Still On Track!

12/4/21 Saturday 7 am

Another 24 hours of exciting model runs! I will get to that in a minute…

I was reading an interesting (if you are a complete nerd like me) article from a weather service I subscribe to about the coming cold from mid-December into January. The writer researched years that were similar climatologically in the past. These are referred to as analog years. I took those years and did a little research of my own.

There were 9 winters that he came up with that I could find data on. I looked at those winters for our forecast area and was very pleased with what I saw.

In Durango, four of those years were average snowfall years. Two were below average. Two were above average. Of those two above years, one was the all-time record snowfall year of 1978-79.

In Telluride, there were two average snowfall years. Two were below average. Five were above years. Of those five, one was the third snowiest on record. The other was the fourth snowiest on record.

Here is the raw data output from the Euro extended model showing the average temperature anomalies (negative) starting December 15th ending January 16th.

The model is showing daily temperature composites in our forecast area averaging 3 to 5 degrees below normal for the 32 day period!

As I mentioned earlier, the models are still on board for a significant storm later next week. The little system coming through late Monday into Tuesday is not going to be a big deal. It may be a little bit of a nuisance over the passes, but overall nothing to get excited about.

Here are the latest model runs showing the precipitation mainly from the storm late next week. The Euro is still unusually stingy compared to the other two models.

GFS latest run liquid equivalent

GFS latest run snowfall at 10-1 ratio

GFS previous run 10-1 snowfall

Canadian model latest run liquid equivalent

Canadian snowfall at 10-1 ratio

Canadian previous run snowfall at 10-1 ratio

Latest Euro liquid equivalent

Euro latest snowfall 10-1 ratio

Euro previous snowfall 10-1 ratio

The last two runs of the Euro still look good for mid and higher elevation areas, but not quite as much fun for the lower elevations of the southern forecast area.

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Winter Is On The Way

12/3/21 Friday 9:00 am

It is difficult not to get excited about the model runs. Especially the GFS and Canadian models along with their ensemble members.

I have often written about model biases. The two biases that always jump off the screen are the Euro and GFS’s bias in failing to detect cold after about 7 days. The other biases are that the GFS moves storms too quickly from west to east, while the Euro tends to overdevelop a storm in the west and move it too slowly to the east.

That is what makes these model runs (48+ hours worth) for the GFS and Canadian so intriguing. The GFS is acting outside of its normal bias pattern. That does not mean it is right, we will have to see. What is very encouraging is the agreement among ensemble members and how it continues into the GFS long-term extended model. The same situation applies to the Canadian model.

We are still 7 days out from what could be a very big storm for the area. That is why I am trying to not get too excited and get everyone’s hopes up. The consistency in the GFS and Canadian, as well as their respective ensemble model (family) members, is nearly too good to be true.

It is certainly not unheard of, we have had big mid-December storms in the past. I think it is the anomalously dry and warm conditions that we have been experiencing lately that are giving me the “too good to be true” mentality.

Late Monday through Tuesday a storm will drop down from the north and leave a bit of snow, especially for northern portions of the forecast area. A couple of inches of snow up to half a foot could accumulate. The lower elevations will likely see a few drops of rain or light rain and snow mix.

The GFS and Canadian show a very potent storm beginning either late Thursday or early Friday. The latest runs are showing heavy snow across the area that eventually will move out of the area late Saturday. The Euro shows the storm but has been inconsistent from run to run with the storm track and the amount of snow.

Here are the liquid precipitation and snow forecasts from the various models. These totals reflect both storms. Starting on Sunday I will be able to add a couple of more models which have shorter run times to the mix. If these are correct, the snow totals above 8,000 feet could be 20 to30 percent higher than what the models show.

GFS liquid

GFS snow

Canadian liquid

Canadian snow

Euro liquid

Euro snow

Previous Euro run liquid

Previous Euro run snow

You can see the Euro is not calling for a miss, it is just not as enthusiastic as the other two models. Given our current situation, if we were only looking at the Euro we would still be excited about this storm. But given the other two model runs, I have become snow greedy.

