Colorado Weather Discussion Thread

**Rontele** · 12-08-2009, 10:06 PM

Originally Posted by gratzo

You got it. WSW through NW sounds about right, and you should know since you live there! On slide #22, I show favored wind directions, with the WSW arrow pointed to Aspen. I should probably add W to NW on there, too.

Quick WEATHER GEEK note: Rontele and I were talking yesterday about orographics vs. dynamics leading to more snow. We get snow when moist air goes up (the air cools and moisture condenses into snow). Air can go up either because physics says it should (due to a storm "lifting" the air...dynamics) or because air runs into a mountain and it is forced up (orographics). A quick calculation yesterday showed that the strongest dynamics get air going up at maybe 0.5-1.0mph (super strong dynamics) while orographics can get air going up about 10x faster (8-10mph). The gist is that dynamics are a big deal, but orographics can either enhance or retard snowfall up to 10x better than dynamics.

Most of the computer weather models operate on scales that don't take into account the mountains in enough detail to fully capture the orographic effect.

Thanks for listening...

Would you say that the heavy snow in the Colorado river valley (Eagle, Glenwood, etc.) is dynamically drive or orographically driven and since there is a lack of mountains in that area, did dynamics have a greater impact?

**MakersTeleMark** · 12-09-2009, 12:30 AM

Originally Posted by gratzo

...orographics can either enhance or retard snowfall up to 10x better than dynamics...

It's all about the oral. And you said retard, not me. Nice to see the site development from last year, btw. Let me know if you want to make some turns around ege.

**gratzo** · 12-09-2009, 01:05 AM

Originally Posted by Rontele

Would you say that the heavy snow in the Colorado river valley (Eagle, Glenwood, etc.) is dynamically drive or orographically driven and since there is a lack of mountains in that area, did dynamics have a greater impact?

Yep, dynamics were just as good over Eagle and Glenwood as they were 30 miles to the east over BC and Vail. However, SW flow doesn't downslope as much upstream from Eagle and Glenwood (down from 11k), but it downslopes a bunch upstream of BC and Vail from the Elks, New York Mtn area and Holy Cross Mtn area (down from 14k). The extra 3,000ft of downslope can likely dry the air just enough to keep BC and Vail in the dark.

This is also probably why Douglas Pass and Powderhorn - west of Eagle - also did well, because the dynamics were equally as good and the orographics were neutral rather than a hindrance. Obviously, the atmosphere is not a simple thing, but this is my simple explanation because I can't think of anything else that would cause BC and Vail to consistently get robbed of that much snow in SW flow.

**PowTron** · 12-09-2009, 06:46 AM

Well, these Vail and Beav depth totals are really a bummer this morning...back to bed for me

**Rontele** · 12-09-2009, 07:31 AM

active pattern looks to continue into this weekend with the south and central mountains favored early on (saturday time frame) before the flow switches over to the NW (sunday-monday)...

**LaBelle23** · 12-09-2009, 10:29 AM

Originally Posted by concretejungle

Anyone been up to the IPW (west of Allenspark area) lately? There's enough snow at the house that I think it might be decent.

Winds have started up today around the IPW -- lots of wind transport has already happened. Feels like gusts to 50, and I'm a few miles east of IP. 6 inches reported at eldora over the last 24 hrs. The sun is out for the first time since Saturday too.

**stupendous man** · 12-09-2009, 10:34 AM

9 inches in Vail could mean a foot up high!

**Rontele** · 12-09-2009, 10:36 AM

Originally Posted by stupendous man

9 inches in Vail could mean a foot up high!

agreed. 123

**gratzo** · 12-09-2009, 12:51 PM

I would love to hit up IPW west of Allenspark, but some friends were in RMNP this past weekend and said it was really, REALLY thin. This leads me to think that IPW might be the same way. Not a ton of snow from this last storm, even though the ground is white and the sun is out.

Big times winds still raking the northern front range (40mph, gusts to 60mph) up above 10-11k. Slightly less back toward Summit and Eagle counties (10-20mph, gusts to 30mph).

Agreed with Rontele - weak storm Fri night into Sat (favoring south/central), and better storm Sat night through Sunday, favoring south/central then shifting to northern mountains by later Sunday. Might get clipped by a few weak storms from the NNW next week before a dry ridge builds in for next weekend. After that, looks like a ridge in the west and a trough in the east, but the trough could be large enough to keep Colorado cold and with some light snow, at least across the north and eastern areas.

**PowTron** · 12-09-2009, 01:29 PM

Originally Posted by Rontele

agreed. 123

I agree as well, but there is not a lot open and 9 inches on top of Rock and Grass isn't too appetizing for me

.

If this holds as you are saying, though, going back to the NW flow may mean some nice turns next Monday and/or Tuesday.

**Rontele** · 12-09-2009, 01:37 PM

Originally Posted by gratzo

I would love to hit up IPW west of Allenspark, but some friends were in RMNP this past weekend and said it was really, REALLY thin. This leads me to think that IPW might be the same way. Not a ton of snow from this last storm, even though the ground is white and the sun is out.

Big times winds still raking the northern front range (40mph, gusts to 60mph) up above 10-11k. Slightly less back toward Summit and Eagle counties (10-20mph, gusts to 30mph).

