March 2017 Observations and Model Discussion for the Pacific Northwest

[TT-SEA]

A skiff of snow overnight... but the real story is the sun!    

 

[Bryant]

Nice! Ended up with just over 1" here. Seems like your location is starting to perform a little more to your liking.

Yeah, it was a rough start, but now I know a little more of what to expect given the type of situation. Weak outflow dependant events won't deliver here, where as they might dump on Bellingham. When the upper levels are cold however, the elevation here helps a lot.

 

Would be nice if Bellingham and locations to the south were getting snow, always nice when places around you score as well.

[snow_wizard]

You mind posting the wxbell map?

 

The first one is through day 10 and the second through day 16.  Crazy s**t!

[snow_wizard]

Yup, right now the GFS is on its own with a semi- historic pattern. Would be nice for the other models to jump on board.

 

The ECMWF ensemble has been slowly moving toward the GFS.  The GFS progression is perfectly reasonable...especially given the precedent this winter.

[Jesse]

The ECMWF ensemble has been slowly moving toward the GFS. The GFS progression is perfectly reasonable...especially given the precedent this winter.

I will give you that. We have definitely grown accustomed to things taking the colder path this winter. And this wouldn't be the first time the Euro had given in to the GFS in regard to cold.

[Front Ranger]

Funny, Seattle NWS was talking yesterday about the sun going away until further notice.

 

[Deweydog]

Funny, Seattle NWS was talking yesterday about the sun going away until further notice.

 

Screenshot_1.png

That photograph seems to be contradictory!!!

[Front Ranger]

That photograph seems to be contradictory!!!

 

Pics don't lie!

[van city]

Pics don't lie!

Fake.

[Front Ranger]

Great discussion by jaya this morning.

 

.SHORT TERM...An expansive cold 517 DAM 500-mb low centered near
48N 131W is producing widespread showers offshore. The air mass
associated with this upper level feature is quite cold and
unstable aloft with 500 mb temperatures around -40C at its core. A
few lightning strikes are being seen offshore with the higher
topped cells.

The cold air mass moved into Western Washington late last night.
Showers with a convergence zone from about Port Townsend northeast
across Whidbey Island into Anacortes, Burlington and areas to the
east and north of Mount Vernon all had some wet snow. DOT web cams
show an area with snow covering the ground and a spotter east of
I-5 in Skagit county reported 2 inches overnight. This area of
convergence continues to produce wet snow, but no additional
accumulations are expected today as daytime heating lifts the snow
levels a bit.

The next area of interest is an instant occlusion or deformation
band that is wrapping around the offshore low, now over the
offshore waters. This band is expected to spread onto the coast
late this afternoon or early this evening, then into the interior
later tonight. By early Sunday morning, this band will push
northward into the north interior zones and weaken. Latest GFS and
NAM solutions show temperatures too warm this afternoon for
lowland snow along the central coast and through the Chehalis Gap.
But later this evening, temperatures will fall and snow levels
will drop to 200-400 feet and will give snow showers, mainly to
hills, from Seattle and Bellevue west across the Kitsap Peninsula
and onto the north coast. This band of more organized snow showers
will then lift northward across the Everett area and Admiralty
Inlet on its way into the north interior. Hilltops will see up to
2 inches of snow by Sunday morning, and the northern interior
zones from Mount Vernon or so northward to the Canadian border
could see a bit more. Will look at possibly issuing a winter
weather advisory later tonight into Sunday morning for areas north
of a Seattle to 20 miles north of Hoquiam line in the lowland for
1-3 inches of snow, with most accumulations away from major bodies
of water and on hills above 300 feet or so.

Any snow that falls in the lowlands Sunday morning will quickly
melt away in warm March sunshine. High temperatures will be in the
lower 40s on Sunday.

The upper low moves across the area Sunday night and Monday
morning. The GFS, and to a greater degree the NAM12, show the
development of an area of convergence from north of Seattle to
Everett and Arlington in the interior westward to the northern
Olympic Peninsula during this period. Some areas on hilltops above
a couple hundred feet could see accumulating snow with this
convergence zone, and accumulations could be locally significant
if the convergence zone stalls in one location. At this time it is
too early to nail anything down with this feature.

