What can we expect for the rest of January and then for February and March
There currently is a nice two-foot layer of snow in O’Neal Park and about 15 inches in the valley. Up at Wolf Creek there is a solid summit depth of 106”! However, we don’t see anything significant in the short-range forecast. It is time to look at the long-range forecast and see when we can once again experience the wonderful snow that we had for Christmas.
Arctic Oscillation (AO)
The Polar Vortex has finally set up and it is a stretched oblong vortex set up over Greenland and northern Europe. According to Dr. Judah Cohen who writes the weekly AO blog, such a pattern will lead to mid- to late-winter wave amplification over North America and favors extreme weather. Also of note in the arctic regions, “Arctic sea ice extent 2021 at the end of December is the highest in recent years and the 2nd highest in 18 years”, according to the US Snow and Ice Data Center.
Madden Julian Oscillation (MJO)
The recent snowstorm systems in December can be directly correlated to an intensification of the MJO in stage 7. It was strong enough to offset the influence of the La Nina. It will be approximately another 60 days before we are under the stronger stage again. There are weaker enhanced stages, but I doubt they would be strong enough to counteract the influence of the La Nina.
El Nino Southern Oscillation (ENSO)
A La Nina Advisory is still in effect. Sea Surface temperatures are forecast to remain below average resulting in suppressed storm activity in the equatorial regions for the next few months. The impact in North America is that the polar front jet stays farther north. When this happens, it is difficult for the southwest flow regime to set up. The southwest flow is our ideal snow system pattern.
My Winter Snow Outlook Update
January will be fairly dry. We’ll have an occasional cut off low wander over or occasional slough from a northwest system. The result will be a few inches of snow here and maybe 6-10” of snow at Wolf Creek. We’ll have below average precipitation in January.
February looks better. We should see an arctic outbreak system the second or third week of February. The result will be a good series of snow events and cold temperatures. We should have average precipitation in February.
The evil La Nina should release her grip in March just in time for the Madden Julian to circle back to us. March is a transition season often resulting in more active weather as the polar front jet reforms to the north. March should be an active month and have above average precipitation and snowfall.
If you would like to read more about the AO, the MJO, or the ENSO, here are a few links to recent blogs.
Arctic Oscillation and Polar Vortex Analysis and Forecasts: https://www.aer.com/science-research/climate-weather/arctic-oscillation/
Madden Julian Oscillation: https://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/mjo.shtml#current
El Nino Southern Oscillation: https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/ensodisc.shtml
Friday October 15th, 2021 7:45pm
The snow on Tuesday got all of us in the winter state of mind! It leaves us with the question as to how much snow will we see this year? The mullein was so tall this summer. Is this a sign that we are going to have a lot of snow? Maybe. It’s probably more of an indication of a wet spring. Now, how thick the down is on a duck might indicate how cold it will be. I couldn’t find a duck who would let me check its feathers. Pagosa Weather does have other tools….
First, let’s look back and see what kind of winter Pagosa Country had last year.
Recap of Winter 2020/2021
Last year started out with an advisory for La’ Nina. A La’ Nina oscillation pattern usually means we have below average precipitation. However, Wolf Creek didn’t look like it was having a La’ Nina winter at all in November and December!
Halfway through December had all the makings of an atypical La’Nina winter. In the mountains, Wolf Creek was hit by four events of 2’+ snow events for a total of 135”! Wolf Creek Ski Resort was the first in the lower 48 to open, the first to have 100% of acreage open and had the 3rd deepest snow base behind Mounts Baker and Hood. Wolf Creek averages 430” a year and they had 31% of their annual snow fall before Christmas.
Unfortunately, things really slowed down in January and through most of February. Fortunately, the third week in February Pagosa Country was hit by a series of storms that were the result of a chunk of the Arctic Oscillation breaking away, allowing cold air to sink south and setting up a few southwest storms for us.
By the end of March, Pagosa had an average of 78” of snow, just 83% of the historic average of 94.8”. At Wolf Creek, the resort closed with 362”, 84% of their 430” average. This actually isn’t bad for a La’ Nina winter.
Farmer’s Almanac Outlook Winter 2021/2022
The old standby the Farmer’s Almanac says “Cold but Dry” winter. See Picture 1.
Last year the Almanac had said Pagosa would have a moist but warm winter. We started out that way but didn’t end up that way.
Another dry winter would exasperate our already poor drought conditions. It takes average to above average snow pack to reverse the drought conditions. So how else can Pagosa Weather predict a seasonal outlook?
There are a number of different global oscillations Pagosa Weather can look out for a long-range outlook. In order to understand how these oscillations impact us we need to review some basic earth science.
Always remember, weather happens because the atmosphere wants to be the same temperature and pressure everywhere! It’s always trying to equal out. There are air masses of constant temperature, humidity and pressure that form over source regions.
These source regions are large land and oceanic areas around the globe. Due to the rotating earth, centrifugal forces, centripetal forces, and pressure gradient forces, these high pressure air masses slide around, creating areas of low pressure, associated frontal systems and weather along the way as they all try to equalize.
Here in Colorado, we are impacted by the following modified air masses: Maritime Polar (wet, cool), Continental Polar (dry, cold), Continental Tropical (dry, hot), Maritime Tropical (wet, warm), and Arctic (dry, very cold). Maritime Polar and Maritime tropical colliding with Continental Polar can come together and set up a good snowstorm for us if the systems move at us from the southwest. What are the controlling factors of these air masses? See Picture 2.
