Mountain West Discussion

[AfewUniversesBelowNormal]

Huge North Pacific High +bias on models right now day 4-11. It doesn't organically sit like that, everything happening around it. It's not handling stratospheric waves maybe(although that's probably not right). Should be interesting to see what actually happens, big difference in conditions mountains and coastal west

[Chinook]

20 hours ago, raindancewx said:

Looks like we have a non-trivial (~20%) chance of a 20 point SOI drop from January to February, which has happened in ~1.3% of months since 1931? SOI was +8.9 in January. For February 1-6, its -21.4.

 

Shouldn't that increase the subtropical jet a lot?

[raindancewx]

^^Possibly. The GFS says the subtropical jet is heading north directly over the SW...most precip its shown for NM/AZ since probably late Sept or early Oct.

The national look in Dec-Jan temperature anomalies has things that I like for a wet March - Dec-Jan 1980-81 was very hot in the West, slightly cold in the East, cold in TX, after a major hurricane hit TX, and it had a much colder Nino 1.2 than Nino 3.4. January 2018 was the coldest Nino 1.2 reading since January 1981 on the ERSST V.5 data. 1980-81 had high solar activity, which does make me nervous. Rare to get heavy precipitation here in March in low-solar years.

https://www.esrl.noaa.gov/psd/data/correlation/nina1.data

This isn't a great match for the intensity of heat in the West, but its kind of the right idea for Dec-Jan - I tried to pick years that were East/West splits on cold/hot, and blended in some Modoki El Nino years to incorporate the warm PDO ring and emphasize the intense cold in Nino 1.2 relative to Nino 3.4.

[Chinook]

NWS and the models (in general) now have 3-4" of snow for most of the Front Range over the weekend, so kind of like what I said 2 days ago. Shouldn't really be a major event for the plains or the mountains.

[Chinook]

55.5 degrees at 9:30PM, that's an almost-summer temperature for this time of night.

[Chinook]

The 12z GFS was kind enough to give our area 2"-4" of snow for this weekend. For some reason, the NAM and 3km NAM have struggled with predicting snow on the east side of the mountains at short ranges. The NAM has totals that are lower-- perhaps too low by an inch. Good luck, Missouri.

[ValpoVike]

We have dropped from 51 degrees to 24 degrees in a half hour, and went from beautiful blue skies to ~300' visibility in fog.  I captured this photo of the fog quickly rolling up the canyon.

 

[Chinook]

Valpovike, that is pretty neat! Yesterday, here, we had fog pretty early, maybe 3/4 mile visibility or less. The front came through before sunrise. There was just a bit of freezing drizzle and snow before 11AM. Then, it stopped, and thankfully the roads didn't ice over. Then we started getting snow at 7PM or 8PM. Today (Saturday) We've gotten about 2" now, so obviously there wasn't a sustained snow for over 12 hours.

[Chinook]

Heavy (?) snow for Denver right now

[raindancewx]

The models are an absolute mess for next week. GFS/Euro have some kind of series of wet STJ waves/moisture making it to NM, but when they get here, timing, amounts, it all changes massively. Thursday-Saturday is the general time frame, maybe up to an inch of rain in the city, some big snows for the mountains of the North. I'm somewhat suspicious that within 3-4 days of the event it will either rapidly diminish in intensity OR somehow join up with some cold and become a much bigger event. The MJO is nearing phase 8 now, and phase 7-8 can be a wet pattern for us...although not particularly cold.

The SOI crash has started to flatten out a bit, it was only -1 or so for 2/10. Does look mostly negative through 2/17, before some big positive readings come in, so the window for an active subtropical jet is probably through 3/15 to 3/20. If the MJO wave continues to phase 2/3 (its been re-entering the same phase every 49-55 days since 11/26), would probably reach phase 3 around 3/4 to 3/10, and the transition out of phase 3 would be the end of the window for the SW for a while. 

I remain cautiously optimistic for March...but the last wet March in the city was 2007.

