Published Wednesday 2/3/21 at 8:50 am

This could be an interesting afternoon in the lower and mid-elevations. How about a chance for a thunderstorm after 2 pm? The high-resolution NAM model is showing exactly that. Montezuma County and La Plata County south of Rockwood have the best chance of seeing a thunderstorm this afternoon and into the early evening.  Most areas, especially below 8,000 feet, are going to see rain throughout the day. This evening snow levels will drop abruptly and there may be some brief heavy snow as the front descends through the area. The problem is that most of the precipitation will shut down as the front passes.

If you have been following for a while, you probably remember me referring to these types of setups as a “was that it?” storm. In the mid and lower elevations the temperature drops, the snow starts getting heavy, snow squalls develop, and you barely have time to even talk about it to anyone before it comes to an abrupt halt.

Above 8,500  feet the front does not pass as quickly so there may be enough time to accumulate a couple of inches. This is when most of the snow will accumulate at Purgatory. Depending on how much rain the lower and mid-elevation areas receive, this could turn into a flash-freezing event for portions of 160 and 550. If you are driving this evening over those highways keep an eye on the thermometer.

There is one other solution that may happen before the front passes through. We may get a period of westerly flow which would enhance precipitation in areas that favor that.

The High-Resolution NAM 3km model shows that happening this evening before the passage of the front.

The blues and yellow shades show the enhanced precipitation in eastern Montezuma and Dolores Counties as well the La Platas and the southwest quadrant of La Plata County. Portions of eastern Archuleta east of Bayfield benefit from the westerly flow as well as Telluride and Wolf Creek.

My biggest change in the past 24 hours is to reduce snow totals for Purgatory to 3 to 5 inches, which might be too optimistic, we’ll see.  Telluride and Ouray to Red Mountain should still see 6 to 9 inches of snow. Wolf Creek should not have any trouble accumulating 8 to 12 inches.

Any of the mid-elevations could see a couple of inches of snow later this evening. There may be a surprise or two from the westerly flow in the areas I outlined earlier. Lower elevations will probably only get a dusting to an inch.

I would love to hear any thunderstorm reports with rain or snow this afternoon and evening. Thanks for following and supporting the site!

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Published Tuesday 2/2/21 at 12:30 pm

Here is the latest Winter Weather Advisory. I think it covers the high elevations pretty well (>8,800 feet).

COZ018-019-030200-
/O.CON.KGJT.WW.Y.0008.210203T1300Z-210204T1600Z/
NORTHWEST SAN JUAN MOUNTAINS-SOUTHWEST SAN JUAN MOUNTAINS-
INCLUDING THE CITIES OF TELLURIDE, OURAY, LAKE CITY, SILVERTON,
RICO, AND HESPERUS
1029 AM MST TUE FEB 2 2021

…WINTER WEATHER ADVISORY REMAINS IN EFFECT FROM 6 AM WEDNESDAY TO 9 AM MST THURSDAY…

* WHAT…SNOW EXPECTED. TOTAL SNOW ACCUMULATIONS OF 4 TO 8 INCHES WITH LOCALLY HIGHER AMOUNTS. LESSER AMOUNTS BELOW 8000 FEET. HIGHER ELEVATIONS CAN EXPECT WINDS GUSTING AS HIGH AS 45 MPH.

* WHERE…NORTHWEST SAN JUAN MOUNTAINS AND SOUTHWEST SAN JUAN MOUNTAINS.

* WHEN…FROM 6 AM WEDNESDAY TO 9 AM MST THURSDAY.

* IMPACTS…TRAVEL COULD BE VERY DIFFICULT. AREAS OF BLOWING
SNOW WILL SIGNIFICANTLY REDUCE VISIBILITY AT TIMES.

There are still a lot of details to work out. Here is what I can tell you so far. Light snow showers should break out at or above 9,000 feet overnight into Wednesday morning. Light rain showers should start by late morning Wednesday across the lower and mid-elevation areas. The majority of the precipitation below 7,400 will fall as rain. There will be a brief period before the front rolls through Wednesday night where snow will fall in the mid-elevations, with a dusting by Thursday morning in the lower elevations.

