Mountain West Discussion

[cstrunk]

3 hours ago, yotaman said:

I have a facebook friend in Denver and she posted that she got lots of damage in her area from golfball sized hail.

 

1 hour ago, Chinook said:

There was a picture on twitter of somebody who had house windows broken from hail in the Denver area. That's nasty stuff!

I also know someone in the area that had skylights broken in their house from about golfball sized hail yesterday.

[mayjawintastawm]

Since we moved here I have not seen reports of large to very large hail (2.75") so close to the foothills (within 10 miles, in Lakewood and Golden). Must take a fairly unique setup for that to happen. Fortunately, DIA, where my 2 month old car was parked for 5 days (!), did not get hail. Whew!

[raindancewx]

Was in a farming area of the Rio Grande Valley yesterday, and a lot of the farmers started to cheer when it started raining. Been a good wet year so far. The volcanoes west of the city were about as green as I've ever seen them, with grass and flowers in full bloom. The heavy rain and snow in late April likely helped some.

January-April here was the wettest start to the year since 2007. The Jan 1 to May 10 rain total here is nearly identical to the Jan 1 to July 31 rain total last year.

Worth noting: Jamstec just updated and has backed off the idea of a super-Nino for the winter, but still shows a pretty healthy moderate modoki/central based El Nino.

 

[Chinook]

I'm not sure what just happened here, but this may have been around Pueblo's low mountains.

[raindancewx]

Based on the seven variables I like to use for US winter conditions, this is what we have now for 2016-17 with the numbers (other than solar) final:

ONI in Nino 3.4, DJF: -0.4 

Nov-Apr AMO: 0.279

Nov-Apr PDO: 1.06

Modoki? Yes (Nino 1.2 anomalies way warmer than cold Nino 3.4)

Prior Yr ONI: El Nino (2.2)

ABQ Monsoon: 3.09"

Solar (July-June): ~28 Sunspots

Closest matches (using the previous ONI value) were 1931, 1931, 1944, 1976, 1983, 1983, 1998. Using years where "El before La" is more generalized, you get 1931, 1931, 1942, 1944, 1976, 1983, 1983, 1998, 2005.

I set the threshold for an analog as at least three similarities out of the seven (i.e. absolute value of prior year to current year is w/in a top 20 most similar yrs on 3+ variables), and it does produce the correct spatial pattern for the winter...although it isn't good enough to get the intensity of the anomalies right.

 

 

[Chinook]

The rainfall and snowfall has been very heavy in the last 21 days in SE Colorado and NW Kansas. In some cases, there was unprecedented snow in W Kansas around April 29. Unfortunately the snow during that time hurt some of the wheat crop and killed cattle.

[SluggerWx]

Awesome watching this cell roll into the Denver area this evening.

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[SluggerWx]

There's a pretty significant UH track in NE Colorado this evening on the NAM 3K. Looks like it starts around DIA from 02z and then really ramps up between 03z and 06z.

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[raindancewx]

I made a Summer outlook (NM/Albuquerque focused) for the US if anyone is curious. 

Outlook: https://tinyurl.com/kvkpq7u

Analogs were filtered from years since 1930 that went from Cold Neutral / La Nina conditions before Summer to El Nino conditions after Summer. I counted 14 years from that filter. Of those years, I then looked for years with a wet Nov-Apr in ABQ before Summer, a transition that was from a Modoki La Nina to Modoki El Nino, a +PDO Nov-Apr before Summer, a +AMO Nov-Apr before Summer, low solar activity July-June before Summer, and I looked for years that were at the end of an El Nino-->La Nina-->El Nino cycle over three years. When weighted, it gave a fairly wet cool (but not cold) Summer for much of the interior West.

The numbers came out to show ~15 rainy days (+4) in Albuquerque (>=0.1"), with 56 days at or above 90F (8 below the 85-year mean), and only 0-1 days at 100F (1-2 below the 85 year mean). The analogs said first 90F day here will be May 23rd - which looks about right, but last day 90F day Sept 1 - which would be fairly early historically. It's May 15 and we haven't had any 90F days yet, and none seem to be coming for the next week, it's like ~74F as I write this - so we're probably getting to 85F or so today before cooling off for a while.

[Chinook]

I saw some distant lightning tonight from a ~60dBz storm north of Fort Collins. The storm didn't look huge, but the CYS radar said it had tops of 40000 ft, so that's decent.  There are some nighttime MCSs (or at least showers and thunderstorms) tonight in KS/NE, WI, and the Dakotas, and accordingly, there were about four distinct areas of severe storms today/tonight. I wonder if tomorrow will feature more severe storm reports than today.

[Mercurial]

SW Montana and Eastern ID look to get snow down to the valley floors later this week.  Including Butte, Idaho Falls, and Pocatello.  lol.

[raindancewx]

11 hours ago, Mercurial said:

SW Montana and Eastern ID look to get snow down to the valley floors later this week.  Including Butte, Idaho Falls, and Pocatello.  lol.

I haven't tested it for areas outside NM, but low-solar years are supposed to cool the upper atmosphere. So here, that results in far more common late measurable snows, and sure enough it snowed April 29 (0.7"), which was 4th latest on record for measurable snow since 1931, had never snowed on April 29th back to 1931. Suspect late snows are more common with low solar in other spots besides NM, especially in places away from major bodies of water.

[Chinook]

The NWS gridded forecasts have a lot of snow for Montana, Idaho, and Yellowstone N.P. mountains. Later on, the GFS has some snow to 5000ft  here! Yikes. The 12z NAM is insane for Cheyenne. We don't need snow; too many leaves on the trees for that. I'm sure the same is true even for locations such as Laramie and Cheyenne.