[Chinook]

12-24" is possible in the San Juan mountain range, something that has been sorely lacking

[raindancewx]

Hope we get some rain in the valleys this week. The highs this winter are only behind the Great $#%**iness that is 1933-34 for the city. My idea that this winter has some Dust Bowl characteristics nationally is verifying given the extent of the dryness/heat. Of course, even in the 1933-34 winter we had 0.11" from Dec 1-Feb 11. So far: 0.03".  That 0.03" isn't dead last, somehow its 0.01" ahead of 1966-67 for winter to date.

Albuquerque has had at least one measurable snow for every cold season from 1931-32 to 2016-17 (Oct-May). If we ever go snow-less, will be from a lack of precipitation, not a lack of cold, as even our warmest cold-seasons feature ~70-80 lows under 32F, +many other nights near freezing when precipitation would be snow. We've had 61 lows <=32F so far. I'd guess we have 10-30 left given how dry its been, so cold isn't really the issue. 1966-67 had its first snow on Feb 27th. Issue is in warm DJFs here, only 5-20% of total precipitation in winter is snow, and with 0.03" total precipitation...that's just trace. Last year we had 1.90" precipitation in DJF, but only ~11%  was snow, 2.8". 

The SOI crash is still massive for Feb 1-12: -17.56 (down 26.5 pts).  Looks mostly negative through 2/17, at which point its probably too late to reverse out of the negatives by 2/28.

The European is now forecasting the MJO to reach phase two in late February...but it looks too fast. I think this is the fabled March year. The first wet March since 2007 for the city and the southern 2/3 of NM. That is what I went with in my Spring Outlook too. https://t.co/85VPbQq1bD

[Chinook]

An area near Alberta's Rocky Mountain front warmed from -29F to 34F in 24 hours (12z Monday to 12z Tuesday)

[raindancewx]

If the NAM is right, record wet soundings for the SW, and a winter worth of precip near Mexico in the next 60-hours. 

Odds of a near-record drop in the SOI month/month are no longer trivial, with the odds of a 20-pt drop at 36% now, 25x more likely than normal. I'm a bit nervous for my area, as dewpoints are still in the low teens. We're gonna waste a lot of moisture if that doesn't change fast.

 

 

[Chinook]

Snow may be possible for Denver on Tuesday. Some of the GFS runs have shown a lot of snow, but things have been really iffy this year.

[mayjawintastawm]

Given the lack of weekday snow so far this season, even a moderate event in the Urban Corridor would probably ensure a rush hour that lasts the entire day, and car accidents numbering in the tens of thousands. Was away for last weekend's overperformer, was in DC where I saw more rain in 2 days than we had here in 6 months. My wife said we got 4-4.5" of fluff.

[Chinook]

Bozeman Montana State U. Campus is up to 102" of snow for the season.

Colorado Springs Airport just doubled their seasonal snow total this past weekend. They got 4" on Saturday to take the seasonal total to 8.5"

[Cobalt]

5 minutes ago, Chinook said:

Bozeman Montana State U. Campus is up to 102" of snow for the season.

Colorado Springs Airport just doubled their seasonal snow total this past weekend. They got 4" on Saturday to take the seasonal total to 8.5"

How much do they average per year?

[Chinook]

9 hours ago, Cobalt said:

How much do they average per year?

NWS Nowdata says 86.9" for Bozeman- MSU climatology, although there is a bit of missing data. However, Bozeman-Gallatin Airport has a much lower average. Maybe that one is on the wrong side of a mountain.

[finnster]

1 hour ago, Chinook said:

NWS Nowdata says 86.9" for Bozeman- MSU climatology, although there is a bit of missing data. However, Bozeman-Gallatin Airport has a much lower average. Maybe that one is on the wrong side of a mountain.

I know you are talking about Bozeman, but a little weather history:  In the 1979-80 winter Fort Collins received 114" of the white stuff (I was here and got to enjoy every bit of it, but even I have to admit that winter I was ready for it to end ).  In this day and age it just does not even sound possible, although as recently as the 2009-10 winter I believe Fort Collins got just under 80"....

