Collapsing thunderstorms with Mount Graham peaking out – Pic taken 4/7/2026.
Thursday – 28 May 2026 – 3:20pm (updates are in purple font)
“In every raindrop, I see the reflection of a world reborn.” Author Unknown
After another abysmal winter we are all looking forward to a good monsoon. In this article I’ll review last year’s monsoon, our recent winter, the ingredients for a good monsoon, what we take into consideration when forecasting the monsoon, what we can expect for this summer’s monsoon season, and finally a far distant look to next winter.
Summer 2025 Monsoon: We were in Neutral ENSO. The monsoon started on June 20th giving us .26″ for June. We had 1.55″ in July and only .98″ in August. Fortunately, in September we had 2.58″ (average is 2.00″). That put the Monsoon season at 5.37“. Our average monsoon season is 6.25”.
Then October hit and we were visited by Tropical storms Priscilla and Raymond and had SIX inches of precip for a month that normally sees 2.27. It erased drought for much of the county. That increased the Monsoon Season ’25 total to 11.37″.
Winter 2025/2026 Obituary: The La Nina ENSO pattern set up for the winter months. Waters in central Pacific zone 3.4 were as cold as -.9oC. In addition, it was an easterly QBO which can enhance a western ridge. The MJO was not active. The Arctic Oscillation was active which can be good. However, only Alaska, northeastern United States, and Europe benefited from the numerous arctic outbreaks. In addition, there was an unusually warm pool of waters detected in the Atlantic northern waters at the beginning of the winter that may have been a player in the unusual pattern.
The result was a massive, ugly ridge of high pressure that formed off the California coast and extended north of Washington for most of the winter. This left the entire Rocky Mountain region on the south side of all the good snow action that was taking place well to the north.
Pagosa Springs averages 100″ of snow each winter and Pagosa Springs ended the season with just 37″. Wolf Creek averages 360″ of snow a season. Wolf Creek Ski Resort closed this year on April 5th with only 192″. The only winter that had less snow in the last 57 years was 1976/1977 when Wolf Creek measured just 187″ of snow.
The snow pack in the southern San Juan mountains was just 10% on the 1st of April. This is historically the lowest amount since 1979 when the National Water and Climate Center Snotel network was completed.
Fortunately, it was a wet April. Pagosa saw CoCoRaHS precip reports from 1.82″ to 2.77″. All locations were above the average of 1.38″.
After two abysmal winters in a row coupled with one of our lowest historical snow packs, we need a good, wet monsoon.
Monsoon Numbers: The average monthly precipitation in July in Pagosa Springs doubles from what we see in June of .93″ to 2.01”. This is due to the North American Monsoon that impacts the southwest region from early July till the end of September. Some years it begins earlier and other years it lasts longer. In a few notable years, like last year, it lasts much longer when we have an active Pacific tropical storm season and tropical moisture remnants are caught up in the southwest flow as the monsoon weakens in September and October.
August is our wettest month of the year with an average of 2.69” of precip. Since the monsoon tends to weaken in September due to temps in the upper levels cooling and the subtropical ridge weakening, the average precip for September drops to 1.85”.
A review of Earth Science to understand the Monsoon
Let’s review a little basic earth science before we discuss what we can expect for a monsoon this year. If you believe the earth is flat, you’re not going to like the first earth science fact. The earth is round! Technically it is an oblate spheroid.
As the earth spins, Coriolis, Centrifugal, Centripetal, and Pressure Gradient Forces tug and pull at each other to give us our six primary circulation zones. We live under the northern Ferrel Cell and have westerly winds. If the earth were uniform, our winds would be nice and steady out of the west, and we wouldn’t have much to report to you each day.
The Earth’s Airmasses
The earth is broken up by massive areas of ocean and land. These areas cool and heat differently. Ocean areas are slower to warm and cool. Weather airmasses form over the ocean or large land areas that have homogeneous temperature and humidity stretching over hundreds to thousands of square miles.
Note: The San Juan Mountains are NOT an airmass source region due to the rugged topography.
A Continental Polar airmass forms over the high plains of Canada, a Maritime Polar airmass forms over the Gulf of Alaska, a Continental Tropical airmass forms over the desert southwest and, Maritime Tropical airmasses form over the Gulf of Mexico and the Baja area.
