Mountain West Discussion

[Chinook]

6 hours ago, smokeybandit said:

Model wars going on with this eastern Colorado storm.  Very different solutions only 24 hours out

I think it's because there's a higher lapse rate near the 500mb low. Maybe models can't decide what to do with the banding of precipitation with some slight variations in lapse rate and higher values of vertical velocity. I'm not sure though. The liquid equivalent of snow and rain should be 0.20" to 0.30" near Denver. There is a winter storm watch for the Palmer Divide, and winter weather advisories for the mountains.

[smokeybandit]

Well that storm turned out to be a bust.

[raindancewx]

I think the models see very high down dew points down here and kind of go nuts with precipitation for the NM high terrain and Colorado. We had 0.19" rain, despite dew points at July levels (mid-40s).

On the other hand...I forecast 1.25" for Dec-Feb for Albuquerque in my winter forecast for October, with a high of 49.7F. Albuquerque is currently at 1.17"/49.3F for 12/1-2/22.

The storm did what I needed it to do. I had 7.5 inches of snow through February 28. We're at 6.5, although the distribution is pretty different. I did have a big November (we only average an inch here).

This was from my October forecast. Essentially, a lot of the cold/snow I expected for Nov-Dec concentrated in November. Obviously, November came in wetter than expected, wettest since 1905 here.

October was 68.2F / 0.59" / 0.0" snow.  November was 55.6F / 1.99" / 4.0" snow.

December was 47.8F / 0.30" / 0.4" snow. January was 48.8F / 0.30" / 0.9" snow.  February isn't over yet, but should finish around 53.5F/0.57"/1.2" snow.

[Chinook]

On February 15th (8 days ago) I posted a GEFS-500mb/SLP image for 240 hours (Feb 25th) that seems to partially correlate with today's weather (Feb 23rd.) There has briefly been some snow between Denver and Boulder today, but it must not have been too interesting.  Colorado Springs is still getting some snow right now. At my place, it is not snowing or raining currently. There may have been some drizzle or snow near Loveland today, but it has not been below freezing since yesterday. Coming up Tuesday and Wednesday, we should have some chilly weather. It seems like we will get much-needed moderate temperatures and fair weather, possibly until March 2nd or March 3rd.

[raindancewx]

The lack of snow pack right now compared to last year implies a much warmer March. The snow-less areas of Montana in some cases will literally be 20F warmer than last year. Billings finished 22 degrees below average last February.

[etudiant]

3 hours ago, raindancewx said:

The lack of snow pack right now compared to last year implies a much warmer March. The snow-less areas of Montana in some cases will literally be 20F warmer than last year. Billings finished 22 degrees below average last February.

Is there a drought issue, given a warmer than usual climate with a sub par snowpack?

[raindancewx]

2 minutes ago, etudiant said:

Is there a drought issue, given a warmer than usual climate with a sub par snowpack?

Have to see how Spring goes. You can get a lot of rain and snow in the West through May. Western snow pack is pretty average for most areas except Oregon, California, Nevada, and Arizona. The Rio Grande should be fine, the mountains surrounding the head waters are near average, and the lakes/reservoirs are pretty full still from last year. Elephant Butte Lake which supplies a lot of stored Rio Grande water to Mexico & far West Texas is the fullest it has been in over 10 years, since July 2010. The models/CFS and my own ideas also support a pretty wet March for New Mexico & Arizona, probably southern Colorado too which would help a lot. February/March more were super warm for years here, much more average lately, which has helped. I think we hit 75 on February 10th in Albuquerque in 2017, which means even the mountain tops likely saw some snow melt. None of that bs this year, so far.

 

[Chinook]

1 hour ago, etudiant said:

Is there a drought issue, given a warmer than usual climate with a sub par snowpack?

Some of California and Nevada have increased in drought coverage recently. It seems that the Sierra Nevada snowpack is not going to get a lot better soon.  Overall, the West has less drought than one year ago. As you can see, most of the snowpack values are pretty good, and Montana has about 117% of snow water equivalent in the mountains. Not too many areas of the West have been more than +2F for this February, so that is not too crazy. 

[Chinook]

This snow squall lasted for about 20 minutes (1503z is 8:03AM)

KFNL 241503Z AUTO 31024G35KT 1/4SM SN FG SCT005 BKN012 OVC075 00/M02 A2985 RMK AO2 PK WND 32035/1457 PRESRR P0000 FZRANO

[Chinook]

Yesterday, my area had temps of 27 degrees in the afternoon, with winds to 23mph gusting to 36mph at the airport. (wind chill of 13 degrees.) Even if you have lower winds in the city environment, the wind chill values are still much colder than the average temperatures of upper 40's to 50 degrees, for this time of year.

[smokeybandit]

My max wind gust was 45.  Made for some near whiteout conditions as the snow squalls came further west than expected.

[mayjawintastawm]

Yesterday felt like Chicago. Brr. Today was truly a 2-coat day: started at 9F and topped out near 45.

Feb precip at my place was almost 2 feet.(I'm guessing it's done). 65.2" on the season. Something tells me March will be like January though... hope not.

