nrhardin Posted December 4, 2016 Share Posted December 4, 2016 I'm liking the trend of the trough digging a little harder and sticking around longer. Curious -- what's the actual QPF for those cities? Link to comment Share on other sites More sharing options...
Chinook Posted December 4, 2016 Author Share Posted December 4, 2016 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. Link to comment Share on other sites More sharing options...
nrhardin Posted December 4, 2016 Share Posted December 4, 2016 Looked like the mean was just shy of 5", with most members there or less. I'd take 5" and run at this point. 18z NAM wasn't too shabby either. Link to comment Share on other sites More sharing options...
Chinook Posted December 4, 2016 Author Share Posted December 4, 2016 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. Link to comment Share on other sites More sharing options...
Chinook Posted December 4, 2016 Author Share Posted December 4, 2016 -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 Link to comment Share on other sites More sharing options...
mayjawintastawm Posted December 6, 2016 Share Posted December 6, 2016 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. Link to comment Share on other sites More sharing options...
Chinook Posted December 6, 2016 Author Share Posted December 6, 2016 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. Link to comment Share on other sites More sharing options...
nrhardin Posted December 6, 2016 Share Posted December 6, 2016 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. Link to comment Share on other sites More sharing options...
sfenn1117 Posted December 6, 2016 Share Posted December 6, 2016 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! Link to comment Share on other sites More sharing options...
nrhardin Posted December 6, 2016 Share Posted December 6, 2016 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! Link to comment Share on other sites More sharing options...
sfenn1117 Posted December 6, 2016 Share Posted December 6, 2016 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. Link to comment Share on other sites More sharing options...
Chinook Posted December 6, 2016 Author Share Posted December 6, 2016 first flakes here! Link to comment Share on other sites More sharing options...
Chinook Posted December 7, 2016 Author Share Posted December 7, 2016 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 Link to comment Share on other sites More sharing options...
PennMan Posted December 7, 2016 Share Posted December 7, 2016 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. Link to comment Share on other sites More sharing options...
Chinook Posted December 7, 2016 Author Share Posted December 7, 2016 I got a little over 4". Link to comment Share on other sites More sharing options...
Chinook Posted December 7, 2016 Author Share Posted December 7, 2016 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. Link to comment Share on other sites More sharing options...
raindancewx Posted December 8, 2016 Share Posted December 8, 2016 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. Link to comment Share on other sites More sharing options...
Chinook Posted December 8, 2016 Author Share Posted December 8, 2016 pic from today Link to comment Share on other sites More sharing options...
Chinook Posted December 8, 2016 Author Share Posted December 8, 2016 storm reports here. Note- about 1-2" in Cheyenne Link to comment Share on other sites More sharing options...
Mercurial Posted December 8, 2016 Share Posted December 8, 2016 lol... -30 to -40 yeah sure why not. Link to comment Share on other sites More sharing options...
Chinook Posted December 8, 2016 Author Share Posted December 8, 2016 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%] Link to comment Share on other sites More sharing options...
Guru Of Reason Posted December 8, 2016 Share Posted December 8, 2016 9 hours ago, Mercurial said: lol... -30 to -40 yeah sure why not. And zero degrees in Seattle. Link to comment Share on other sites More sharing options...
Chinook Posted December 9, 2016 Author Share Posted December 9, 2016 This could be helpful for the western snowpack. Link to comment Share on other sites More sharing options...
Chinook Posted December 9, 2016 Author Share Posted December 9, 2016 My mind exploded thinking about this. The GFS has 5.00"-11.24" of QPF for southwest Colorado, 1.35" - 1.55" for me. Link to comment Share on other sites More sharing options...
nrhardin Posted December 9, 2016 Share Posted December 9, 2016 That would be excellent for snowpack, and the plains drought. I'd love it, too. Regardless it looks pretty cold for the next couple of weeks. Link to comment Share on other sites More sharing options...
Chinook Posted December 9, 2016 Author Share Posted December 9, 2016 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. Link to comment Share on other sites More sharing options...
raindancewx Posted December 9, 2016 Share Posted December 9, 2016 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. Link to comment Share on other sites More sharing options...
Chinook Posted December 12, 2016 Author Share Posted December 12, 2016 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. Link to comment Share on other sites More sharing options...
snownut Posted December 13, 2016 Share Posted December 13, 2016 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.. Link to comment Share on other sites More sharing options...
Chinook Posted December 14, 2016 Author Share Posted December 14, 2016 some areas of UT, NV, OR, ID, and WA are over 110% snow water equivalent Link to comment Share on other sites More sharing options...
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