February 2014 in the PNW

[HighlandExperience]

12z Canadian is pretty lame.

 

850's bottom out at just -5 for BLI.

 

That really sucks.

 

Not ready to throw the towel in until I see the EURO though.

[Parksvillewx]

Has the Canadian ever really been onboard?

 

I think it did OK with snowfall totals up here last Saturday..so 1 day before.

[TheBigOne]

Im near the northern fringe of that snowfall map, but it still looks like 5" or so for me and I would take it! Being sandwiched in the middle for the last month with south and north getting hammered, and me with a meager 1" of snow, I would defiantly take 5"! Been very odd for all of these major cold shots of air this winter and yet my area which usually does great has gotten screwed. I am still very thankful for the 4" I received in late December! Winter total is 5", lets double that this weekend!

It's been very odd period when we have cold spells as it seems snow bans are in narrow localized areas rather then widespread patterns where everybody gets a bit of something.   I wouldn't even call the snowstorms this year as *widespread* due to certain people getting favored and others getting totally shafted but whoever got it really scored!.

[bainbridgekid]

Has the Canadian ever really been onboard?

Yesterday it showed a huge snowstorm for most of Western Washington.

[Jesse]

Crazy how quickly the models fell apart on us for this one. I'm not ready to completely throw in the towel yet but this potential event is currently on life support.

 

Oh well. At least I won't have to worry about getting stranded at Long Beach under 30 inches of snow this weekend.

[TheBigOne]

My life is flashing before my eyes as I sit here and stare out at the World Trade Center... Not because I’m imagining what it would have been like to be here 13 years ago... but imagining how incredibly ******* PISSED I’m going to be if I miss out on an epic event after leaving the state during the winter months again. I have not left the PNW between December and March in 18 years since 1996.. Now I’m in NY, and look what happens. 

Has the Empire State Building and Twin Towers EVER had a snow day where they either release workers early or closed completely the next day due to heavy snow falling at the wrong timing? 

 

I know from researching the NYC public school systems often make dumb choices when conditions are questionable at best where as private schools and suburbs districts close much more easily and often spill into summer during the severest winters. 

 

Only a very few times have the NYC Public Schools ever closed in which it was whiteout conditions and the plows couldn't keep up.

[Guest Monty67]

I think it did OK with snowfall totals up here last Saturday..so 1 day before.

Yea I meant for what might be coming this weekend.

 

I thought the models, all 3, did a pretty good job with last weekends snow totals, for my area at least. Some other areas were disappointed, and others surprised.

[Weather101]

Yea I meant for what might be coming this weekend.

 

I thought the models, all 3, did a pretty good job with last weekends snow totals, for my area at least. Some other areas were disappointed, and others surprised.

Could be round 2 for us ?

 

BUT THE SITUATION BEARS WATCHING AND APPARENTLY EARLY

MODEL RUNS WERE CONSIDERABLY MORE DRAMATIC THAN THIS LATEST GUIDANCE

BUT THE PATTERN IS CERTAINLY SIMILAR TO WHAT OCCURRED THIS PAST

WEEKEND...SO THE NORTH INTERIOR COULD VERY WELL GET ANOTHER SHOT OF

WINTRY WEATHER IF THE MODELS TREND TOWARD BACK TO MORE MOISTURE.

[Parksvillewx]

Yea I meant for what might be coming this weekend.

 

I thought the models, all 3, did a pretty good job with last weekends snow totals, for my area at least. Some other areas were disappointed, and others surprised.

 

Ya, I was just taking a stab @ the Canadian for showing something 1 DAY before. 

 

I think the WRF did the best for my location.  Other places like Nanaimo received way more snow then any models were showing. 

 

What did your total @ Shawnigan end up being? Can't remember what you said....

[catnip]

Well hello there......

[MR.SNOWMIZER]

The way the arctic high pushes south and west its hard to believe the outcome will be what current models are showing. Still about 12 model runs to go on the gfs before we know.

[Jesse]

12z ensembles keep hope alive.

[MossMan]

Well hello there......

WOW! What would make the operational that far apart from the mean? Almost every ensemble is colder than the operational.

 

Can't wait for the Euro!

[Phil]

Sorry to sound like a troll...but the Euro sucks. Cascades keep the cold air out..850s bottom at -4 for SEA.

