Mountain West Discussion

[raindancewx]

The SOI has crashed hard in recent days. Should be a decent system in the ten-day time frame from the crash, around 2/8. The big system of recent days for California moving east now times up well with the most recent crash.

Date	Tahiti (hPa)	Darwin (hPa)	Daily Contribution	30 day Av. SOI	90 day Av. SOI
29 Jan 2021	1011.25	1004.75	8.91	17.02	14.18
28 Jan 2021	1011.84	1002.75	21.11	17.56	14.30
27 Jan 2021	1013.31	1002.25	30.39	17.55	14.07

CPC also has a cold period in the time frame a storm would come through, so maybe some high ratio / low water content snow.

 

[ValpoVike]

7 hours ago, mayjawintastawm said:

Crazy inversion this morning. Below about 5500 ft it's 30, above it around 50 just a few miles away.

Inversions like this are fascinating to see.  A few years ago in February, I drove down 36 from Estes where it was 53 degrees and when I got to Boulder it was snowing and 18.

[Chinook]

The models are flip flopping too much on this potential storm. I don't really think any model has nailed down the synoptic situation.

[smokeybandit]

Yeah the GFS is all over the place

[smokeybandit]

GFS has lost the storm again over its last few runs for the Colorado eastern plains

[Chinook]

Sometimes the 120 hour time frame is when the models start to lock on to a storm and get some agreement. In this last couple of days, the 168-120 hour forecasts have been model hell. I think the models are getting closer, but the GFS/Euro are still having some issues determining precipitation with the front. The GFS has some areas of 0.5" QPF from Fort Morgan to Denver, the Euro has some snow bands (or even rain) that are quicker and weaker.

[mayjawintastawm]

I've tried not to even look at anything outside of 72 hours this winter, puts me in too bad of a mood. Will look tomorrow.

[Chinook]

Wind gusts are picking up to 30-50mph in Fort Collins and Loveland.

[mayjawintastawm]

It's raining here. I don't think I've seen rain in about 5 months. I have seen fire though.

[smokeybandit]

Palmer Divide did well, though the best of it was a few miles south of me. I ended up with just under 2".  Some spots south got 4"

 

 

[mayjawintastawm]

Interesting discussion on the MO/OK/etc thread about the 18z GFS at fantasyland time... OKC has like 40 inches of snow, about 10x what DEN has. Hide the sharp implements. Is there a D5 (all vegetation incinerates and moonscape ensues) drought level?

[ikcarsky]

Serious cold all the way to CA on the 12z CMC Sunday morning, 8 days from now.  It's preceded by an awesome overrunning snow event for N AZ and NM.  Weenie 10:1 snow map paints 2'+ for some of the NM western mountains and generously spits out 1'+ to much of the central and western part of the state.  Even if this did come to pass looks like a good setup for a canyon wind down the central mountain chain and much of ABQ metro still gets snow holed.  Anyway this all looks dependent on some delicate wave breaking action to occur in the North Pacific Ocean in a few days due to the current maturing cyclone south of Kamchatka, which spins off some vorticity into the Gulf of Alaska on Wed that pulls on a lobe of the NoAm TPV, elongating it toward the N Pac, or something like that.  My mind boggles at all the NPac vorticity lobes phasing and shearing and puking on the 500 mbar chart tbh but it does assure me that what the CMC shows is not gonna happen.

[Chinook]

19 hours ago, mayjawintastawm said:

Interesting discussion on the MO/OK/etc thread about the 18z GFS at fantasyland time... OKC has like 40 inches of snow, about 10x what DEN has. Hide the sharp implements. Is there a D5 (all vegetation incinerates and moonscape ensues) drought level?

Our fantasyland storms have barely even been interesting for a long time. I'm not posting any fantasy storms unless the Euro has 0.1" or 0.2" of QPF. As for me, I've gotten 14.1" since November 1st, compared to an average of 26.4" for Fort Collins. (1.26" compared to 1.73" liquid equivalent) It seems like the cold air is coming into the middle of the country, and *later* this week may be one of the few times my place will get below 10 degrees for the winter. Even at that, I've hardly gone outside on any cold day since I work from home quite a bit.

