Jump to content
  • Member Statistics

    15,389
    Total Members
    7,904
    Most Online
    crossbowftw3
    Newest Member
    crossbowftw3
    Joined
Chinook

Mountain West- Winter

Recommended Posts

GFS, 0.35 near DEN airport, 0.47" for Denver downtown, NAM, 0.90" for Denver.

If you like the SREF plumes for precipitation/snow amounts, the SREF plumes have essentially 0-16" for the Denver area. Thanks, SREF! That really narrows it down. I think 0" is too low.

Share this post


Link to post
Share on other sites

yes, 18z NAM still has pretty decent QPF from the Denver metro up to Fort Collins

3AM forecast discussion from Denver/Boulder

Quote
Another shortwave around the upper trough will reinforce the cold
push Tuesday with a 130 kt jet pushing into the Great Basin and
into southern Colorado. Pacific moisture will be entrained in this
system and moderate upward QG motion is expected. This will bring
in moderate to heavy snow at times to the mountains and spread
over the plains. For now, its looking more like 4 to 10 inches
over the high mountains, this time with less wind. Over the
plains, temperatures will likely only warm into the 20s, and 2 to
4 inches of snow may fall. The jet may produce banding, and
therefore highly variable amounts may occur over a short distance,
with some locally heavier amounts.

 

Share this post


Link to post
Share on other sites

-9F on GFS extended MOS for Fort Collins

--

      MON 05| TUE 06| WED 07| THU 08| FRI 09| SAT 10| SUN 11|MON CLIMO
 N/X  26  50| 14  28|  8  11| -9  13|  6  42| 24  41| 18  41| 21 16 44

Share this post


Link to post
Share on other sites

Just as the models were converging on 2-3" of fluff for Denver Metro, they diverge again. 00z GFS has a bullseye of 6" right over Denver (15:1) with about 0.35" QPF, and NAM has 1" or less with barely a few hundredths of QPF. Sigh. Given how dry it's been the NAM may be right, but hope it's wrong. I want to go live in a rainforest for a bit.

Share this post


Link to post
Share on other sites

The 00z NAM has 0.18" -0.20" for Denver I think.  Maybe it's these insanely low dew points that are keeping the models confused. Fort Collins had a dew point of -15F with the wind tonight.

Share this post


Link to post
Share on other sites

I've always despised the NAM QPF, especially close to an event. Regardless of my feelings, the NAM can be said to be an outlier for the Front Range. Not saying it can't be right, but it's on its own. I think the NWS is calling it correctly. A conservative forecast, and the opportunity to bump up totals if needed. I hope the GFS is onto something with some higher totals, though.

Share this post


Link to post
Share on other sites

Hey All - This is my first winter in Denver after a lifetime in New England. I don't know much about the micro-climates and nuances with storm systems here like I do back home. What should we watch out for? I've been hearing the last couple days that some model outputs are putting a bullseye (for the plains) around the Denver metro. What needs to happen to overperform the consensus of 2-4"?

Thanks!

Share this post


Link to post
Share on other sites

I'm pretty new to the area as well, and I'm sure others have better perspectives. In general what you'd like to see for good accumulations along the Front Range would be favorable jet position, but even more so easterly flow. Ideally the easterly flow would be deep (surface to 500mb) and with good fetch, but in this storm it's pretty shallow (not much above 700 mb). This is anticyclonic upslope (i.e. due to clockwise flow around an area of high pressure to our north) as opposed to cyclonic upslope, which would be due to a low to the south of the Denver metro. I think in general anticyclonic upslope doesn't "perform" as well as cyclonic. Of course we're also dealing with an extremely dry, arctic airmass.

Either way I'm looking forward to seeing some snow!

Share this post


Link to post
Share on other sites
46 minutes ago, nrhardin said:

I'm pretty new to the area as well, and I'm sure others have better perspectives. In general what you'd like to see for good accumulations along the Front Range would be favorable jet position, but even more so easterly flow. Ideally the easterly flow would be deep (surface to 500mb) and with good fetch, but in this storm it's pretty shallow (not much above 700 mb). This is anticyclonic upslope (i.e. due to clockwise flow around an area of high pressure to our north) as opposed to cyclonic upslope, which would be due to a low to the south of the Denver metro. I think in general anticyclonic upslope doesn't "perform" as well as cyclonic. Of course we're also dealing with an extremely dry, arctic airmass.

Either way I'm looking forward to seeing some snow!

Same and thanks for the information! Forecast looks great in the mountains for the next week. Took Friday off to ski Breck for the day.

Share this post


Link to post
Share on other sites

The storm got going slowly and it started to accumulate at about 7:00PM. We have had 3/4" to 1" in the last 4 hours. We had a very low dew point of -10F today while it was still partly sunny. Now the dew point has recovered to 17F

 

Share this post


Link to post
Share on other sites

11 degrees here in western Broomfield this morning, with 4" of fresh powder on the ground. The last inch or so was pure fluff, with nice dendrites. Easily 20-30:1 ratio stuff. I enjoyed an early morning trip to Boulder in the snow, before traffic got going. 

Share this post


Link to post
Share on other sites

The 12km and 4km NAM were both too dry for this storm for the cities/plains, as of the 00z and 18z runs last afternoon/evening. They may not have been too low on QPF amounts for the mountains. I'll have to note that for future storms.

Share this post


Link to post
Share on other sites

The NAM is supposed to have trouble with precip at the level of ~5,000 feet, but it does a lot better higher and low from what I remember reading about it. It's not bad overall, tends to be a little high in my area inside 24 hours.

Share this post


Link to post
Share on other sites

Fort Collins got down to -5F, and around -10F outside the city limits. Casper WY got to -30F last night. There's been nothing comparable in Casper since February 2014. Looks like urban areas of Denver got down to -2F to 2F.

----

Edit: Casper hit a low of -33F, the most recent roughly equivalent temp was -32F on Feb. 17 2006.

Denver hit a low of -10F at DIA

Fort Collins-CSU hit a low of -7F.

---

Conditions at: KDEN observed 08 December 2016  12:53 UTC
Temperature: -22.2°C (-8°F)
Dewpoint: -24.4°C (-12°F) [RH = 82%]

Share this post


Link to post
Share on other sites

The most recent runs of the GFS were not that crazy for this part of Colorado, but still 4-5" of QPF could be possible over 10000ft in southwest Colorado in the 7-10 day time frame.

Share this post


Link to post
Share on other sites

Bah, so far this map is what is what I was expecting in January, not December. Still nice to see cold in the West. Look at the icebox, or as we call it Wyoming.

Cold in the West Dec 1-8.png

Share this post


Link to post
Share on other sites

The 12z and 18z GFS today have more snow for eastern Colorado with that large storm system on Friday-Saturday. It is still a long way out, so I expect snow forecasts will change.   It won't be a closed upper low at 500mb or 700mb. One thing I expect: temps near 0 on either Saturday or Sunday.

Share this post


Link to post
Share on other sites

My third winter in the west and shaping up to be more typical or maybe even above average?  11" of snow so far this month at my house.  12 - 18" forecast in tomorrows storm then strong cold to continue...  Mount Bachelor ( 21 miles from my home ) has more than a 5' base and 146" at the base so far the season.. photo from my "attempted" ski day on Sunday.. 

 

 

 

 

Bachelor12:11:16.jpg

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Recently Browsing   0 members

    No registered users viewing this page.

×