Wolf Creek will accumulate the most snow, likely 9 to 12 inches by the time it is done. Telluride will have light accumulations until Wednesday evening, at the moment it looks like 8 to 10 inches by the end of Thursday. Friday night will bring another shot of snow to Telluride and Ouray. The biggest question at the moment is Purgatory. I am seeing model runs producing anywhere from 2 to 7 inches of snow.  Based on the southwest flow, and the burst of heavier snow with the arrival of the colder air Wednesday night, I am leaning towards the models that are producing heavier storm totals. For now, I am in the 5 to 8-inch camp but I may revise that tomorrow morning.

Here is what the Euro is putting out for totals liquid.

Yesterday, I talked about the pattern change that will leave most of the area high and dry for a while. I also mentioned that sometimes when the Polar Vortex drops into the Midwest and Great Lakes it eventually retrogrades west and flattens the ridge which allows moisture back into the western states. When this happens the combination of moisture and cold air can produce some amazing snow.

This was perfectly illustrated in the Euro’s morning run for day 10 which is the end of that model’s cycle.

Here is what that looks like. This is Friday, February 12th.

Here are the temps.

For forecasters, this is like ending an exciting movie 10 minutes before it’s over. Yes, it is 10 days away, but it will be an exciting time if the Euro continues in this direction.

Next Update Wednesday morning. Thanks for following and supporting the site!

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Published Monday 2/1/21 at 12:30 pm

I have been complaining about the models a lot lately. What looked like a series of storms and an extended period of stormy weather is now looking like a pattern change that would result in much of southwest Colorado being out of the storm track.

It is pretty normal to have poor model performance leading up to a major pattern change. We talked about the Stratospheric Warming Event some time ago and I said it can take a while for its effects to take place. It now looks like a ridge is going to build off the west coast all of the way up to the Gulf of Alaska. This is going to dislodge the Polar Vortex and it looks like it will eventually end up over the Upper Midwest and The Great Lakes Regions.

If this occurs, the storm track will ride up over the ridge and then down into Montana, Wyoming, and Eastern Colorado. This is less than ideal, but it does not mean it will be impossible to see some snow after this storm. The Northern and Central Mountains would be favored, but the Northwest San Juans can still get some snow. There are a couple of other scenarios that can come into play. Storms can come in under the ridge and result in snow across our area. The other scenario I like a lot better. This involves the Vortex retrograding west and flattening the ridge, which would pull the storm track into a favorable position.

At this point, it is too early to rule anything out. The models are showing the Vortex crushing the temps in Upper Midwest and Great Lakes State by next Sunday and Monday through Thursday the 11th.

Here are the overnight low temps in those areas for Monday morning. The cold will at least temporarily shift east throughout the week.

This far out, I feel like I am a bit in the weeds, but this would explain the problem with the models and their inconsistencies in dealing with the system coming in on Wednesday.

So let’s get back to that. The GFS and Euro flipped positions again overnight.

Here is the latest Euro

The Euro is showing deep southwest flow, especially setting up in Archuleta and Mineral Counties, which will transition into Northwest flow which will help out the Northwest San Juans.

The GFS

The GFS is showing weak southwest flow that quickly transitions to northwest flow.

The German ICON

Of all of the model runs I have looked at, the German model makes less sense than any other. Rarely if ever have I seen a precipitation pattern that ends up like this.

Whatever happens, we will take what we can get. I am not concerned with the pattern change. In January 2019, we entered a dry pattern that started on the 19th and lasted until February 5th. Then, in February 2019 we set all-time records for snowfall all across the area.

Next Update Tuesday, thanks for following and supporting the page!

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Published Sunday 1/31/21 at Noon

The GFS and Euro are getting a little closer with their precipitation forecasts but they are still apart on the details. They basically went in different directions this morning. The GFS was lighter with precipitation but has now nudged up its totals. The Euro has been more bullish on precipitation and it has now backed off its totals. The Canadian is so far off I can’t use it right now.

