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Mountain West Discussion


Chinook
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It's time for a new thread. Even though there is not too much precipitation in the forecast right now, I am sure we will be discussing mountain snows in just a few weeks. As for now, ensemble means show all the western areas having above normal temperatures until a trough comes into the Pacific NW on about Oct 10-11.

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my personal observations since the firey times started

AUG 2020
Aug 1: thunder in the area, evening light rain, 0.35" of rain
Aug 2: trace of rain
Aug 4: 0.04" of rain
aug 7: very hot
aug 14: Cameron Peak fire, smoke plume above
aug 15: Cameron Peak fire, smoke plume above, and smells of smoke, reduced visibility
aug 16: smells of smoke, reduced visibility
aug 18: high of 98-99 degrees in Loveland
aug 19: trace of rain, around 0.05" in Fort Collins
aug 20: lightning in the area, around 0.05" in Fort Collins and up to 0.02" in south loveland (none here)
aug 22: high of 95.4 here, 96-101 in Loveland. Smells of smoke in the morning, weird sky all day, smoke from california.
aug 25: high 95-97
aug 26: trace of rain
aug 28: 0.05"
aug 29: 0.02", shelf cloud, wind gust to 25mph or 30mph, possibly brief lightning
aug 31: 0.01"  sprinkles, light rain
AUG 2020 0.47"

SEP 2020
Sep 5: high of 96-97, heavy smoke, ash fell from the sky
Sep 6: high of 94-95 heavy smoke, ash fell from the sky
Sep 7: heavy smoke for part of the day, ash fell from the sky. Low 70's here but 80's and 90's elsewhere
Sep 7-8: 0.30" of rain/snow by morning. (little snow accumulation)
Sep 8-9: 0.63" water equivalent of snow (and possibly rain),  2.8" (CoCoRAHS)  (3.5" on car)
sep 9-10: 0.03" water equivalent of snow
sep 17: low visibility of 5-10 miles, perhaps a hint of smoke smell
sep 26: smell of smoke, strange colors later in day.
sep 30: smell of smoke early in the day, red sun later in the day (higher altitude smoke)
SEP 2020: 0.96"

OCT 2020
Oct 2: smell of smoke in the air. small amounts of ash fell from the sky. low visibility, 5 miles
Oct 5: smell of smoke in the air. small amounts of ash fell from the sky. low visibility, 5-15 miles, red sun

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This is going to be a really weird winter for our region. Pretty sure of that.

The storms are finally starting to show up in the long-range for the Northwest, which is good, that was what I expected. My best guess is the NAO will go negative, either substantially but only for a small time, or only a bit, but for an extended period, in December. I've had some good success using this method in prior years. March would likely be pretty negative too. My sense is the intense heat of Summer will show at times in winter, but you'll also see very intense waves of cold show. The worst case scenario for us would be that my reliance on ENSO order is irrelevant, and years like 2008, 1999, 1975, 2017 end up taking over somehow, instead of the La Ninas that follow El Ninos like 2016, 2010, and 2007 - relatively wet years generally.

Image

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What if we run out of letters on the Greek alphabet for tropical storms?

What if we retire Hurricane Delta? In the future, will we have to go directly from Tropical Storm Gamma to Tropical Storm Epsilon? It doesn't seem right, but if you aren't used to the Greek alphabet, it doesn't sound so bad.

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I mean...I've seen 90 point dew point depressions here. You all are just spoiled up there. The -PDO can really dry things out in the West if it lasts long enough, and Nino 4 finally getting knocked below average helps too.

The dew points here tend to run in the 30s/low 40s into October in a good monsoon year most days. When the monsoon fails it seems like dew points run from 10-30 most of the time in Fall. That's one reason I don't think it's a super hot winter though. It's going to be pretty dry, but with semi-regular cold fronts I think. So cold air moving in when dew points are -10, 0, 10, 20, etc. is a recipe for some pretty cold nights.

I've been looking at precipitation patterns by hurricane season activity here. December has a near 0 chance of topping average precipitation in a very active hurricane season (>160 ACE) in a La Nina. But it has a 50% chance in the other La Ninas, going back to the 1930s. The difference is statistically significant (p is 0.037 or so), and none of the other cold months are even close to that. ACE is still only at 111 despite 25 named systems. So December has a decent shot at being a good month. Not really optimistic about November even though I kind of expect a big cold dump in late October, probably the week before Halloween. I kind of get the impression there will be a good storm or storms by the end of October for much of NM, CO, WY.

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I kind of expect a big cold dump in late October, probably the week before Halloween. I kind of get the impression there will be a good storm or storms by the end of October for much of NM, CO, WY.

That does seem to be the trend in recent Falls, regardless of how hot they are, though this year the changes are all shorter and drier as compared to the last 3-4. 3 days of cold predicted 4-5 days out turns into a day, and QPF of an inch and a half turns into 0.5" or less 48 hours out.

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It's interesting...as hot and dry as it has been here, haven't really been many fires in New Mexico.

I'm not optimistic for overall snow pack with the hot/dry Fall, mostly because I think we have a hot/dry Spring too. But I am fairly optimistic for winter itself. 

The strongest La Nina winters, the lowest-sea ice cold ENSO winters since 2007, and +NAO La Nina winters all support a cold West winter look in some fashion.

EjyE0npXsAI9fhT?format=jpg&name=small

Above: Lowest sea ice extent in cold-enso years since 2007.

Below: Five strongest La Ninas (left), and La Ninas with a DJF NAO value of +0.4 or higher (right).

Strong-La-Nina-Composite.pngNAO-La-Nina.png

The 80-160 La Nina Ace composite also looks like these maps, and the Atlantic is at 122 ACE so far.

