Thursday, October 13th, 2022 3:30pm
Shawn and I went hiking up Quein Sabe the other day. It ended up being a weather forecaster’s curse day. A dark cloud seemed to follow us the whole 8-mile hike. It spit at us with rain and hail and then that changed to graupel and finally snow. It won’t be long before those flakes are flying around in the valley.
So what is Pagosa Weather’s Winter Outlook for 2022/2023? Are we going to have a white Christmas or do we need to do our snow dances again this year? Remember our dance from This is Pagosa last December: https://www.youtube.com/watch?v=tSGgmUZDAP0
First, let’s look back and see what kind of winter Pagosa Country had the last few years.
Recap of Winter 2021/2022
Last winter started out with an advisory for La Niña, the second winter in a row. A La Niña oscillation pattern usually means we have below average precipitation. In October and November we had just a few systems that left less than average snowfall.
We made up for that in December when 170” of snow fell at Wolf Creek. The snowstorm systems in December were directly correlated to an intensification of the Madden Julian Oscillation (MJO) in stage 7. It was strong enough to offset the influence of the La Niña.
However, the La Niña pattern fully kicked in for the rest of the winter keeping all systems to our north. The result was we had well below average snowfall the rest of the winter. We had a weak arctic outbreak in February, but it was not enough to offset the impact of La Niña.
By April, Pagosa had an average of 83” of snow, just 87% of the historic average of 95”. At Wolf Creek, the resort closed with 385”, 90% of their 430” average. We were very lucky to get the MJO snowstorms over Christmas and New Years. It saved our winter season.
Farmer’s Almanac Outlook Winter 2022/2023
Last year the Almanac had said Pagosa would have a “Cold but Dry” winter. It was dry if we don’t count December but our average temperature was above average.
This year, the old standby the Farmer’s Almanac says “Hibernation Zone Glacial, Snow Filled” winter.
Well, that sounds great! A good winter with above average snowpack would help erode our drought conditions even farther.
There are several other sources Pagosa Weather looks at for our winter seasonal outlook.
First, there are several different global oscillations Pagosa Weather can look out for a long-range outlook. 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 homogeneous 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?
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. If oceanic areas are their normal temperatures, pressure systems, associated fronts, and air masses move along, so storms give equal consideration to all parts of the country and everyone throughout the Intermountain West sees close to average snowfall totals.
However, differing sea temperatures can throw this schedule off.
El Niño-Southern Oscillation (ENSO)
After a strong El Niño 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 Niño and La Niña 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.”
The ENSO impacts oceanic temperatures near the equator. These temperature changes either suppress or enhance normal storm formations. Amazingly, these impacts at the equator result in changes thousands of miles north and to the normal Polar Front Jet flow as it circles the earth. Areas either see more lows and associated frontal systems or fewer.
If sea temperatures are too warm, an El Niño 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 Niño and Pagosa Country had near record snowfall. See Picture 4 and Picture 5.
If sea temperatures are cooler than normal, a La Niña pattern forms and the Pagosa area sees less than average snow. Winter 2017-2018, we were under a La Niña 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 there are other players that enhance or negate the impact of the ENSO…
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 effect 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 Niño 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!
On the other hand, if an enhanced area with a strong MJO were to move over our area during a La Niña winter, the MJO could negate the impact of the La Niña and allow storm systems to move further south and into our area.
That is exactly what happened in December of 2021. Wolf Creek received 170” of snow in a few weeks time, accounting for 44% of the season’s snowfall.
The Arctic Oscillation
The Arctic Oscillation (AO) is the wobbling of the arctic airmass that forms over the North Pole regions during the winter. Winter of 2020-2021 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 a thin dividing layer, the tropopause. Above the tropopause is the Stratosphere region, where temperatures increase with height. Record high temperatures indicated a very compressed and very, very cold arctic airmass.
It can be very difficult to forecast a polar vortex outbreak because that cold air spins like a top before it suddenly sends a bubble of frigid air south. The only thing we can look at is how extensive the snow fields are in Siberia.