[ValpoVike]

3 hours ago, Chinook said:

The NWS gridded forecasts have a lot of snow for Montana, Idaho, and Yellowstone N.P. mountains. Later on, the GFS has some snow to 5000ft  here! Yikes. The 12z NAM is insane for Cheyenne. We don't need snow; too many leaves on the trees for that. I'm sure the same is true even for locations such as Laramie and Cheyenne.

New WS watch for foothills between 6k-9k' Wednesday night thru Friday for up to 3 feet of snow.  I am really regretting my purchase of flowers and veggies...

[Chinook]

I have never seen 4" of rain in one day.  My personal record that I ever remember happening at my place, was at Toledo, 2006, with 3.55" in roughly 4 to 7 hrs of thunder. Other than that, if it rained more than that in one day, I was too young to correctly remember.

Here is a Wyoming -centered map of the NWS gridded forecast. Denver is at the bottom of the map. Rain and water equivalent of snow. Snow is above roughly 6000 ft. I might snow at my place. Hope you are ready to shovel snow, Valopvike! Not sure I really wish this upon you.

 

[ValpoVike]

Yeah, I sincerely hope this underperforms significantly.  I really wouldn't mind seeing 6"-8" as a final Spring hurrah, but the QPF forecasts are scary.  If you assume 10:1 (or even 8:1) ratios, if this verifies it will be a big problem for leafed out trees and power lines.

[Amped]

GFS showing 84" 10:1  in near Estes Park.

[ValpoVike]

That is fantasyland.  However I did notice a 1" increase in QPF forecast from WPC, up to 5.4" bullseye:

[raindancewx]

Even if it is cold enough to snow, and at night, you have to kind of go with lower snow ratios for these late events just because the ground is so warm and the sun is so high in the sky. I'd go with no more than 6:1 or 8:1 personally, unless you're super high up, say 8500+

[Amped]

43 minutes ago, raindancewx said:

Even if it is cold enough to snow, and at night, you have to kind of go with lower snow ratios for these late events just because the ground is so warm and the sun is so high in the sky. I'd go with no more than 6:1 or 8:1 personally, unless you're super high up, say 8500+

That's usually the idea. most of the mesoscale models have single digit snow accumulation below 6000ft.  Cold still be historic at 7500ft with 8:1 ratios expect a lot of tree damage.

[ValpoVike]

38 minutes ago, Amped said:

That's usually the idea. most of the mesoscale models have single digit snow accumulation below 6000ft.  Cold still be historic at 7500ft with 8:1 ratios expect a lot of tree damage.

We'll see, and I'll post pics.

[Amped]

 

Official forecast seems like a good starting point. GFS RGEM and GGEM are showing 8"+ LE in some areas, Hopefully that is overdone.

[raindancewx]

The fun thing about these systems is if the solar cycle is playing into the anomalously late/cold/south tendencies, that should continue for the next four or five Springs. I'm a fan, I like seeing the mountains out my window covered in snow in mid and late May. SILSO has limited solar predictions on their solar site, which has data back to 1749, and there is a case to be made this (near) minimum period will last from July 2016-June 2017 to July 2021-June 2022. The previous (near) minimum period was 2005-06 to 2010-11. Obviously 2006-07, 09-10 were kind of legendary in the Rockies/SW, and they both had low solar and El Nino conditions. Then you had 05-06 and also 07-08 which was kind of like this past winter, and the great cold outbreak of Feb 2011 during the 2010-11 Super La Nina which was nuts.

My average first 90F day here (1931-2016) is May 25 - it looks like we could blow past that date this year, and I'm a fan of that too. 

I told the guys at Weather5280 that in ABQ solar plays a big role in how late a last snow can occur (p<=0.05), including this year when it snowed on April 29th (fourth latest Spring date for snow since 1931) so if Denver gets 3-6" (<5800 feet) out of this I think you have to expect this type of thing for the next few years. I'm pretty sure even down here we had flurries/trace near Memorial Day (late May 2009) in the last La-->El transition near the minimum.

 

[mayjawintastawm]

Dang, yeah one of the few times I'm glad I'm not progged to get significant snow.

Last time we had QPF forecasts anywhere like this was September 2013. Yeah, that one. Even here we had 10+ inches of rain, with 5-6" falling in 24 hours. Though there was far more tropical moisture with that one, so I'm not afraid of flooding on that scale. Could be that some of the WE falling as snow might slow the runoff up in the foothills, which would help a lot.

[beavis1729]

Cheyenne is now expected to see 1-2 feet of snow today and tonight...just crazy for May 18.  Laramie may see 24-30".

[ValpoVike]

I picked up about 10" overnight, with 12 more forecasted today, 12 more tonight, and up to 9 tomorrow.  It is pasty cement, very heavy and wet.  Power has been going on and off, so I expect fully to be without power sometime today.  Unbelievable for 2H May.

[CO SciFan]

It's absolutely dumping huge flakes in Fort Collins. Some of the trees already look stressed by the snow.

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[ValpoVike]

21 minutes ago, CO SciFan said:

It's absolutely dumping huge flakes in Fort Collins. Some of the trees already look stressed by the snow.

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The flake size has also been consistently large up here.  I think the ratios may end up in the 10:1 range.  There was very little issue with overcoming the ground temps, and the sun angle is clearly not a hinderance given the thickness of the cloud cover.  Say a prayer for the trees

[Amped]

36 minutes ago, ValpoVike said:

The flake size has also been consistently large up here.  I think the ratios may end up in the 10:1 range.  There was very little issue with overcoming the ground temps, and the sun angle is clearly not a hinderance given the thickness of the cloud cover.  Say a prayer for the trees

Surprised you still have trees left.

[Chinook]

It is snowing west of I-25. I think I have 3-4".