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My area has measured wind gusts up to 47mph right now with the cold front. That ought to mix away the smoke a little bit. Haven't had 45mph since the unusual derecho this summer.

 

Edit: 

max wind to 51 kt (59mph) at Denver

KDEN 112053Z 31035G47KT 3SM HZ SCT090 BKN150 BKN220 16/01 A2983 RMK AO2 PK WND 32051/2041 PRESRR SLP044 T01560006 53033

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The Euro has been showing a brief period with high pressure over Darwin and low pressure over Tahiti in a couple days. That'll probably crash the SOI pretty hard. So that'll likely put a storm over the SW sometime around 10/24. That time frame has been showing up in some of the methods I like as the approximate end to the dry spell here.

 

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These guys have a pretty good track record. They like similar snow in the West to last year. That'd be ~5-8 inches at the airport here, and 8-12 for most of the city. My raw analogs had 4.8" for Albuquerque, but my statistical regression for snow had 8.3". So I went with 7", but 5-8" seems pretty reasonable. Albuquerque can do well in a strong La Nina, 1988, 1973, were good here. But it's more likely we finish below average like 2007 or 2010. GFS also does kind of seem to see something around 10/24...fingers crossed.

12-OCT-LOG-8.png

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Yesterday, my area was totally clear except for some beautiful lenticular clouds. It has been probably 2 weeks or more since I saw the mountains with so much clarity, for example, 50 miles visibility out to the Indian Peaks. Today, it is clear, and I can see a little bit of smoke to my northwest from the active fire, with no haze/smoke in any other areas. Some of the trees are really changing to nice colors, although the wind knocked off a significant amount of leaves from a few trees. 

The GEFS shows broadly cooler air across the Midwest and into our area in the upcoming week.

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11 hours ago, Kitchener poster said:

What the heck happened to the Canadian Rockies. Went from moderate temps to incredible snow. The cold air anomalies just keep sweeping in for 2 weeks straight according to the GFS. 

On Saturday through Monday, some short-wave energy tracked into Canada from the Pacific, which wrapped up into a 500mb low in northwest Manitoba. There was dynamically cooling the air there, with lower 500mb heights. A ridge in Ontario ahead of this system pulled some warmer air aloft up into the Hudson Bay, which partially joined with a ridge over Greenland. The combination of ridging on all sides of the low in Canada is turning into a polar vortex with dynamically cooled 500mb air. This is just the time of year when air in the northern latitudes is cooling due to radiation loss, particularly with clear skies. So, much cooler air is developing at the surface. 

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We had a massive column of smoke from the Cameron Peak fire on Wednesday. At times, it looked tan and brown. At other times, it looked as dark as a thunderstorm in the north part of the sky. I think Fort Collins had ash falling from the sky. We also had a cold front come in at the same time, with easterly winds. The smoke smell wasn't too bad until today.

Edit: my place has got the ash falling from the sky today. The sun looks like it's as orange as a neon light. (3:00PM, not sunset.)

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Saw somewhere Phoenix had 144 days that hit at least 100 this year. Some of the top years prior to 2020 include 2003, which is a good match to this October, and 1989.

I used 87 degree highs here in La Ninas as a dirty metric, and we're at 112 of those. Thing is...a lot of the years with the crappiest monsoon precipitation and most consistent heat end up getting very cold. Examples include 1931, 1943, 1954, 2003, 2011, 2012. The crappiest La Nina winters are usually kind of average in at least parts of the Summer, say 2005, or 2017 as examples - not that dry and not that dry in the grand scheme of things.

My analogs for winter had the final 80 degree high in Albuquerque around October 20th - that looks about right. Still think there might be something around 10/24 for at least Colorado, in terms of decent moisture. The SOI has been fairly negative in recent days, at almost the same time and magnitude as in mid-October 2007, and there was a storm that went through late October.

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Well, that damn fire finally got us today. My neighborhood, The Retreat, was ground zero for today's fire.  This thing is an unbelievable monster. Just this morning the Sheriff office let me thru at sunrise to winterize my home since they had cut power. I took this photo from my deck at 8am before I left. At the time, the fire was still smoldering which you can see. Then at noon it went extreme and tore down the Miller Fork drainage. The other image is from Lily Lake looking over Estes Park back towards the Glen Haven area.

20201016_073232.jpg

122003751_10222832513976914_7007386585192368383_o.jpg

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On 10/6/2020 at 6:12 PM, raindancewx said:

. Not really optimistic about November even though I kind of expect a big cold dump in late October, probably the week before Halloween. I kind of get the impression there will be a good storm or storms by the end of October for much of NM, CO, WY.

Not quite, but this is getting into almost non-BS range now - it's 10/24 ish as promised earlier in the thread.

10-24-2020-ish-storm

 

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On 10/13/2020 at 10:58 PM, Chinook said:

this one is just for Mayjawintastawm... finally we have a long-range GFS run the connects the possible Caribbean hurricane with the cold front in New England

7wixbAd.png

Missed that post- been off the board for a bit. Wicked awesome!! Have to go over to the SNE forum to see what they’re saying.

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On 10/16/2020 at 9:14 PM, ValpoVike said:

Well, that damn fire finally got us today. My neighborhood, The Retreat, was ground zero for today's fire.  This thing is an unbelievable monster. Just this morning the Sheriff office let me thru at sunrise to winterize my home since they had cut power. I took this photo from my deck at 8am before I left. At the time, the fire was still smoldering which you can see. Then at noon it went extreme and tore down the Miller Fork drainage. The other image is from Lily Lake looking over Estes Park back towards the Glen Haven area.

20201016_073232.jpg

122003751_10222832513976914_7007386585192368383_o.jpg

F@&$king fire. Hope you and your neighborhood are ok. When will this pattern ever break?

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