Here are the current precipitation forecasts, but these are not set in stone by any means.

GFS

Euro

One thing that is becoming increasingly clear is that with the exception of the resorts this could start off as a sloppy messy mix for many areas below 8,000 feet.  It is too early to sort out the exact rain/snow/mix elevations because the models will likely change between now and then.

Temps will warm to above average Monday and Tuesday in advance of the front. The winds will pick up with the tightened pressure gradient.

The storm track is still uncertain but as the storm pushes onshore tomorrow afternoon and evening, the models should be able to lock on to it a little better.

Next Update Monday, thanks for following and supporting the site!

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Published Saturday 1/30/21 at 7:45 am

I have not heard from a lot of people this morning. It looks like there were no surprises. Telluride did get some help with the wind change, last I saw they had 8 inches. Purgatory ended up with 5 inches, and the last report from Wolf Creek was 10 inches. The low elevations I have heard from had mostly a dusting. Mid-elevation reports of 2 to 4 inches have been common.

The models are still trying to figure out next week. They are slowing the first system’s arrival until some time on Wednesday. They are in agreement that there is going to be a period of unsettled weather from Wednesday through the weekend (perhaps longer). They do not agree if it will be one big storm, two pieces of a big storm that come through at different times, or two separate storms. There is a lot to work out yet.

When I look at the forecast for the MJO, the Euro and the GFS model take us straight back to where we were from the 22nd to the 26th, which would indicate similar conditions to what we experienced last weekend and the first of the week.

Looking beyond next weekend (and I am not sure why I am), there are indications that another storm will settle in around the 9th. If you have to do any snow removal mitigation, today through Tuesday will be a good time.

Next Update Sunday afternoon, thanks for following and supporting the site!

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Published at  12:45 pm 1 Friday 1/29/21

The biggest change in the last 24 hours has been a couple of the models producing higher amounts of precipitation for Telluride, Ouray, Silverton, and Wolf Creek.

A winter weather advisory has been issued for sub-advisory snow. In other words, as I explained a few days ago, they bent the rules to issue the advisory. Here it is:

NATIONAL WEATHER SERVICE GRAND JUNCTION CO
333 AM MST FRI JAN 29 2021

COZ019-292200-
/O.NEW.KGJT.WW.Y.0007.210130T0000Z-210130T1500Z/
SOUTHWEST SAN JUAN MOUNTAINS-
INCLUDING THE CITIES OF SILVERTON, RICO, AND HESPERUS
333 AM MST FRI JAN 29 2021

…WINTER WEATHER ADVISORY IN EFFECT FROM 5 PM THIS AFTERNOON TO 8 AM MST SATURDAY…

* WHAT…SNOW EXPECTED. TOTAL SNOW ACCUMULATIONS OF 4 TO 8 INCHES WITH LOCALLY HIGHER AMOUNTS ABOVE 9000 FEET. WINDS GUSTING AS HIGH AS 40 MPH.

* WHERE…SOUTHWEST SAN JUAN MOUNTAINS.

* WHEN…FROM 5 PM THIS AFTERNOON TO 8 AM MST SATURDAY.

* IMPACTS…TRAVEL COULD BE VERY DIFFICULT, ESPECIALLY OVER
MOUNTAIN PASSES.

I would be very surprised if Telluride and Ouray are not added to the advisory.  As the storm departs winds will change to a more favorable flow for the Northwest San Juans. There should enough moisture leftover to develop some heavier snow showers in those areas Saturday morning.

The German ICON model picked up on this yesterday, the other models picked up on it this morning.

Here are the latest model runs I am using for my forecast.

Euro

GFS

German

NAM 3km

Here is the current (noon) surface map showing the system heading our way from western Utah.

High mountain snow showers are possible this afternoon, the heaviest snow in all areas should start after 9 pm (hopefully, later than that).