Agreed with Rontele - weak storm Fri night into Sat (favoring south/central), and better storm Sat night through Sunday, favoring south/central then shifting to northern mountains by later Sunday. Might get clipped by a few weak storms from the NNW next week before a dry ridge builds in for next weekend. After that, looks like a ridge in the west and a trough in the east, but the trough could be large enough to keep Colorado cold and with some light snow, at least across the north and eastern areas.

This wave still on track to come through this afternoon? Cams show partly cloudy skies with things starting to fill in over the Gore.

**PowTrees** · 12-09-2009, 02:33 PM

Originally Posted by Rontele

This wave still on track to come through this afternoon? Cams show partly cloudy skies with things starting to fill in over the Gore.

There were clouds over the high peaks of the Gore visible from Vail today. Looked like it was snowing up above Piney and on some of those high peaks most of the morning. The sky above Eagle/Vail is cloudy right now and the wind seems to have picked up a little. Was cold this morning.

Early this morning there was a Yellowjacket with a sign saying chair 11 won't open today. Did chair 11 start later or anything other than Game Creek open today?? The fresh snow in Game Creek was good, but a little wind affected. Trees were beyond dangerous, but there's some nice snow around in there...

**montanaskier** · 12-09-2009, 02:48 PM

11 should spin tomorrow. Woke up to bluebird and cold. Clouds on the build and the wind as well. Still looks like an extra 2-4" by in the morning. Hope Sunday pans out. With another ridge next week it might be a few days before we have another shot at a big storm. This area really needs a good cycle to start.

edit: wind screaming now in western Eagle County, I mean screaming.

**MakersTeleMark** · 12-09-2009, 03:56 PM

Talked to a patroller who stated that they were having problems with an ice layer down low in the pack. Still bombing the shit out of upper snag. Who knows about 11, but it was really fun to be out there today. Found some pockets of telekneedeep, but pretty much a charging chowder fest. Time to cold wax.

**Gregger** · 12-09-2009, 03:59 PM

A few late week disturbances, and a possibly stronger one for Sunday/Monday could make for some fun.

**funkendrenchman** · 12-09-2009, 04:24 PM

Be careful out there... the snowpack is VERY reactive right now!

**PowTrees** · 12-09-2009, 04:59 PM

Originally Posted by MakersTeleMark

Talked to a patroller who stated that they were having problems with an ice layer down low in the pack. Still bombing the shit out of upper snag. Who knows about 11, but it was really fun to be out there today. Found some pockets of telekneedeep, but pretty much a charging chowder fest. Time to cold wax.

I had to wonder also, with the economy, if Vail isn't really in a hurry to open more lifts to service marginal snow conditions?

**MakersTeleMark** · 12-09-2009, 05:24 PM

Vail never has marginal snow conditions.

**montanaskier** · 12-09-2009, 05:25 PM

I should go hit upper snag, I need a pass for next year

**MakersTeleMark** · 12-09-2009, 05:44 PM

Originally Posted by montanaskier

I should go hit upper snag, I need a pass for next year

Too many trees. You need to try and get Genghis to rip.

**Rontele** · 12-09-2009, 05:48 PM

Quite the Vail circle jerk going on. Clearly, MTM did not read the ABA's most recent pronouncement regarding sexual relations with clients.

**gratzo** · 12-09-2009, 05:49 PM

Looks like whatever falls late this PM and this evening is it - nothing big lurking for overnight. A few inches MAX this PM, then it's dry along I-70 until Sat. The Fri/Sat storm doesn't do much for anyone, but the Sat night/Sun storm looks pretty good for southern and central mountains. I-70 might see another 6" out of this storm later on Sunday into Sunday night. Still 5 days away, but that's the way it seems. After the Sunday storm, it looks mostly dry for a while.

**Rontele** · 12-09-2009, 05:54 PM

Originally Posted by gratzo

Looks like whatever falls late this PM and this evening is it - nothing big lurking for overnight. A few inches MAX this PM, then it's dry along I-70 until Sat. The Fri/Sat storm doesn't do much for anyone, but the Sat night/Sun storm looks pretty good for southern and central mountains. I-70 might see another 6" out of this storm later on Sunday into Sunday night. Still 5 days away, but that's the way it seems. After the Sunday storm, it looks mostly dry for a while.

Gratzo, in this afternoon's forecast discussions the BOU office seemed fairly bullish on the Saturday night/Sunday storm for their mountains and so did the PUB office for their mountains. GJT kind of split the baby saying that it would start out better for the southern and central and then the focus would shift north...

SLC seems more in line with BOU and Riverton more in line with PUB. What gives?

FWIW, both the 18z GFS and the NAM seemed a bit more bullish towards the northern mountains than the prior GFS runs and the EC (which seems to distance the polar and sub tropical jets more)

**MakersTeleMark** · 12-09-2009, 06:49 PM

Originally Posted by Rontele

Quite the Vail circle jerk going on. Clearly, MTM did not read the ABA's most recent pronouncement regarding sexual relations with clients.

Your butthurt about your facet trip I believe started it off. Have you booked a bunk with Gratzo? And your inexperience is telling- only applies to current clients.