The long term still looks great.

Here are the (positive) forecasted precipitation anomalies for the long term. These maps display how much liquid precipitation is being forecasted (above average) by the models.

GFS 35 days outlook

Canadian 32 day outlook

Euro 46 day outlook

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Big Changes On The Way!

12/2/21 Thursday 6:35 am

I really like what I am seeing in all of the recent model runs. But before I get started, I have been meaning to share something fun with all of you Snow Lovers.

I spend a lot of time looking back over historical records and occasionally come across something that leads me in a different direction. That happened not too long ago. I was looking at record snowfalls of the past and I ended up looking at the pacific northwest.

Mt. Baker ski area is a small ski area (by Colorado standards) in the northern Cascades not too far from the Canadian border. They are known for the amount of snow they get per year. They have had three 1000+ inch seasons in roughly the last 50 years. They average over 660 inches of snow per year. They set a record for snow during the 1998-1999 season: 1,140 inches (95 feet)! This was verified by NOAA.

Here was their snow stake that season.

Here it is in the summer.

They closed multiple times that season to clear snow from under the lifts. Here was their mid-mountain loading station.

Here is how it looked in the summer.

Is that fun or what?

By the way, that was not a good snowfall year for the southern portions of our forecast area. We accumulated only 60% of our average snowfall. Northern portions of the forecast area received average snowfall for the season.

As I teased earlier, I like what I am seeing in the models. In my last post, I mentioned the storm around the 7th.  I have not been very excited about it because the models have not been too consistent on the storm track or the amount of cold air.

Recently, some of the model runs have shown a classic northwest flow set-up that blanks the southern and central portions of the forecast area. Other times, it shows a more southerly track that benefits the south and misses the north. Here is the latest run of the GFS showing a favorable southern track.

Here is what it looked like 12 hours earlier.

The latest Euro supports the northerly track. The Canadian looks like a blend of the Euro and GFS.

What really has my interest is another storm at the end of next week. The timing is uncertain at this point. Some of the model runs are showing a small system coming through on Thursday followed by a bigger system, or a reinforcing shot on Friday through Saturday or Sunday. Others have shown nothing until Friday.

I talk a lot during the winter about models being right for the wrong reason. This just means that the models may be wrong about which storm brings the most snow. It could also mean that the models may be wrong about when the storms start or stop. But if you look at the total amount of snow or liquid precipitation forecasted over the extended 7 to 10 day period, they end up fairly accurate.

Here are the total liquid and snow forecasts for Euro, GFS, and Canadian models. The Euro and Canadian move the storm out of our area by late Saturday. The GFS keeps things cranking through the day on Sunday.

Euro liquid

Euro snow

GFS liquid

GFS snow

Canadian liquid

Canadian snow (likely too enthusiastic)

But fun to look at…

Here is the latest MJO forecast from the GFS ensembles.

This correlates well with the storms. It shows the MJO entering low magnitude phase 7 on Tuesday and higher magnitude phase 7 on Friday.

My next update will be Friday morning. I will discuss the extended outlook. Thanks for following and supporting the site!

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Understanding The MJO

November 30, 2021

In the winter the effects of the MJO are more pronounced in the United States. I have not talked about it for a while, so here is a refresher for some and a (relatively) brief explanation for new followers.

I am going to do my best to keep this as easy to understand as possible, and as unboring as possible.

The MJO is short for Madden Julian Oscillation. Yes, it was discovered by a guy named Madden and a guy named Julian in the early 70s. The MJO is a mostly eastward-moving tropical disturbance that circles the planet through the tropical latitudes about every 60 days or so.

Forecasters refer to the location that the tropical disturbance (the MJO) is in as a phase. There are 8 phases of the MJO.  Different phases at different times of the year can contribute to the weather across the planet. In the United States, the biggest effect on the weather occurs in (roughly) October through April. The winter months are impacted the most.

Here is the latest GFS forecast for the MJO.

It sometimes helps when you see this for the first time to consider this the earth. I know it is a square but it helped me to understand it better years ago when I first saw this.