The AO wobbled like a top for several weeks in January and February of 2021, before there were several Polar Vortex outbreaks. Surprisingly, it snowed in Spain. Texas had historical cold temperatures. And we had excellent snowfall the third week in February.
The Quasi-Biennial Oscillation
The Quasi-Biennial Oscillation (QBO) is a circulation of winds that occurs in the lower stratosphere above and near the equator. Again, the lowest level of the atmosphere where we live is the troposphere and above that is the tropopause, a thin layer between the two. Above the tropopause is the stratosphere. These lower stratospheric winds can impact the strength of global systems.
The QBO has a cycle of around 28 months. For about 14 months it is out of the east and then it weakens and reverses and flows out of the west for the next 14 months.
The QBO has been found to have an impact on the oscillations including the ENSO. In fact, if we look back at the winters where we have had a La Niña pattern and a westerly QBO, we had average to above average snow pack between the San Miguel-Dolores-Animas-San Juan and the Upper Rio Grande, the two river drainage areas in southern Colorado. In fact, in the winter of 2016-2017, a La Niña winter we had an average snowpack of 131% by the first of March.
So I know a lot of you are thinking, “Ok, Arleen, thanks for the science review. But I really need to know is there going to be enough snow so I can go for a ride with San Juan sled dogs? Or is our drought going to worsen this winter? Or is there going to be so much snow, I should run away to the Caribbean and return in April?”
Let’s take a look at each of these oscillations and see what they are forecast to do this winter. Then determine how they will interact with each other and what the result will be for the winter and snowfall in Pagosa country.
First, sadly, climatologists are forecasting an overall La Niña Winter which typically means below average snow fall for the Pagosa area and Wolf Creek ski area. By February, chances are equal that the ENSO will be neutral. With a neutral ENSO, the Walker Circulation in our area is able to move along allowing storm systems with their lows and associated fronts move through every 4 to 7 days dropping some snow each time one passes.
However, not all hope is lost just because it is a La Niña winter, again. 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 were 7 significant La Niña 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!
The MJO has been weak and incoherent for a few months. That explains why we’ve had very few tropical storms so far this season when it was expected to be active.
However, the folks at the Climate Prediction Center are looking for the MJO to finally intensify around the first of October….
The AO is currently neutral and fluctuating quite a bit. The Siberian snow cover extent is just above average at this time or 4.3% above normal. The Siberian snow over is 10% larger than it was at this time last year. The more extensive the snow cover, then the greater chance for a colder arctic airmass.
In addition, there is an “unusually early polar vortex disruption”. Al this points to the potential for Arctic airmass outbreaks this winter that could help our snow totals.
QBO just switched form easterly flow to westerly flow in September. It is expected to be weak in October and November, moderate in December and January, and moderate to strong in February. And strong in March.
Long Range Forecasts
Our Winter Outlook for Snow for 2022/2023
Based on the information we have at this time, Pagosa Weather winter outlook for Pagosa and Wolf Creek is that we will have BELOW average snow for October, November, and into December based on the impacts of La Nina. We could see weak influence from the MJO in mid December.
January will have near average snow.
As we get into February, the chance of an arctic outbreak increase. And the QBO strengthens helping to negate the impact of the ENSO that is also weakening at this time as the waters along the equator finally warm. The result will be February will have ABOVE average snow.
As we get into March the La Niña will release her grip and we’ll have neutral ENSO impact. In addition the QBO will now be strong. March and April will have ABOVE average snow.
It’s complicated but Pagosa Weather’s winter outlook at this time is that we’ll have AVERAGE snowfall for Winter 2022/2023. It’s just going to be slow to get going.
Pagosa Weather will continue to follow the oscillations and update you as more information becomes available.
Some articles for further reading and learning:
La Niña: 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/september-2022-la-ni%C3%B1a-update-it%E2%80%99s-q-time
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 and https://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/mjoupdate.pdf
Arctic Oscillation: https://www.aer.com/science-research/climate-weather/arctic-oscillation/