[finnster]

23 hours ago, Chinook said:

Snow may be possible for Denver on Tuesday. Some of the GFS runs have shown a lot of snow, but things have been really iffy this year.

Yea things have been really iffy this year, although northern CO has gotten in on some small snows this winter that I doubted would happen at all.

[ValpoVike]

The northern mountains have done well.  It has been kinda weird up here.  We would kill for a good dumping in the Estes Valley, but just a short drive up to 9000'+ it has been a pretty decent year.

Colorado SNOTEL Snow/Precipitation Update Report
Based on Mountain Data from NRCS SNOTEL Sites
**Provisional data, subject to revision**
Data based on the first reading of the day (typically 00:00) for Thursday, February 15, 2018
Basin   Site Name Elev (ft) Snow Water Equivalent Water Year-to-Date Precipitation Current (in) Median (in) Pct of Median Current (in) Average (in) Pct of Average         LARAMIE AND NORTH PLATTE RIVER BASINS   Arapaho Ridge 10960 14.5  14.6R 99  14.5  16.0R 91    Columbine 9160 15.4  17.1  90  17.5  18.4  95    Deadman Hill 10220 14.4  11.3  127  13.9  11.4  122    Joe Wright 10120 12.2  14.4  85  20.6  17.9  115    Never Summer 10280 13.2  13.9R 95  10.8  N/A  *   Rabbit Ears 9400 11.3  16.8  67  17.0  21.4  79    Rawah 9020 8.1  7.3R 111  11.4  9.8R 116    Roach 9700 10.3  11.3  91  13.0  13.2  98    Tower 10500 23.7  32.0  74  22.9  28.6  80    Whiskey Park 8950 15.8  18.8  84  18.1  20.3  89    Willow Creek Pass 9540 9.9  8.4  118  10.6  9.3  114    Zirkel 9340 18.5  20.6R 90  23.1  21.3R 108  Basin Index (%) 90  97

[raindancewx]

CPC has a cold March for the NC/NW US right now. Will be interesting to see what happens, given the MJO should be in 2/3 in early March BUT, the NW in particular is heavily favored to be warm after a big -SOI February, the negative correlations approach -0.7 in WA.

The precipitation correlations for the NW/SW are also very strong in March v. the Feb SOI, I think the whole West has a shot at near-normal to wet conditions, although -SOI is a big dry signal for the NW, particularly Washington.

[Chinook]

7 hours ago, finnster said:

I know you are talking about Bozeman, but a little weather history:  In the 1979-80 winter Fort Collins received 114" of the white stuff (I was here and got to enjoy every bit of it, but even I have to admit that winter I was ready for it to end ).  In this day and age it just does not even sound possible, although as recently as the 2009-10 winter I believe Fort Collins got just under 80"....

No, it was 88.7" in 2009-10. That was a little much. This was greatly impacted by 25" in October 2009. Obviously we are going to have El Nino with some of the right conditions to get close to this again. I might be possible in 10-20 years.

[mayjawintastawm]

Is there a cyclic nature to El Nino/La Nina years? When my son was born 20 years ago I called him (privately!!) "El Nino" because 2 of his first three winters were strong El Nino years, which in southern New England (where we were) ended up warm and wet, and most skiing was done wearing trash bags in the pouring rain. But the last several years now that I'm in CO we can't buy even a weak one, it seems. It's either La Nina or some sort of neutral thing. The winter we came out of that pattern, though (I think it was 2004-5) we had like 120 inches of snow, the first time ever that I truly got tired of it. I bought a snowblower the following year. I think 100" is my magic number for nirvana snowfall.

[raindancewx]

^^ If you look at just winters, I'd say it is cyclical. There are extended periods without La Nina, Neutral, El Nino. For instance, I don't consider any of the winters between 1956-57 and 1964-65 to be La Ninas. Also don't consider any of the winters between 1930-31 and 1939-40 to be El Ninos. The Dustbowl, with the extended dryness and random incredible heat nationally (especially for that era when the Earth was somewhat colder) may have been a function of no El Ninos for close to a decade.