We have three seasons in the Pagosa area. Key airmasses during the Winter season are the Maritime Polar and the Continental Polar (to a lesser degree Continental Arctic) airmasses from October to March. Our Dry season includes April, May, and June and is influenced by the Continental Tropical airmass. The season that we are discussing today in the monsoon season in which the key airmasses are the Maritime Tropical airmasses from both the eastern and western gulf areas interacting with the Continental Tropical airmass.
These airmasses migrate from their original location due to the circulation zones and oscillations. When they interact with other airmasses, the fun begins! Areas of low pressure and fronts form, and weather happens!
Throughout the year these airmasses strengthen and weaken. For example, the lack of sun during the winter strengthens the Canadian Polar airmass which is dry and cold. And during the summer, the long days and strong solar radiation strengthens the Gulf Maritime Tropical airmass which is warm and moist.
The warm and moist Maritime Tropical airmass interacting with the hot and dry Continental Tropical airmasses are important pieces of the North American Monsoon.
What is the monsoon?
“The term monsoon describes large-scale wind shifts that transport moist tropical air to dry desert locations, such as the southwestern United States. A monsoon pattern also affects several other locations around the world including Southeast Asia, Australia, Africa, and South America. The Indian Monsoon is the strongest in the world due to the height of the Tibetan Plateau.”
As the earth tips towards the sun, North America warms, the polar front jet and associated pressure systems and fronts move north and weaken. At the same time in southern Colorado, the upper-level winds switch from the west to the east and the area falls under the influence the Hadley cell for about three months.
Lifecycle of the North American Monsoon
Early Monsoon Sputters: Typically, late June through mid-July there will be sputters of the monsoon as the pattern tries to ramp up. This early monsoon is characterized by high based, dry thunderstorms. May and June are typically our dry season and fuels will be dry. Relative humidities will be lower. These early thunderstorms with lightening but little rain can touch off wildfires.
Peak Monsoon: If the pattern can set up properly by mid-July and hold strong, we should see monsoonal showers and thunderstorms about every day through mid-August.
Late Monsoon: We tip away from the sun and areas supporting the subtropical ridge start to cool. The ridge weakens and so does the easterly flow. That puts southwestern Colorado back in the sputter and start events towards the end of August through the beginning of September.
As we get into September, the Pacific waters are warm enough for tropical storms to really intensify. A Pacific tropical system can feed into our monsoonal flow and then the good times really take off with potential for widespread heavy rains and localized flooding. These Baja area storms can last well into the night.
Note: It takes longer for Pacific storms to get going compared to the Atlantic due to how deep the Pacific is and that the east Pacific is cooled by northerly ocean currents whereas the Atlantic is warmed by southerly currents.
Four Ingredients for the North American Monsoon
1. Intense Heating
“Intense heating of the land over Mexico and the southwestern United States in the early summer months creates the wind shifts in the low levels.”
Note: Model data are algorithms based on current data from observations and satellite data built into a grid and run through a supercomputer. See this link for a more in depth explanation. https://pagosaweather.org/weather-101/what-are-weather-models/
The farther the model forecasts into the future the less reliable it is as depicted in the graphic below. Based on this a one month to four-month forecast is going to look like a squiggle. But it is a great place to start!
2. Strong 500 millibar (mb) ridge
500MB averages 18,000 feet in a standard atmosphere. Meteorologists like to look at this level to determine where the atmospheric highs and lows are (the surface can be deceiving). The larger the height, the warmer that column of air is. It’s a great tool! We use the term “ridge” for a bubble of warm air. Another description is a High in the upper levels with anticyclonic or clockwise turning.
To be a strong ridge, it should be at least 595 decameters.
3. Position of the Ridge
Position of the ridge is important too. We want it to stay to our east, positioned from the southern plains to the four corners.
If it drifts to our west, over Arizona and Utah, our moisture is cut off and the atmosphere is more stable. That is exactly what happened in 2021 but southern Arizona had the 3rd wettest monsoon on record! But the ridge was too far west for Archuleta County. We saw some afternoon showers but it was from moisture wrapping up and over the ridge and approaching us from the northwest rather than the southwest. In that case we get lee side, drying affect rather than orthographic lift.
Below are a few studies from the Albuquerque NWS office.
4. High Surface Dew Points
Next, we can look at the surface dew points across Arizona to see if moisture is slowly moving into our area to provide fuel for those afternoon thunderstorms. Moisture can wrap from the Gulf towards the northwest and into the desert southwest or it can also move northeasterly out of the Baja area. At the peak of the monsoon we want to see dew points of 50 degrees and above.