[ikcarsky]

Models seem to agree on spitting out a low from the current NPac cyclone chaos that heads toward the West coast, undercutting a ridge that gets set up over Alaska.  Key difference is Euro has a weak Alaskan ridge on D5 which breaks down and retrogrades toward Siberia.  GFS/CMC are stronger and keep the ridge in place longer, which together with the NPac low looks to entice the NoAm TPV to extend westward and swing some truly frigid air down the Rockies all the way to the coast.  I thought I remember hearing the Euro had a bias with breaking down ridges too quickly but that may be in the tropics, I don't remember.

[Chinook]

It is 53 degrees in Denver vs 22 degrees at Fort Morgan. I think the cold air may move westward quickly.

[raindancewx]

The GFS has something for NM/CO snow around 2/13-2/15 which makes sense to me. It is in line with the timing of the most recent SOI crash. 

I'm actually pretty optimistic for about a three week period from 2/22 to 3/15 for snow in New Mexico and Colorado. I don't really expect much before or after that. But it is possible I have the timing a bit off.

The years that have had measurable snow in Albuquerque in October have each had snow the following March. The favored dates tend to be around 3/10, which is consistent with the only time frame we've been able to get rain or snow in the city in the past eight months or so. The ten years with measurable October snow in Albuquerque average four measurable snows 2/22 to 3/15.

7/25-9/8-10/26-12/10-1/25--->3/10?  That's essentially the storm cycle this La Nina for Albuquerque.

There has also been a strong recurring tendency for big dumps of cold highs to come around day 25-30 of each 46 day cycle starting July 1, 2020. Albuquerque is essentially in the August/November portion of the cycle for now, where it seems like it should be pretty warm generally. The Sept/Dec portions were much more balanced, with a lot of cold and warmth, and that's likely to return in March. This is what I have for the high cycle in Albuquerque. Each number is the high minus the average. You can see pretty clearly the blues have concentrated at the some point in the cycle. Generally each cycle correlates to one or several prior cycles at an r-squared of about 0.2 to 0.5.

 

[mayjawintastawm]

17 hours ago, Chinook said:

It is 53 degrees in Denver vs 22 degrees at Fort Morgan. I think the cold air may move westward quickly.

 

Dropped 20 degrees in just under an hour (45 to 25) from 6:10 to 7:00 PM at my house yesterday, just after the wind dropped off. Stayed around 12 degrees all night long.

[Chinook]

Fort Collins-CSU had a temperature drop of 24.1 degrees in 10 minutes (5:20 to 5:30PM). As you can see on the image I posted, some stronger easterly winds yesterday advanced the arctic air. We had gusty westerly winds and quickly switched to gusty easterly winds. As of right now, APA (Denver/Centennial) is 20 degrees warmer than DEN. It will be interesting to see if the inversion breaks and Fort Collins or Greeley get up to 32 or something like that.

[Chinook]

As of right now, I don't have a lot of confidence in any particular forecast of snow. The only thing I really know is that the mountains will get snow on many of these days, and we may be in a sad situation: we will have cold temperatures be in place, while every other region around us gets snow. Nevertheless, models have some QPF. Somewhere in here, 00z Sunday to 00z Monday, we could get 2-6", as this 0.3"  in Fort Collins and Cheyenne could have 20:1 snow ratios.

[raindancewx]

Sunday (and maybe Tuesday) look promising for snow out here.

My guess is the system Sunday over NM will be the system that ends the severe cold pattern nationally. Not that the whole country will warm into the 80s overnight. But the 20-40 degree below average temperatures won't last too much longer.

Some pretty impressive cold is actually coming into the Northwest too.

[ikcarsky]

17 minutes ago, raindancewx said:

My guess is the system Sunday over NM will be the system that ends the severe cold pattern nationally.