The numbers 1 through 8 refer to the particular phases (locations) of the MJO. The red squiggly lines which, in this case, travel from phase 1 to phase 5 are the past 40 days of where the MJO has been.

The green lines are where the GFS ensemble model is forecasting the MJO to go. The yellow lines are where the individual GFS ensemble family members are forecasting the MJO to go. The green lines are the average of all of the yellow lines. The fat green line is week 1, the skinny green line is week 2.

On the left side of the diagram you see the numbers o through 4 on top, and through -4 on the bottom. These represent the magnitude of the particular phase. The circle in the middle lines up with number 1  (-1). This is considered the “null” phase. This means the effects of the MJO will be minimal.

Once you get out of that circle you approach the higher magnitudes of a particular phase reaching 2 (-2) or beyond.  You can expect some extreme weather events when you reach the higher magnitudes of 3 (-3) and 4 (-4)

As I said different phases have different implications at different times of the year. I don’t have all of the implications of all the phases at all times of year memorized, I have a chart I refer to.  Here is the best thing to remember.  Phase 1 and 2 in the winter months usually indicate below-average temperatures and above-average precipitation for our area. Phases 7 and 8 usually imply slightly below-average temperatures and average precipitation. Phase 6 is warm in early winter for most of the United States.

So what is the forecast showing us? Straight into the heart of phase 6 until December 7th.

Here is what phase 6 looks like.

Here are forecasted temperature anomalies for the next 7 days.

GFS

Hopefully, we will make a short trip through phases 6 and 7 and end up in 8, 1, 2 from late December through February!

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December Update

Tuesday 11/30/21 4:25 am

I was up most of the night working on a refresher explanation of the MJO. I have gotten a few emails from long-term followers about it and I have a ton of new followers so I thought it was overdue. I will be posting that discussion mid-morning. You may want to read it because I will be referring to the MJO a lot over the next few weeks. It appears we may be going into some favorable winter phases after mid-December!

Over the last couple of days, some of the ensemble models and a few operational runs have been trying to sneak in a little storm around next Tuesday, December 7th. But that is just what it is, a little warm storm.

In my last post, I was focusing on two dates, the 9th, and the 12th. I have not changed my mind. I still think it will be around the 12th before cooler air starts working into the picture.

Here are the latest maps from the extended ensemble runs of the Euro and GFS.

Euro liquid-equivalent forecast through December 11th.

GFS liquid-equivalent forecast through December 11th.

Pretty similar…

Euro liquid forecast through December 31st

GFS liquid forecast through December 31st

For snow, the Euro extended model gives me a 32-day parameter and a 46-day parameter. The GFS extended model gives me a 35-day parameter. It is also important to keep in mind that the models are locked into a 10 to 1 snow to liquid ratio. Towards the end of December, we should be between a 12 to 20-1 snow to liquid ratio.

The other thing to keep in mind is that many of the extended models have a warm forecast bias and they usually verify cooler for the period they are forecasting for.

Euro snow through December 30th

Euro snow through January 13th

GFS snow through January 2nd

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December Outlook

11/27/21 Saturday 9:40 am

The next 12 or so days are going to have people wondering where winter is.  Especially all of the new residents who moved here since Covid. Those of us who have lived here for a while know that for the most part, winter does not usually get going until mid to late December.

I have the distinct advantage of being able to look at the long-term weather models. There is good agreement right now that we will start to transition into a wetter pattern after December 9th. The longer-term Euro weekly model and GFS extended model concur and they then show us entering a cooler and wetter pattern beginning around December 12th.

The model shows that pattern continuing for the duration of the run which concludes January 9th (Euro). To clarify, that is the end of the model run, not necessarily the end of the cooler wetter pattern. What is significant about this is that even with the first 12 days of the model runs showing basically ZERO precipitation, we end up with average precipitation for the lower elevations with above-average precipitation in the mid-and higher elevation areas.