Below are charts showing the dew points at several locations to our south in the summer of 2021. The red lines indicate the average for those dates. The blue line is the current years dew point. As you can see, all locations were fairly dry in June and saw an uptick into July. We look closely at the steering flow to determine which site to track.
So those are the ingredients for the North American Monsoon. What evidence can we take into consideration to determine the monsoon season outlook?
Three Considerations for the Monsoon Forecast
There are several parameters we can examine to determine what sort of monsoon season we will have.
1. Correlation to Arctic Oscillation (AO)
When the AO is in its positive phase, a ring of strong winds circulating around the North Pole acts to confine colder air across polar regions. This belt of winds becomes weaker and more distorted in the negative phase of the AO, which allows an easier southward penetration of colder, arctic airmasses and increased storminess into the mid-latitudes.
In the graph below, you can see the AO has been neutral but is going positive at the beginning of June to the middle of June. This is a good trend for the building of our subtropical ridge. The Polar Front Jet should be migrating north and weakening.
For the purpose of a strong monsoon pattern, we want the AO to stay positive with the stronger winds staying north rather than slipping south into the mid-latitudes. This can interrupt the building of our sub-tropical ridge. This is not a concern till July.
2. Tropical Cyclone Activity
Over oceanic areas, the way in which systems and air masses circulate is referred to as an 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 that we are impacted by weather systems and receive precip on a regular basis. However, differing sea temperatures can throw this schedule off.
A common query I have received lately is, “I’ve been reading about the Super El Nino? That means we’ll have a good monsoon, right?” No, it does not…
In order to answer that question, we have to look at what has been happening with and at the current El Niño-Southern Oscillation (ENSO) forecast.
First, what is the ENSO? According to the National Oceanic and Atmospheric Administration (NOAA), “El Niño and La Niña are the warm and cool phases of a recurring climate pattern across the tropical Pacific ENSO. The pattern shifts back and forth irregularly every two to seven years, and each phase triggers predictable disruptions of temperature, precipitation. These changes disrupt the large-scale air movements in the tropics, triggering a cascade of global side effects.”
The Sea Surface Temperatures are measured across the Pacific near the equator. They have found a correlation between North American effects and area 3.4 in the middle of the Pacific.
The sea surface temperatures in the central Pacific have been NEUTRAL (La Nada) since the middle of February. Temps have been warming since the beginning of January. Current temperatures are right at +0.5. If they continue to warm, they will cross into the El Nino phase.
There is a 92% increasing to 98% probability we will be in El Nino phase for the months of July, August and September. This forecast often changes with the June forecast based on the summer ocean currents. It takes one to two months for impact to be seen in North America after transition.
When we are in an El Nino pattern the polar front jet is stronger. Remember the #2 ingredient for the Monsoon is a strong subtropical ridge. The polar front jet is supposed to take a summer vacation, weaken and stay in Canada. When the polar front jet remains active and dives into the far into the southern Unites States it knocks down the subtropical ridge.
Let me be clear: El Nino is detrimental to our monsoon!!! It weakens the subtropical ridge.
Summer 2023 was an El Nino by May with ocean temps up to 1.6 by September. We only had 3.23″ of precipitation over the three month monsoon season. This summer is warming slower then 2023.
The Atlantic hurricane season forecast is for Below-Normal Season. The El Nino impacts in the equatorial area increases wind in the formation areas and shear the forming tropical storms.
The opposite occurs in the Eastern Pacific. The winds in the Pacific equatorial area in lower and allows increased tropical storm formation. The forecast for the Eastern Pacific is for Above-Normal Season. We are normally impacted by remnants of Eastern Pacific storms at the end of August into September and the beginning of October.
We know that the first named storm will be Andrea. We hope she sneaks in and her residual moisture and visits us similar to Alberta two years ago. We’ve sent her an invitation to visit Pagosa Springs!
Though the actual tropical storm does not travel that far inland to the Pagosa area, it is not unusual at all for us to see the tropical storm remnants advected into our area as we saw in October of 2025.
The moisture from the remnants of tropical storms is different from our typical monsoon storms. The moisture of our typical monsoon storms has to travel about 1,500 miles and the storms last just a few hours.
The moisture from the remnants of tropical storms in the Baja area only has to travel a third of that distance or about 500 miles. The moisture is very deep and the air is very unstable. The storms can last several hours to a few days.
3. Low Snowpack/Above average Monsoon Correlation
The Tucson and the Albuquerque National Weather Service Offices have done studies where they have found, “A significant correlation exists in the observed data such that wet winters in the Southwest are generally followed by dry monsoons, and dry winters are generally followed by wet monsoons.”