Finally late Monday night and Tuesday another more organized low
moves across southern portions of Washington or northern Oregon.
Could we get more widespread snow with this feature? The incoming
GFS shows the potential for a couple of inches from about Seattle
northward early Tuesday as the low moves by to the south. Low
level thicknesses and 925 mb temperatures shown by the 12Z model
solutions are colder than previous runs. Again, it is too early to
say how things will play out with this feature, but it will be one
to watch closely. Albrecht

[SilverFallsAndrew]

Sunny here too... Time to celebrate sunshine in this land of constant troughs!

[snow_wizard]

Great discussion by jaya this morning.

 

.SHORT TERM...An expansive cold 517 DAM 500-mb low centered near

48N 131W is producing widespread showers offshore. The air mass

associated with this upper level feature is quite cold and

unstable aloft with 500 mb temperatures around -40C at its core. A

few lightning strikes are being seen offshore with the higher

topped cells.

 

The cold air mass moved into Western Washington late last night.

Showers with a convergence zone from about Port Townsend northeast

across Whidbey Island into Anacortes, Burlington and areas to the

east and north of Mount Vernon all had some wet snow. DOT web cams

show an area with snow covering the ground and a spotter east of

I-5 in Skagit county reported 2 inches overnight. This area of

convergence continues to produce wet snow, but no additional

accumulations are expected today as daytime heating lifts the snow

levels a bit.

 

The next area of interest is an instant occlusion or deformation

band that is wrapping around the offshore low, now over the

offshore waters. This band is expected to spread onto the coast

late this afternoon or early this evening, then into the interior

later tonight. By early Sunday morning, this band will push

northward into the north interior zones and weaken. Latest GFS and

NAM solutions show temperatures too warm this afternoon for

lowland snow along the central coast and through the Chehalis Gap.

But later this evening, temperatures will fall and snow levels

will drop to 200-400 feet and will give snow showers, mainly to

hills, from Seattle and Bellevue west across the Kitsap Peninsula

and onto the north coast. This band of more organized snow showers

will then lift northward across the Everett area and Admiralty

Inlet on its way into the north interior. Hilltops will see up to

2 inches of snow by Sunday morning, and the northern interior

zones from Mount Vernon or so northward to the Canadian border

could see a bit more. Will look at possibly issuing a winter

weather advisory later tonight into Sunday morning for areas north

of a Seattle to 20 miles north of Hoquiam line in the lowland for

1-3 inches of snow, with most accumulations away from major bodies

of water and on hills above 300 feet or so.

 

Any snow that falls in the lowlands Sunday morning will quickly

melt away in warm March sunshine. High temperatures will be in the

lower 40s on Sunday.

 

The upper low moves across the area Sunday night and Monday

morning. The GFS, and to a greater degree the NAM12, show the

development of an area of convergence from north of Seattle to

Everett and Arlington in the interior westward to the northern

Olympic Peninsula during this period. Some areas on hilltops above

a couple hundred feet could see accumulating snow with this

convergence zone, and accumulations could be locally significant

if the convergence zone stalls in one location. At this time it is

too early to nail anything down with this feature.

 

Finally late Monday night and Tuesday another more organized low

moves across southern portions of Washington or northern Oregon.

Could we get more widespread snow with this feature? The incoming

GFS shows the potential for a couple of inches from about Seattle

northward early Tuesday as the low moves by to the south. Low

level thicknesses and 925 mb temperatures shown by the 12Z model

solutions are colder than previous runs. Again, it is too early to

say how things will play out with this feature, but it will be one

to watch closely. Albrecht

Many chances for sure. I think he might be emphasizing north of Seattle too much though. Most models show plenty south of Seattle also.

[snow_wizard]

Funny, Seattle NWS was talking yesterday about the sun going away until further notice.

 

Screenshot_1.png

OMG sun! We've never seen that before.

[SilverFallsAndrew]

There are 2 ensemble camps. One that really starts cooling things off by the end of next week, the other delays the cool down a couple days.