[BLI snowman]

12z Euro is okay, similar to 00z so far but with a much more obvious snowmaker on Saturday.

[BLI snowman]

The Euro sucks. Cascades keep the cold air out..850s bottom at -4 for SEA.

 

It would bring a brief event for Seattle south, then a more prolonged event up here.

 

Still punches the westerlies in by Monday.

[epiceast]

euro snowfall maps?

[Phil]

It would bring a brief event for Seattle south, then a more prolonged event up here.

 

Still punches the westerlies in by Monday.

There is a warm-nose progged @ ~925mb.

 

Not sure I believe that though since I can't figure out why it's there. That's something more typical of WAA, and there's not much of that. Good news is the thermals above 800mb favor good dendrite growth..so if the warm nose is an error then it should be a good ratio snow.

[Guest Monty67]

Ya, I was just taking a stab @ the Canadian for showing something 1 DAY before. 

 

I think the WRF did the best for my location.  Other places like Nanaimo received way more snow then any models were showing. 

 

What did your total @ Shawnigan end up being? Can't remember what you said....

Sat - 7"

Sun - 6"

Mon - 5.5"

 

Max snow depth was 14". A lot of compaction and melting as temps were between 30-35F for the entire event.

[Snowman5678]

East winds drying up the foothills very evident...a dusting at best for me if this were to verify...Drying east winds will be an issue if the cold air in general verifies

[MR.SNOWMIZER]

There is a warm-nose progged @ ~925mb.

 

Not sure I believe that though since I can't figure out why it's there. That's something more typical of WAA, and there's not much of that. Good news is the thermals above 800mb favor good dendrite growth..so if the warm nose is an error then it should be a good ratio snow.

Can you explain dendrite growth please.

[bainbridgekid]

It would bring a brief event for Seattle south, then a more prolonged event up here.

 

Still punches the westerlies in by Monday.

Interesting to see the cold quickly return for Washington Monday night though on the Euro

 

-8 850's for SEA and -10 for BLI after rising briefly above zero during the day Monday.

 

Still an outlier in that respect though so not buying it.

[Parksvillewx]

Hopefully the Arctic front will be quite strong. I usually do quite well with some sea effect snow in those situations...at least in other winters.

[HighlandExperience]

East winds drying up the foothills very evident...a dusting at best for me if this were to verify...Drying east winds will be an issue if the cold air in general verifies

 

I don't like that, but it is the WRF and I take it with a grain of salt.

[Phil]

Can you explain dendrite growth please.

http://img836.imageshack.us/img836/2960/928x.jpg

 

 

Yokoyama/Kuroda et al:

 

http://journals.aps.org/pra/abstract/10.1103/PhysRevA.41.2038

 

 

If you want to go above and beyond current limitations, there appears to be an electrodynamic component as well: http://www.its.caltech.edu/~atomic/snowcrystals/electric/electric.htm

[BLI snowman]

There is a warm-nose progged @ ~925mb.

 

Not sure I believe that though since I can't figure out why it's there. That's something more typical of WAA, and there's not much of that. Good news is the thermals above 800mb favor good dendrite growth..so if the warm nose is an error then it should be a good ratio snow.

 

I agree. It looks like snow to me, given the surface dynamics.

[IbrChris]

K-Mart getting some publicity, from Daily Kos no less.

http://www.dailykos.com/story/2014/02/25/1280276/-Rumors-of-a-historic-winter-storm-next-week-are-a-HOAX-Spread-the-word

[Phil]

Analyzing the ECMWF/GGEM, I think the problem is they keep the PV too far west, holding it up in western Canada, perturbing the meridional stress. The GFS meanwhile pushes it further SE, allowing the cold farther south.

 

If the PV remains in western Canada, the cold will struggle to make it past the Cascades. In January we can get away with that, but if I lived in SEA I'd want the GFS to verify.