 

NWS ABQ seems optimistic there could be a return.

GFS and ECWMF continue to prog a third system for Tuesday of next
week, keeping colder weather along with good chances for snow to much
of the forecast area. Drier and warmer weather appears on track for
late next week. The overall pattern in the Pacific is not expected to
change during the remainder of the February with additional trough
forecast to dig southeastward over the Southwest U.S. Credit a
convectionless EPAC with the MJO stuck in phase(s) 6/7 thanks to a
fading La Nina.

[raindancewx]

The pattern really isn't changing too much. It's just relaxing. It's hard to sustain the level of cold the Plains has been seeing.

[Chinook]

This will be a very good storm for the Colorado mountains, certainly compared to most storms recently. The values shown by the NWS for the plains are probably a blend of models, which predict light snow at various times, mostly focusing on Saturday night to Sunday night. My area got something like 1/4" of snow last night, which is the first snowcover in several days. The GFS and NAM have over 0.4" QPF in the immediate area, with high snow ratios on the Kuchera snow plots, so I suppose we may want to watch and see if snow amounts could be higher. And even in this cold, cold world, Craig, Colorado has -RA right now.

[ikcarsky]

One thing I've noticed in recent days is the modeled longwave pattern is more stable I can ever remember it (at least on GFS).  Even out to ~240 hours, the positions of troughs/ridges from run to run predicted for a given date haven't been changing much.  I suspect this will change once we're back to a faster zonal flow pattern.

In the meantime T-24h to the main show, NWS ABQ going with 2"-4" for the metro area.  Nothing staggering but at least it won't melt right away.  Plus the Tuesday system looks juicier than a few days ago.

[Chinook]

blue has taken over

[raindancewx]

Very curious to see how this changes by say, 2/1-2/16, for Texas, New Mexico and Colorado. This month will undoubtedly finish pretty cold nationally. By the end though, should be a lot warmer than even a month as recent as February 2019. CPC has the final week of February favored warm for most of the US. The cold in Billings and Bismarck and the north-central is still forecast to relax a lot in a few more days, generally after 2/17.

[ikcarsky]

Lightning!  Quite a show with the band ongoing north side of ABQ given the time of year, I'd say about 4-6 strikes a minute.  Lots of curly arcs poking beneath the cloud deck.  I don't even remember any instability progged by any model sounding, I'm quite impressed.  Very dynamic system -- gives me good feeling about snow tonight.

 

[ikcarsky]

Lol -- real life 0z ABQ sounding had 37 J/kg of MUCAPE, gotta love dynamic systems

Severe Thunderstorm Warning

---

Severe Weather Statement
National Weather Service Albuquerque NM
615 PM MST Sat Feb 13 2021

NMC001-043-140130-
/O.CON.KABQ.SV.W.0001.000000T0000Z-210214T0130Z/
Sandoval-Bernalillo-
615 PM MST Sat Feb 13 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 630 PM MST
FOR SOUTHEASTERN SANDOVAL AND BERNALILLO COUNTIES...

At 614 PM MST, severe thunderstorms with snow and hail were located
along a line extending from San Felipe Pueblo to Albuquerque, moving
east at 35 mph.

HAZARD...60 mph wind gusts.

SOURCE...Public.

IMPACT...Expect damage to roofs, siding, and trees.

 

[raindancewx]

The airport managed a staggering 0.03" with the line of thunderstorms. I just want the damn front to be through by Midnight. I hate when Arctic air comes in at 1 am and we have a high of 45 or 50 because it was that warm for 10 minutes very early in the day. I do like some snow for the city, but I think it's really a 3-4 hour window for Albuquerque to get snow. Some spots are probably going to get 6 inches in the NE heights, Rio Rancho, and maybe the West Mesa. I went 1-4", locally under 1" or up to 6" for the city.

[ikcarsky]

The action had mostly passed by this point.  The really heavy precip was maybe 90 seconds tops, small dense balls of snow, like a snow/graupel hybrid.  But: thundersnow confirmed.