[MossMan]

Great discussion by jaya this morning.

 

.SHORT TERM...An expansive cold 517 DAM 500-mb low centered near

48N 131W is producing widespread showers offshore. The air mass

associated with this upper level feature is quite cold and

unstable aloft with 500 mb temperatures around -40C at its core. A

few lightning strikes are being seen offshore with the higher

topped cells.

 

The cold air mass moved into Western Washington late last night.

Showers with a convergence zone from about Port Townsend northeast

across Whidbey Island into Anacortes, Burlington and areas to the

east and north of Mount Vernon all had some wet snow. DOT web cams

show an area with snow covering the ground and a spotter east of

I-5 in Skagit county reported 2 inches overnight. This area of

convergence continues to produce wet snow, but no additional

accumulations are expected today as daytime heating lifts the snow

levels a bit.

 

The next area of interest is an instant occlusion or deformation

band that is wrapping around the offshore low, now over the

offshore waters. This band is expected to spread onto the coast

late this afternoon or early this evening, then into the interior

later tonight. By early Sunday morning, this band will push

northward into the north interior zones and weaken. Latest GFS and

NAM solutions show temperatures too warm this afternoon for

lowland snow along the central coast and through the Chehalis Gap.

But later this evening, temperatures will fall and snow levels

will drop to 200-400 feet and will give snow showers, mainly to

hills, from Seattle and Bellevue west across the Kitsap Peninsula

and onto the north coast. This band of more organized snow showers

will then lift northward across the Everett area and Admiralty

Inlet on its way into the north interior. Hilltops will see up to

2 inches of snow by Sunday morning, and the northern interior

zones from Mount Vernon or so northward to the Canadian border

could see a bit more. Will look at possibly issuing a winter

weather advisory later tonight into Sunday morning for areas north

of a Seattle to 20 miles north of Hoquiam line in the lowland for

1-3 inches of snow, with most accumulations away from major bodies

of water and on hills above 300 feet or so.

 

Any snow that falls in the lowlands Sunday morning will quickly

melt away in warm March sunshine. High temperatures will be in the

lower 40s on Sunday.

 

The upper low moves across the area Sunday night and Monday

morning. The GFS, and to a greater degree the NAM12, show the

development of an area of convergence from north of Seattle to

Everett and Arlington in the interior westward to the northern

Olympic Peninsula during this period. Some areas on hilltops above

a couple hundred feet could see accumulating snow with this

convergence zone, and accumulations could be locally significant

if the convergence zone stalls in one location. At this time it is

too early to nail anything down with this feature.

 

Finally late Monday night and Tuesday another more organized low

moves across southern portions of Washington or northern Oregon.

Could we get more widespread snow with this feature? The incoming

GFS shows the potential for a couple of inches from about Seattle

northward early Tuesday as the low moves by to the south. Low

level thicknesses and 925 mb temperatures shown by the 12Z model

solutions are colder than previous runs. Again, it is too early to

say how things will play out with this feature, but it will be one

to watch closely. Albrecht

Thanks for the great writeup Jaya!

[Perturbed Member]

The WRF doesn't have much credibility for me this winter but a final event like this in PDX Sunday night would be great. 

 

 

http://www.atmos.washington.edu/wrfrt/data/2017030412/images_d3/or_snow72.84.0000.gif

[epiceast]

The WRF doesn't have much credibility for me this winter but a final event like this in PDX Sunday night would be great. 

 

 

http://www.atmos.washington.edu/wrfrt/data/2017030412/images_d3/or_snow72.84.0000.gif

Yea that would be a 2 foot winter for part of the metro. Would go down in the books for sure.

[SilverFallsAndrew]

The WRF doesn't have much credibility for me this winter but a final event like this in PDX Sunday night would be great. 

 

 

http://www.atmos.washington.edu/wrfrt/data/2017030412/images_d3/or_snow72.84.0000.gif

 

D**n, WRF not backing down. This would be 6-10" for the S. Salem hills. 

[Jesse]

Hopefully the 12z Euro blinks!

[epiceast]

Hopefully the 12z Euro blinks!