[IbrChris]

 

 

Yokoyama/Kuroda et al:

 

http://journals.aps.org/pra/abstract/10.1103/PhysRevA.41.2038

 

 

If you want to go above and beyond current limitations, there appears to be an electrodynamic component as well: http://www.its.caltech.edu/~atomic/snowcrystals/electric/electric.htm

 

Temperature is one component, supersaturation w.r.t. ice is another. Temperature is a big factor mostly in the number of ice nuclei available as certain particles work as ice nuclei at certain temperatures. At -40 degrees any particle in the air becomes an ice nuclei meaning there's no supercooled water droplets at -40 Celsius or colder. When a cloud glaciates it's usually in response to cloud top temperatures getting fairly close to -40 or at least cold enough that most particles in the air are ice crystal nuclei. This then creates a feedback reaction via the Bergeron-Findeisen process by which some supercooled droplets turn into ice crystals at the expense of other supercooled droplets due to the supersaturation w.r.t. ice being lower than w.r.t. liquid water. Thus your pop-up cold pool Cb quickly glaciates from the top down to near the freezing level.

[Snowman5678]

I don't like that, but it is the WRF and I take it with a grain of salt.

Well with this setup we are going to see east winds and east winds usually dry out the eastside...idk we'll see.

[epiceast]

Can you explain dendrite growth please.

Snow formed between -15C and -20C is the "best"(driest) and produces the highest snow to water ratio(20~~25:1). Usually you want to look at 700mb temps for this.

[IbrChris]

Snow formed between -15C and -20C is the "best"(driest) and produces the highest snow to water ratio(20~~25:1). Usually you want to look at 700mb temps for this.

 

I've seen 40:1 ratios in the Utah mountains. Generally a dry snow is around 20:1 though. Climatological ratios for mid-elevation in the Cascades are around 14:1.

[epiceast]

K-Mart getting some publicity, from Daily Kos no less.

 

http://www.dailykos.com/story/2014/02/25/1280276/-Rumors-of-a-historic-winter-storm-next-week-are-a-HOAX-Spread-the-word

Too bad they didnt say anything about his maps.

[MR.SNOWMIZER]

Temperature is one component, supersaturation w.r.t. ice is another. Temperature is a big factor mostly in the number of ice nuclei available as certain particles work as ice nuclei at certain temperatures. At -40 degrees any particle in the air becomes an ice nuclei meaning there's no supercooled water droplets at -40 Celsius or colder. When a cloud glaciates it's usually in response to cloud top temperatures getting fairly close to -40 or at least cold enough that most particles in the air are ice crystal nuclei. This then creates a feedback reaction via the Bergeron-Findeisen process by which some supercooled droplets turn into ice crystals at the expense of other supercooled droplets due to the supersaturation w.r.t. ice being lower than w.r.t. liquid water. Thus your pop-up cold pool Cb quickly glaciates from the top down to near the freezing level.

You and phil are some real weather geeks. I love it. Awesome description from both of you guys!

[IbrChris]

Problem is, the 06z was pretty bad too.

So we should just stick a fork in winter. I seem to recall someone doing that a couple weeks ago.

[luvssnow_spokane]

Analyzing the ECMWF/GGEM, I think the problem is they keep the PV too far west, holding it up in western Canada, perturbing the meridional stress. The GFS meanwhile pushes it further SE, allowing the cold farther south.

 

If the PV remains in western Canada, the cold will struggle to make it past the Cascades. In January we can get away with that, but if I lived in SEA I'd want the GFS to verify.

I feel that this may not play out very well for us. 

[IbrChris]

You and phil are some real weather geeks. I love it. Awesome description from both of you guys!

I'd have to go back to my cloud physics lecture notes to go into any further detail...have them in a box somewhere. I really enjoyed that class.

[TT-SEA]

Home sweet home.   And a great day to return.   Bright and sunny here... got the mail just now barefoot and it did not feel cold.      

 

Landing in Seattle this morning:

http://s18.postimg.org/se5rmt8jd/1596912_603604143041131_131460570_o.jpg

[IbrChris]

You and phil are some real weather geeks. I love it. Awesome description from both of you guys!

There's also some latent heat released in condensation but I don't believe a phase change from a supercooled droplet to an ice crystal produces a similar effect. If it did glaciation should help strengthen updrafts when in reality it generally corresponds to a weakening of updrafts and a more downdraft/precip dominated cell. Whether it's a cause of weakening updrafts or just happens to coincide with them due to the storm being in the mature to initial dissipation stage I'm not sure of. 

[Timmy Supercell]

12z is a let down.

 

Of course. Ya all gotta start looking for the TRENDS not the outlier or drunk or high on crack single runs on a model!!!