[raindancewx]

The CFS is actually going to my idea for April (I had an area of +5 or warmer NE/Great Lakes)...unfortunately it shows it for March. Oh well. We'll have to see how it verifies. If you look at 12/16-1/15, it was a pattern pretty similar to what is depicted below, but the huge warm area centered further south than what the CFS has. New England & Minnesota are in the 10th shade for warmth, something like +6 to +8 (F) on the scale.

[Chinook]

Models continue to show a lighter snow event on Monday (possibly morning).  I kind of hope it's wrong. Too much of this stuff has happened on Mondays and Tuesdays.

[raindancewx]

On 2/20/2020 at 11:17 PM, raindancewx said:

The Euro has a 985 mb Typhoon hitting east of Darwin, Australia in a few days. Once it weakens, there should be a pretty massive crash in the SOI, shortly before March, probably around 2/26. That would set up the 3/7-3/14 window I've been targeting for major SW precipitation for months pretty well if it happens, as you tend to get major precipitation events in the SW 10 days after a major SOI crash.

Big crash verified for 2/27-2/28. +16 to +2 in one day. Usually means a big storm in the SW after a drop that size. GFS already hinting at it yesterday -

[randomski]

Any ideas model wise as far as Aspen precipitation is concerned from 3/6 through 3/11? 

[Chinook]

This WPC blend of models shows the potential for 0.3" of QPF or 3" of snow or more for lower elevations, on Sunday to Monday. It's possible that 5-day storm totals may be at least 8" above 8000ft.

[smokeybandit]

Looks like a pretty snow-less first half of March for NE Colorado

[raindancewx]

Fairly promising for mountain snow along the NM/CO border over the next week. Timing is exactly right for the 3.5 month lag of the late Nov pattern. Also follows some big time SOI crashes, and the MJO is relatively favorable too.

[mayjawintastawm]

Looking like September and January along the Front Range. Could Albuquerque have a colder March than Denver? Sheesh.

[Chinook]

At the end of this East Coast storm, I may put a loop of the 500mb vorticity on my web site, because it's a 500mb phase. The GFS has 964mb off the coast by 06z, which is still today, in my time zone. Remarkably, this is yet another situation that screws the Boston-Washington corridor out of snow. 

Coming up soon, we'll have later sunrises, later sunsets, and the 00z models will be on the internet later in the evening. And 06z will be "tomorrow," technically.

[mayjawintastawm]

1 hour ago, Chinook said:

At the end of this East Coast storm, I may put a loop of the 500mb vorticity on my web site, because it's a 500mb phase. The GFS has 964mb off the coast by 06z, which is still today, in my time zone. Remarkably, this is yet another situation that screws the Boston-Washington corridor out of snow. 

Coming up soon, we'll have later sunrises, later sunsets, and the 00z models will be on the internet later in the evening. And 06z will be "tomorrow," technically.

I am kind of glad I don't still live in southern New England with this winter there... absolutely maddening for those who like snow there. "Missed it by THAT much" gets pretty old.

[Chinook]

This is weird.. and models have quite a bit of agreement at this time, which is also a little weird.

[Chinook]

It looks like a 500mb low will be in Arizona and New Mexico, on Friday morning, possibly tracking toward SE Colorado and SW Kansas. We will have to see how the models handle the synoptic details in the next few days.

[It's Always Sunny]

1 hour ago, Chinook said:

It looks like a 500mb low will be in Arizona and New Mexico, on Friday morning, possibly tracking toward SE Colorado and SW Kansas. We will have to see how the models handle the synoptic details in the next few days.

GEFS & EPS look favorable for potential severe across TX and parts of srn/cntrl Plains.

[Sydney Claridge]

29 minutes ago, It's Always Sunny said:

GEFS & EPS look favorable for potential severe across TX and parts of srn/cntrl Plains.

I'm surprised that SPC still has a "potential too low" in their Day 4-8 outlook.  There seems to be a pretty good chance that there will be severe thunderstorms later this week, particularly in the Texas/Oklahoma region, based on various model runs.

[raindancewx]

The GFS has what I call the 'legendary' pattern. Waves of subtropical moisture moving into New Mexico. Days on end. Cold enough for heavy snow in the mountains. I don't think I've ever seen a model depict this much moisture in New Mexico consistently in a non-monsoon month. It's probably way too much moisture, but verbatim, the mountains over 8,500 would get a foot of cement, and the highest mountains might get 3-5 feet, especially if the backdoor cold front helps wring out the moisture. That small area by Los Alamos is 3.0-3.5" precipitation, and it would be mostly snow.

[Chinook]

I did a little something different with this loop. It shows the 700mb-400mb relative humidity and SLP, so you can see the moisture streams joining up on the East Coast.

http://www.greatlakes.salsite.com/Mar_6_2020_700mb_loop.html

[Chinook]

There is some heavy rain moving into California and Arizona tonight, for lower elevations. Coming up, we will see a turn to stormy weather for the West and northern Plains, including a lot of snow for many areas of Wyoming, Montana, and possibly Nebraska.  This whole system should provide some helpful drought relief for areas of California and Arizona. As for the first storm, Friday and Saturday ,the whole situation may skip by the Denver area with light snow amounts.

[Chinook]

Now the "weird storm" is nearly upon us, as this will be the general setup tomorrow. Not as much snow will fall in New Mexico as previous forecasts had shown. Rain/snow should be fairly light near Denver. The only winter storm watches are for the San Juan Mountains and also central Nebraska.