You get long periods without Neutrals too, but long-term it does seem like its a 40-30-30 split in favor of Neutral. A period without Neutrals for a long-time would be 1968-69 to 1977-78. All of those winters are El Ninos or La Ninas in an ONI sense.

Functionally though, the El Ninos with -PDO conditions and La Ninas with +PDO conditions end up being pseudo Neutral in terms of conditions. Similar to how TX and the SE may end up cold this winter but much of the NW/NE, maybe NC will end up warm this winter despite the La Nina.

My general view is that in the SW, El Nino winters following ~La Nina winters are colder/wetter/stormier (1972-73, 1986-87, 1997-98, 2009-10, 2014-15) and the same holds true in the NW in La Ninas after ~El Ninos (think 2016-17, 1983-84, 1998-99)

[finnster]

3 hours ago, Chinook said:

No, it was 88.7" in 2009-10. That was a little much. This was greatly impacted by 25" in October 2009. Obviously we are going to have El Nino with some of the right conditions to get close to this again. I might be possible in 10-20 years.

Good catch on 2009-10 snow I got my number wrong.  It was a healthy amount of snow for sure.

[finnster]

2 hours ago, raindancewx said:

^^ If you look at just winters, I'd say it is cyclical. There are extended periods without La Nina, Neutral, El Nino. For instance, I don't consider any of the winters between 1956-57 and 1964-65 to be La Ninas. Also don't consider any of the winters between 1930-31 and 1939-40 to be El Ninos. The Dustbowl, with the extended dryness and random incredible heat nationally (especially for that era when the Earth was somewhat colder) may have been a function of no El Ninos for close to a decade.

You get long periods without Neutrals too, but long-term it does seem like its a 40-30-30 split in favor of Neutral. A period without Neutrals for a long-time would be 1968-69 to 1977-78. All of those winters are El Ninos or La Ninas in an ONI sense.

Functionally though, the El Ninos with -PDO conditions and La Ninas with +PDO conditions end up being pseudo Neutral in terms of conditions. Similar to how TX and the SE may end up cold this winter but much of the NW/NE, maybe NC will end up warm this winter despite the La Nina.

My general view is that in the SW, El Nino winters following ~La Nina winters are colder/wetter/stormier (1972-73, 1986-87, 1997-98, 2009-10, 2014-15) and the same holds true in the NW in La Ninas after ~El Ninos (think 2016-17, 1983-84, 1998-99)

Raindance can probably provide more details, but the decadal cycles of both the Pacific (PDO) and Atlantic (AMO) have an effect.  For example, when a +PDO and -AMO coincide it seems to result in more prevalent colder and stormier weather patterns in CO.  This was the scenario from the mid-70's, 80's and early 90's.  In recent years we seem to be trending to +PDO overall but the AMO is also staying positive as well.  Some say the AMO should start trending to negative but haven't seen much evidence of that happening.

From what I've seen in Colorado I think Raindance is right on about the SW - El Nino winters following La Nina winters are colder/wetter/stormier.  That was certainly true on the CO front range in 1972-73, 1997-98, and 2009-10.  Maybe we will be due for this next winter - once can hope     

[Chinook]

Kind of an interesting possibility of precipitation for Week 1 of March. This is almost looks like an El Nino general DJF average precipitation anomaly. The temperature forecast for this week very much favors cool weather in the west. Green means that I would be shoveling snow. Flagstaff, most of CO, and Nebraska and SD would certainly be snowy if this was right.

[Mercurial]

On 2/15/2018 at 7:27 AM, Chinook said:

NWS Nowdata says 86.9" for Bozeman- MSU climatology, although there is a bit of missing data. However, Bozeman-Gallatin Airport has a much lower average. Maybe that one is on the wrong side of a mountain.

They're both in the same valley, but Bozeman-MSU is tucked at the southeastern corner of the valley against the Gallatin and Bridger mountains, whereas Gallatin Field is located in the middle of the valley about 400 feet lower than MSU, and is actually in an entirely different town with a way drier microclimate.  So, it's legit.  I used to live in Bozeman, they have super sharp microclimates around that valley.