Here is the animated future radar beginning at 5 pm this evening, ending at 1 pm Saturday. The blue is snow, the darker the blue, the heavier the snow.

The forecast is a little tricky for low elevations because of temperatures. But here is what I have.

Cortez, Farmington, Aztec 0 to 2 inches.

Durango, Mancos, Bayfield 1 to 3 inches.

Mid-elevations 2 to 5 inches, higher amounts are possible above 7,800 feet.

Pagosa 3 to 6 inches.

Purgatory 4 to 7 inches.

Telluride, Ouray, Silverton, Mayday 5 to 9 inches.

Wolf Creek 8 to 12 inches.

The models are still trying to work out the details on the next storm which should arrive very late Tuesday or early Wednesday. The Euro is showing a decent event setting up, the other models have not yet completely embraced the situation.

Next Update Saturday morning, unless something comes up before that. Thanks for following and supporting the page!

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Published at 12:15 pm Thursday 1/28/21

On Friday the front associated with the atmospheric river (AR) event in California will move into Nevada, then Arizona and Utah. Mammoth Mountain will end up with about 7 feet of new snow at the base and 9 feet at the summit from this storm cycle.

Interestingly enough, AR events like this are rated on a scale of 1 to 5, based on duration and moisture transport. This event is rated a 2…

As I said over the weekend, it is rare for these AR events to deliver big moisture to our area, we will likely only be getting a couple to a few inches of snow Friday night into Saturday. Then the storm will move east, reload, and then strengthen with moisture drawn up from the Gulf of Mexico as it makes its way into the midwest.

Aside from a few flurries Friday morning from Purgatory northward, the main precipitation bands should not hit the forecast area until early Friday evening. If you are at 6,500 feet or lower, you will want the precipitation to arrive a little later (around 8 pm) if you want it to all fall as snow. The snow should wrap and move quickly Saturday morning.

All said and done, I am expecting 1 to 3 inches across the lower elevations. 3 to 6 inches are likely across the mid-elevations, with  4 to 8 for Purgatory, Mayday, and Telluride. Wolf Creek should be able to accumulate 8 to 12 inches. I will dial this in a little better Friday afternoon.

Here are the latest model runs for this storm. There was a problem with the Canadian model this morning so I don’t have that data.

Euro

GFS

German

The German is a believable outlier. What I mean by that is the model is suggesting a more westerly flow towards the end of the storm. This results in higher totals for areas that favor westerly flow. I can’t count that out. Another 24 hours should allow the models to come together on a more cohesive solution. I would be very encouraged if I woke up to higher model totals tomorrow morning.

The next system will be wetter but slightly warmer. It should arrive late Tuesday or early Wednesday. Models are in agreement that this will be a bigger precipitation producer than Friday night’s storm, but they differ on how much will fall in the lower elevations. At the moment the Euro is more bullish. That storm should wrap up on Thursday, but I am already seeing another storm coming in Friday the 5th for the weekend.

Next Update Friday afternoon, thanks for following and supporting the site!

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Published at 12:14 pm Tuesday 1/26/21

That was a fun 8 days! Several locations got decent snow. Purgatory caught up and slightly surpassed Telluride for the season. Wolf Creek will end up 5  1/2 feet or more over that same time period.

A couple of the morning models were suggesting additional snow today at all elevations. The surface front has passed Durango and is stretched across northeast La Plata County, just southwest of Purgatory, and is responsible for an uptick in snow across areas north of Durango.  The front is moving very slowly because there is another front just to the southwest of Pueblo and the Front Range. To our southwest, snow continues in Arizona and there is another piece of energy northeast of Flagstaff.

While I am not holding my breath for additional snow in elevations below 8,000 feet, there are a lot of opportunities for the snow to redevelop so I can’t exactly rule anything out.

The AR will arrive in California later today and will ring out several feet of snow over the Sierra by Friday. A small piece of it will drift our way by Friday evening. I do not expect anything significant, it will be a very low impact storm. It will be more significant for northern Arizona and southern Utah than our area.