Oceans are much slower to cool or warm than land masses. Over oceanic areas, the way in which systems and air masses circulate is referred to as oscillation. In the central Pacific, the primary oscillation system is the Walker Circulation. This system assists moving pressure systems, associated fronts, and air masses along, so storms give equal consideration to all parts of the country and everyone throughout the Intermountain West sees close to average snowfall totals. See Picture 3.
However, differing sea temperatures can throw this schedule off.
El Niño-Southern Oscillation (ENSO)
After a strong El Nino event in 1997-1998, weather folks have learned to pay more attention to the El Niño-Southern Oscillation (ENSO) and we have learned how the El Nino and La Nina events can impact our winter snow accumulation. “La Niña is sometimes referred to as the cold phase of ENSO and El Niño as the warm phase of ENSO.”
If sea temperatures are too warm, an El Nino pattern results and the Pagosa area sees more than average snow. However, that can vary wildly. Winter 2018-2019, there was just a weak El Nino and Pagosa Country had near record snowfall. See Picture 4 and Picture 5.
If sea temperatures are cooler than normal, a La Nina pattern forms and the Pagosa area sees less than average snow. Winter 2017-2018, we were under a La Nina pattern and saw little snow. See Picture 6 and Picture 7.
The main impact of either a cold or warm ENSO event is that the pattern gets STUCK. But not whole story…
Madden-Julian Oscillation (MJO)
Circling the global around the equator is the Madden-Julian Oscillation (MJO). The Madden-Julian can be broken down into eight different stages that continually circulates around the globe. The stages are different areas of suppressed and enhanced areas. It takes 30-60 days for this pattern to complete a circulation around the globe. This oscillation influences typhoon/hurricane development as well. In addition, it can be weak, or it can be stronger.
Depending on where its areas sit, it can influence the Walker and therefore the systems impacting us. In addition, it can counteract the affect of the ENSO. Or it can magnify the intensity. For example, if a large enhanced area with a strong MJO were to move over our area during an El Nino winter, we could see some very strong storms that have the potential to drop a lot of snow. Especially, if this all happens with an Arctic Oscillation outbreak!
The Arctic Oscillation
The Arctic Oscillation (AO) is the wobbling of the arctic airmass that forms over the North Pole regions during the winter. Last year there were indications of record stratospheric temperatures over the polar regions.
Remember, we live in the Troposphere, where temperatures decrease with height. Above that is the Stratosphere region, where temperatures increase with height. Record high temperatures indicated a very compressed and very, very cold arctic airmass. It wobbled like a top for several weeks before there were a number of Polar Vortex outbreaks. It snowed in Spain, Texas had historical cold temps, and we had good snow the third week in February.
So, you ask, “Arleen, what about this winter? Do I need to get a new pair of POW skis or should I keep the rock skis handy?”
First, sadly, climatologists are forecasting a La Nina Winter which typically means below average snow fall for the Pagosa area and Wolf Creek ski area.
However, not all hope is lost. Joel Gratz over at Open Snow (a web page devoted to snow forecasts for ski resorts) has pulled data from winters of 1979-2016. During those years, there were7 significant La Nina episodes. During that time, 3 of the 7 winters, Wolf Creek had less than average snow (orange dot), 2 winters were average (which for Wolf Creek is 480 inches, the town of Pagosa has an average of 100), and TWO of the winters were above average (blue dot)!!! See Picture 9 – best viewed on a desktop or have your magnifying glass handy.
Come on! Let it SNOW like 2007-2008!
Currently, the MJO is weak. We are transitioning from an enhanced phase to a suppressed phase. Given the cycle of the MJO, it we should be under the influence of another strong enhanced phase by mid-December. That will last about a month. If it moves according to it’s normal schedule, we should be back under an enhanced phase by the end of February into March. For the MJO to counteract the La Nina, it would need to be stronger than it is right now.
The AO is currently neutral. The Siberian snow cover extent is just average at this time. The more extensive the snow cover, then the greater chance for a colder arctic airmass. However, a few scientific articles point to the possibility of a strong AO similar to last year.
Based on the information we have at this time, Pagosa Weather winter forecast for Pagosa and Wolf Creek is that we will have below average snow for the rest of October, November, and into December. In December, the MJO will counteract the affect of the La Nina. Wolf Creek will have good snowfall for the holidays. The latter part of January will have below average snow. As we get into February, the combination of the impact of a the AO outbreak plus enhanced MJO area, will give us more than average snow. As we get into March the La Nina will release her grip and we’ll have neutral ENSO impact and we’ll have average snow. April is looking to have average snow as well.
It’s complicated but Pagosa Weather’s forecast at this time is that we’ll have a little less than average snowfall for Winter 2021/2022.
Pagosa Weather will continue to follow the oscillations and update you as more information becomes available.
NOAA maintains a blog about monitoring and forecasting El Niño, La Niña, and their impacts on the Climate.gov page. If you want to learn more read these articles:
La Nina: https://www.climate.gov/news-features/blogs/enso/meteorological-winter-over-how%E2%80%99d-we-do-2017-18 and https://www.climate.gov/news-features/blogs/enso/march-2018-enso-update-come-water%E2%80%99s-fine
Madden-Julian Oscillation: https://www.climate.gov/news-features/blogs/enso/what-mjo-and-why-do-we-care and https://www.climate.gov/news-features/blogs/beyond-data/no-butterflies-just-tropical-rainfall