The right way too...

[VancouverIslandSouth]

Hopefully the 12z Euro blinks!

 

Does this count?

 

http://www.tropicaltidbits.com/analysis/models/ecmwf/2017030412/ecmwf_T850_nwus_8.png

[epiceast]

Does this count?

 

http://www.tropicaltidbits.com/analysis/models/ecmwf/2017030412/ecmwf_T850_nwus_8.png

Only Snowfall maps count

[FroYoBro]

42 degrees and moderate rain.

 

Ahhh the start of spring! 

[SilverFallsAndrew]

Does this count?

 

http://www.tropicaltidbits.com/analysis/models/ecmwf/2017030412/ecmwf_T850_nwus_8.png

Looks like a step in the right direction.

[SilverFallsAndrew]

[FroYoBro]

Euro

 

Wow. It's official. 

[VancouverIslandSouth]

The ECMWF is now showing a colder solution than the GFS. It's showing what would be the coldest upper level airmass of the season so far if it were to verify.

 

Meanwhile, it's partly cloudy here now with the offshore flow starting up. Tonight will be interesting but there's a good chance the deformation starts breaking apart as it makes its way north.

[epiceast]

Euro

https://www.youtube.com/watch?v=t2V0iNzIgjI

 

We need to get DJ Khaled to say Euro Alert on his snapchat!

[FroYoBro]

https://www.youtube.com/watch?v=t2V0iNzIgjI

 

We need to get DJ Khaled to say Euro Alert on his snapchat!

Major Euro alert. 

[HighlandExperience]

[VancouverIslandSouth]

Yeah, it was a rough start, but now I know a little more of what to expect given the type of situation. Weak outflow dependant events won't deliver here, where as they might dump on Bellingham. When the upper levels are cold however, the elevation here helps a lot.

 

Would be nice if Bellingham and locations to the south were getting snow, always nice when places around you score as well.

 

I figured your area would start to do well in a cold onshore flow pattern like this, it's probably pretty ideal for cold air damming over there and the elevation fends of low level warmth from the Strait/enhances precipitation. We need it much cooler at the upper levels for something more widespread, we still haven't experienced what I would consider an Arctic upper level airmass (the sort we saw in Nov 2006 for instance).

[Fircrest]

Many chances for sure. I think he might be emphasizing north of Seattle too much though. Most models show plenty south of Seattle also.

I hope your are right.  I would sure like to pad my anemic snowfall totals for the winter so far.  It is sure amazing how the switch did flip to cold once December started.  Definitely fun to be following snow chances in March, though I know many people are ready for spring. Just not me yet!

[GHweatherChris]

I just need a bit over an inch of snow to get to 10 inches, we had a trace this morning. Still though, this winter in my opinion has been kind of blah overall.

[MR.SNOWMIZER]

I just need a bit over an inch of snow to get to 10 inches, we had a trace this morning. Still though, this winter in my opinion has been kind of blah overall.

It's been very cold on average but I have only had 25 inches of snow and in 2008 56 and 2007 had 49.

[HighlandExperience]

It's been very cold on average but I have only had 25 inches of snow and in 2008 56 and 2007 had 49.

 

for how cold this winter has been, sure has underperformed in snow totals.

[Brennan]

It's too bad we didn't enter this pattern in January.... snow day and night and day and night minus the melting in between

[MossMan]

It's too bad we didn't enter this pattern in January.... snow day and night and day and night minus the melting in between

We can always count on March...too bad we can't buy a snowflake in January!

[Jesse]

for how cold this winter has been, sure has underperformed in snow totals.

There have been many similarly cold winters with moderate snow totals, historically.

 

Cold doesn't always guarantee snow.

[HighlandExperience]

There have been many similarly cold winters with moderate snow totals, historically.

 

Cold doesn't always guarantee snow.

 

Yup I agree. Would be awesome if every winter was like this with multiple chances for snow... 

[Jesse]

Yup I agree. Would be awesome if every winter was like this with multiple chances for snow...

Agreed. It's been really enjoyable. Crazy to think this was probably a close to average winter around here in 1850.