Beyond that, it looks like a birthday storm will be a better bet next week for us. That storm looks to come in very late on Tuesday the 2nd through Thursday the 4th. For whatever reason, since I moved here 13 years ago, storms seem to arrive within a day or so of my birthday which is the 4th.

Thanks for all of the reports, it helps more than most people realize. If anyone in the lower or middle elevations west of 550 sees snow picking back up this afternoon, let me know. My next Update will be Thursday afternoon. Thanks for following and supporting the site.

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Published Tuesday 1/26/21 at 6 am.

If the overnight high-resolution model is correct, we still have some snow to fall before this winds down. Several lulls throughout the night were accurately predicted by that model so I will see where this takes us.

Keep those reports coming!

Next Update later today…

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Published 1/25/21 Monday at 1:30 pm

Sometimes, you have to trust your gut instinct. Sometimes you’re right, sometimes you’re wrong, ask Matt LaFleur. If I am wrong I will have a couple of days to figure out where I went wrong before I prepare for the weekend storm forecast.

I have been complaining lately that the models are under forecasting some of the precipitation amounts. That does seem to be the case again this morning with the GFS, the Canadian, and the German models. However, I am seeing some higher amounts and similarities between the morning run of the high-resolution NAM 3km model and the latest European model run.

My forecast is going to be based on those two models plus the conditions this evening and overnight into tomorrow morning. Basically, the conditions are going to be perfect for snow production. A little can become a lot.

As of the time that I am writing this (11 am), there have been no changes to the Winter Weather Advisories. Which reminds me, I have heard from a few people who want to know why Winter Weather Advisories are being issued instead of Winter Storm Warnings.

The first thing that you have to know is that the rules for choosing one of these winter highlights over another are pretty loose and up for interpretation. They also vary based on geographic location. If we get two inches of snow there may be no highlights issued. If Florida or Georgia get two inches of snow they would likely issue a Winter Storm Warning.  The general rules depend on the amount of snow expected. But other factors include wind, ice or freezing rain and holiday travel, and the time of year.

In Colorado, the general rule is that a Winter Weather Advisory is issued if 3 to 6 inches of snow is expected below 8,000 feet. If 6 to 12+ inches are expected below 8,000 feet a Winter Storm Warning is issued. Above 8,000 feet, if 6 to 12 inches are expected a Winter Weather Advisory is issued. If more than 12 inches is expected a Winter Storm Warning is issued. As I said, the NWS forecaster has the option of taking other things into consideration before deciding which product to choose.

Here is the storm on the surface map. It is likely further east than this by now. But check out some of those temperatures in Southern California and Arizona, like Lake Havasu at 46 degrees!

Here are the precipitation maps.

Euro

NAM 3km

Pre-frontal precipitation could start falling by sunset but the more meaningful snow won’t get going until around midnight. The snow will continue through the night and the morning commute will be pretty ugly. Any remaining melted snow on the roads this afternoon will freeze very quickly this evening so some areas will likely have a layer of ice under the snow in the morning. The snow should stop from south to north around or after 11 am. The temperature in most areas will struggle to get into the 20s tomorrow with many areas staying in the teens.

Here are my forecast totals for tonight through late day on Tuesday:

Aztec, Bloomington, Farmington  1 to 3 inches.

Ridgway 2 to 4 inches

Telluride, Ouray, Silverton (town) 3 to 6 inches.

Cortez, Ignacio, Mancos, Bayfield (at 160) 3 to 6 inches

Durango in town, Pagosa in town 5 to 8 inches.

Mid-elevation areas 7 to 12 inches higher totals possible above 7,700 feet.

Mayday, Purgatory and Wolf Creek 8 to 13 inches.

I know that these are in some cases considerably higher totals than you are seeing anywhere else but there is a method behind the madness, as I described in the first part of the post.

If there are any major changes from the NWS in their afternoon forecast package I will comment. Otherwise, the next Update will be Tuesday morning early.

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