowlands likely see around 1-2 inches of
rainfall. Snow levels along the Cascades are expected to hover
around 3000-3500 ft during the event. The current timing for the
Winter Storm Watch remains on track from early Saturday into early
Sunday morning. Snowfall accumulation is expected primarily over
3000 ft, with 1 to 2 feet of snow possible. Breezy conditions also
likely at higher terrain. A High Wind Watch has also been issued for
the coast. Models have come down somewhat from previous runs, now
showing possible wind gusts up to 60 mph from Friday evening through
Saturday morning.

A deep upper level trough will drop out of the Gulf of Alaska behind
the front Sat night and amplify offshore on Sunday. Expect snow
levels to fall again behind the front with mainly southwest flow,
which should maintain a cool and showery pattern.

&&

.LONG TERM...SUNDAY NIGHT THROUGH THURSDAY...The cool
and wet pattern will very likely continue through at least the
middle of next week as ensemble guidance shows strong agreement on
deep upper level troughing lingering over the West Coast. Therefore
maintained high PoPs across much of the area through the extended
portion of the forecast, with additional periods of mountains snow
likely during the first half of the week. Snow levels will gradually
come back down to around 1000-1500 feet through early next week as
colder air filters into the region. This may eventually yield some
greater winter weather concerns for parts of the coast range,
although the prospects for any eventual lowland snow concerns remain
more nebulous at this time. /CB

&&

.AVIATION...06Z TAFs: At 04Z radar indicated scattered shower
activity over the area associated with northwest flow aloft.
Generally VFR along the coast and interior lowlands, except for
local MVFR associated with showers. The higher terrain, such as
the Oregon Coast Range, Cascades and southwest Washington Willapa
Hills will remain frequently obscured with MVFR or worse
conditions through Friday. Will need to watch for isolated IFR or
lower conditions overnight in fog should there be any prolonged
cloud breaks. At 04Z KHIO reported MVFR vis. Should see gradually
increasing MVFR conditions developing late tonight in the
interior valleys. VFR will be the more dominant category after
18Z Fri, except for the southwest Washington coast and coastal
valleys where MVFR is most likely to occur.

For detailed regional Pac NW aviation weather
information, go online to: https://weather.gov/zse

KPDX AND APPROACHES...VFR at the terminal as of 0430Z, but cigs
were 035 to 045. Not expecting much change through 12Z, but
cannot rule out brief period of MVFR. IFR or lower conditions are
possible in the Tualatin River Valley overnight through Fri
morning. Expect mainly VFR after 18Z Fri with cigs generally
035-040. Weishaar

&&

.MARINE...Minimal changes to current forecast. Looking at
consistent conditions with seas around 11 to 13 ft at 12 seconds
through early Saturday morning. At 0430Z Fri wave heights were
generally 1-2 ft higher than guidance. Have nudged wave heights
for tonight and Fri up just a bit to account for the bias. Models
continue to advertise a very active cold front and associated
low pressure system passing to the north of the area but will
bring a southerly wind shift and an amplification of seas.
Expecting winds to quickly increase from the 15 to 20 kt with
gusts at 25 kt to around 30 to 35 kt with gusts up to 40 kt by
Saturday morning. Gale force wind gusts are possible although
models are shifting around on whether they will be widespread and
frequent or if they will be isolated. Have issued a Gale Watch
in response to those conditions.

As the southerly winds pick up, wind waves will too build. Seas
will be slightly slower to respond. Seas should build to around
16 to 18 ft at 13 to 15 seconds by late Saturday/early Sunday
morning. The GEFSWAVE Probabilistic Wave Height guidance suggests
a 40 to 60 percent chance of wave heights exceeding 18 ft Sun
afternoon through early Mon. Seas appear to reach their peak
heights around late Sunday night. May see localized waves up to
20 ft, especially in the far northern outer waters.
Weishaar/Muessle

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...High Wind Watch from Friday evening through Saturday morning
     for Central Oregon Coast-North Oregon Coast.

     Winter Weather Advisory until 10 AM PST Friday for Northern
     Oregon Cascades.

     Winter Storm Watch from Saturday morning through Sunday morning
     for Cascades in Lane County-Northern Oregon Cascades.

WA...High Wind Watch from Friday evening through Saturday morning
     for South Washington Coast.

     Winter Weather Advisory until 10 AM PST Friday for South
     Washington Cascades.

     Winter Storm Watch from Friday evening through Sunday morning
     for South Washington Cascades.

PZ...Gale Watch from Friday afternoon through Saturday afternoon for
     coastal waters from Cape Shoalwater WA to Florence OR out
     60 nm.

     Small Craft Advisory until 3 PM PST Friday for coastal waters
     from Cape Shoalwater WA to Florence OR out 60 nm.

     Small Craft Advisory until noon PST Friday for Columbia River
     Bar.

&&