The logic is that with a shallow snowpack deep warm temperatures set up earlier in the season. Those warm temperatures help turn the winds to the east to facilitate the formation of the monsoon.
Here is southwest Colorado, our snowpack was at just 13% of normal in April. Areas in New Mexico are at an abysmal 1%… Based on their study, we should have an above average monsoon.
I was curious as to whether there was a correlation to our snowpack and to our monsoon moisture so I looked a back at the last twelve years of data for snowpack in April and in May as compared to the summer monsoon. I also looked at southern Arizona’s snowpack. The inference is that with a low snowpack, the surface temperatures will start heating sooner and the ridge will start building sooner leading to any early onset monsoon season.
Note there are two previous springs where the snowpack was less than average and we were in a La Nina ENSO the previous winter: 2013 & 2014. The monsoons seasons were 5.57, 2.56, and 9.32″. Not much of a correlation there.
Unfortunately, based on the data I analyzed, I could not find a true correlation for Pagosa Springs. I thought I would still share the data with you. Another possibility is that it might be that 12 years is not large enough of a sample size. This is something I will continue to study and track.
Note: 2018 was the worst year in recent history with 14% snow pack by May 1st. And we only had 2.56″ of precip for the monsoon. It was also a La Nina year. However, the ridge set up too far to the west and left us high and dry under northwest flow. That is a concern this year.
Official Monsoon Season Outlooks
First, the National Weather Service Climate Prediction Center three-month precip forecast shows that the monsoon would be leaning above average for July, August, and September for southwest Colorado.
Keep our horse graphic in mind.
The GFS (North American Model) seasonal forecast for Jul/Aug/Sep is not available at this time. I will update this forecast when it is. The Jun/Jul/Aug chart indicates above average.
The Euro Model seasonal forecast is showing average to above average precipitation for southwest Colorado for the months of July, August, and September.
This forecast has been tweaked from a month ago and looks more in line with a typical monsoon season with an easterly subtropical ridge.
The Canadian seasonal forecast is expecting ABOVE average precipitation for southwest Colorado for the months of July, August, and September. It is showing the highest probability. This is more in line with a classic monsoon pattern and agrees with the CPC outlook.
Pagosa Weather’s Monsoon Forecast
The Pagosa Weather Forecast for the ’25 Monsoon season:
– The ridge was to our west all winter and is what kept our winter pattern from setting up. We have seen a more active transitional pattern in April and May with a few cooler outbursts and an active jet pattern.
Based on low snowpack that same subtropical ridge should set up early. Position is important. We need to see warm temps in the southern plains and the position of the ridge to our east. As a result we should see an early onset of the monsoon in late June.
– July and August should have average to above precipitation. Remember, we have to keep an eye on the ridge and make sure it does not drift too far west. Also, we have to hope the impacts of El Nino do not start early. This will knock down our ridge and weaken our monsoon flow.
– September should have at least average precipitation. The temperatures cool and the ridge weakens as we tip away from the sun. The El Nino pattern should be fully set up by this time and this enhances eastern pacific tropical storm activity. If we see the remnants of just a few of those storms moving in from the Baja area we will see at least average precipitation for the month.
The Pagosa Weather Monsoon forecast is that we will have an above average monsoon overall.
Winter 2026/2027 Far Far Far Outlook. Remember the horse drawing for model resolution depiction. This is not a smudge. It is a dot on the wall. But I am getting lots of questions on this after our last winter. Plus “Super” El Nino is the biggest water cooler topic of conversation.
What we know is that during an El Nino winter, the polar front jet and associated frontal systems take a more southerly track. This in theory results for more snow for southwestern Colorado. But we are really in the middle between moist and dry. And based on a study tracking such winters since 1976, we have had the equal amount of winters with above average snow and less than average snow.
So does a “super” El Nino take the storm track even farther south, leaving us in cold, dry air overall? I’ll dive into numbers later this summer.
Another plus is the fact that we will also have a westerly QBO set up for the winter of 2026/2027.
My forecast right now for Winter 2026/2027 is that it looks favorable for an average to above average winter.
If you would like to read more about the subjects I have discussed, I have included some links for your reading pleasure.
2021 Tucson, Arizona Monsoon Review
Review of the 2022 Monsoon Across the Southwest U.S.
Review of 2023 Monsoon Season in New Mexico
NWS Albuquerque Monsoon Highlight
– Arleen Prochazka