The ridge should have a dominant hold on our weather for the foreseeable future. The transition that occurs is that the ridge begins to flatten out. This opens up the storm track, but it will take a few days before we see cold working its way down to the Western United States.

There is still some speculation out there that the cold may be in response to a stratospheric warming event that is coming. Stratospheric warming events often lead to the displacement or split of the polar vortex–a term we get used to hearing about in the winter. The polar vortex is nothing more than the low pressure that keeps our polar regions cold.

Stratospheric warming events often displace the polar vortex and drop it further south in the northern hemisphere. Determining where it will end up is tricky.

In December 1967, after a stratospheric warming event, extremely cold air led to snow in La Jolla, California. The cold air and storm track moved onshore and led to the biggest snowfall in history for Flagstaff and other areas of northern Arizona. Snow fell for 8 days. Flagstaff received 86 inches of snow during that period. Over 100 inches fell in some mountain locations. The storm tracked east into New Mexico and it was one of their worst winter disasters ever.

Colorado did not escape the storm, although the impacts were not as great/severe. The only storm data I have on it was that Grand Junction received 16 inches of snow during that storm. I do know that Durango reported 46 inches of snow for the month of December. Rico reported 62 inches of snow for the month. The towns of Telluride and Silverton both reported 45 inches of snow for the month, but I am not sure how much of it was attributed to this storm.

I forgot to mention the date all of this occurred: December 12th, 1967 through December 20th, 1967…

By the way, did you hear that Antarctica had its coldest winter on record this year? The average temperature at the South Pole during polar darkness (April through September) was -77 degrees. It was attributed to a stronger than usual polar vortex.

Time to look at some precipitation maps.

As I said, nothing to talk about between now and December 8th.

GFS ensembles mean through December 7th.

GFS extended ensembles mean December 7th through December 30th.

Euro ensembles mean through December 7th.

Euro extended model December 7th through December 31st.

The Euro extend model has a longer forecast period. Here is the projection for December 7th through January 9th.

Euro extended snowfall December 7th through December 26th.

Euro extended snowfall December 7th through January 9th.

My next update will be Tuesday, November 30th-unless I see something cool before that. Thanks for following and supporting the site!

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Happy Thanksgiving

11/25/21 Thursday 5:30 am

I hope everyone has a nice Thanksgiving day! I am very thankful to live in a wonderful area and humbled and grateful to have as many followers as I do in our small bubble of Southwest Colorado.

Our patience is going to be tried again over the next 10 to 14 days as the persistent ridge builds back in over the area. There are signs that colder air will infiltrate the western United States around or after the 10th.

Don’t be too concerned about the lack of snow for November. I looked back over the years and I noticed in November 2001 Durango received nearly 15 inches of snow. For the remainder of the winter, they only accumulated another 20 inches. In contrast, in November 2009 Durango received 0.80 inches of snow during the month but had another 97 inches throughout the winter!  These are just two examples but I could go on and on.

I will break down the latest long-term Euro weekly run on my next update which will be on Saturday morning. That will give us a 6-week glance into the future.

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A Mid-Elevation Miss

No big surprises last night. Resorts hit the lower end of my expectations as warmer air worked into the area and the bulk of the precip missed us to the south.

It appears that Telluride is upgrading their webcams. I was able to get through once on their website and it looked like a little over 3 inches on the snow stake. Purgatory reported 3 inches, the snow stake says 4 inches, and I got 3 reports of over 4 inches just south of Purgatory. I also got a report of 4 inches in Rico as of 4 am and it was still snowing. A little lower, I got a report of 2.5 inches at Haviland.

The clouds and fog should clear later today. It will be chilly early tomorrow morning. Mid-and lower elevations may fall into the teens with single digits above 8,500 feet. The ridge is going to build back into the area for a while. I will talk more about that in my update tomorrow morning.

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Tuesday Afternoon Update

11/23/21 Tuesday 3:15 pm

My update is a little later than normal today because I had to finish up the last-minute Thanksgiving shopping. Hopefully, everyone is finished with their shopping because it was pretty crazy today. Here are a couple of highlights from today then I will move on to the weather. City Market north is out of mushrooms and low on fresh herbs. Albertsons decided it would be a good idea to reset their cheese wall. There is no cheese there at all, I was informed that there was “some” cheese in a cooler near the roses… I went to Speedway on 160 to fulfill my promise of washing my car. I didn’t just get the cheap one either. While there, I witnessed a woman driving away from the pump with the gas nozzle still attached-she ripped it right off the pump, hose included. To her credit, she did go in and tell the attendant. If you have to go out tomorrow, good luck!

Right on cue, the snow levels started lowering earlier this afternoon. Snow is currently accumulating on the 550 passes. It is starting to mist at my house at 7,450 feet. The atmosphere is moistening up nicely.

As far as the models go, the high-resolution models are still showing the potential for some upside surprises. The models are suggesting that the SW low will merge with the NW trough and cold front, how and when that happens could lead to a variety of results.

I think a safe forecast is 2 to 5 inches of snow between 7,400 feet and 8,200 feet. 3 to 6 inches of snow above 8,500 feet. 0 to 2 inches of snow between 6,500 and 7,200 feet. I won’t rule out some upside surprises for the resorts, Mayday, and CR 240 areas above 8,000 feet.

My next update will be Wednesday morning. Thanks for following and supporting the site!

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Tuesday Morning Update

11/23/21 Tuesday 9 am

Moisture is streaming into the upper levels of the atmosphere ahead of the main weather maker for our forecast area that is currently in Western Arizona.

The NWS did not feel that advisories would be needed for this system so they issued a SWS (Special Weather Statement) due to increased travel for the holiday.

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
150 AM MST TUE NOV 23 2021

COZ010-018-019-240000-
GORE AND ELK MOUNTAINS/CENTRAL MOUNTAIN VALLEYS-
NORTHWEST SAN JUAN MOUNTAINS-SOUTHWEST SAN JUAN MOUNTAINS-
INCLUDING THE CITIES OF ASPEN, VAIL, SNOWMASS, TELLURIDE, OURAY,
LAKE CITY, SILVERTON, RICO, AND HESPERUS
150 AM MST TUE NOV 23 2021

…SOME SLICK ROADS POSSIBLE OVER THE SAN JUANS AND VAIL PASS
TUESDAY NIGHT THROUGH WEDNESDAY MORNING…

A WEAK SYSTEM WILL MOVE ACROSS WESTERN COLORADO TUESDAY EVENING THROUGH WEDNESDAY BRINGING SNOWFALL TO HIGHER ELEVATIONS. WHILE AMOUNTS ARE SUB-ADVISORY, 2 TO 4 INCHES LOOKS POSSIBLE ALONG THE 550 CORRIDOR THROUGH THE SAN JUANS WHILE 1 TO MAYBE 2 INCHES IS EXPECTED ON I-70 HEADING EAST FROM VAIL UP TO VAIL PASS.

IF YOU’RE PLANNING ON TRAVELLING THROUGH THESE AREAS TUESDAY NIGHT INTO WEDNESDAY MORNING, PLEASE BE AWARE OF THE INCREASED CHANCES FOR SNOWY AND SLUSHY ROADS. GIVE YOURSELF SOME EXTRA TIME TO REACH YOUR DESTINATION AND REMEMBER TO SLOW DOWN.

All of the models have sped up the onset of precipitation. They are suggesting that the higher elevation areas could see snow showers starting around 2 pm, we’ll see. The models are also showing light showers developing across mid and lower elevation areas late this afternoon or early evening.  Light rain should change over to snow later tonight.

The lower and medium-resolution models are suggesting snowfall totals that would resemble the amounts in the SWS (2 to 4 inches).

Here are the last two latest runs from the European model.

Latest liquid equivalent

Latest snow

6 hours earlier liquid equivalent

6 hours earlier snow

The latest high-resolution NAM 3 km model is showing some higher totals in certain orographically favored areas.

Liquid equivalent

Snow

The high-resolution model run looks a lot more interesting!

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