Saturday Update #1

Not a lot of change overnight in the models, the current consensus is a 2 pm to 5 pm start time depending on your location. All snow above 8,500′ at that time, rain below 8,200′ slushy rain-dominated mix between 8,200′-8,400′. I never like to use overnight runs for totals so let’s wait on that until the next update in a few hours. That being said, I think Purgatory and Telluride will definitely be on the lower side of the 6-12″ advisory. Wolf Creek still has a chance at double digits.

As far as Sunday travel goes, locally most models are trying to pick up on a band of brief moderate snow sometime between 8 am-11 am west of 550 along or south of the 160 corridor, but I don’t have a lot of confidence on that yet. For those driving back from Denver the main lower resolution models are picking up on some moderate snow between 8 am-11 am in western Park and Chaffee Counties, but the higher resolution models have that precipitation further east. What I don’t see is unusually high wind speeds that would lead to closures. When people ask me about driving conditions, I always have to ask people what their comfort level is. With all of the new residents in Colorado, some are very risk-averse, “if it’s snowing-we aren’t going”. But most long time Colorado residents and visitors are familiar with normal winter driving conditions, which is what I expect on Sunday. Next update around Noon today.

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Widespread Weekend Precipitation Event

The closed area of low pressure that is going to responsible for precipitation this weekend is still off the coast of Southern California. You know what that means–it is difficult to have a great deal of confidence on stormtrack until it not only gets onshore but safely makes it into Arizona. When I look at its current location it makes me wonder if the models are too fast with the onset of precipitation tomorrow. At the moment there is good agreement that that snow will start mid to late afternoon in the higher elevations (8,500+), with rain below 8,000 starting after dark. Just because they all agree, doesn’t make it so. We will see.

Using that model guidance the heaviest rain and snow would fall very late Saturday night and Sunday after midnight through late morning Sunday. I am going to have to follow up with that first thing Saturday morning so stay tuned for that.

I sense that a lot of people living below 8,500′ elevation like me, at this point, just want the moisture in whatever form it might be. If the Ski Resorts can pick up moderate to heavy snow and everyone else picks up decent rain, that would be a big win.

The GFS is leading the way with the highest totals. Thursday evening and overnight last night the GFS and Canadian were pretty close to the Euro. But then this morning happened and both models have gone a bit off the rails cranking up the totals into possibly a great wishcast.

As much as I would like to believe what they are selling until I see the Euro jump on board they look a bit dubious and overpromising to me. Why you ask? The latest skills test that came out this week still shows the Euro leading in accuracy, with the Canadian coming in second while the GFS is in third place. They are not graded on precipitation amounts but rather the 500 MB trough position which basically dictates the storm track.

As the trough passes, wherever that may be, snow could lower to at least 6,500 feet Sunday morning, at that point most of the precipitation should be leaving the area, so we may see a little bit of snow in the lower elevations, but more importantly, I will be watching the potential for flash freezing early Sunday morning near sunrise to 8 am in mid and lower elevations of the 160 and 550 corridors–hint CDOT…

So what can we expect? Since most of us will be seeing liquid precip I will share that with the snow amounts from each of the 3 main models. Tomorrow I will update this so don’t take it to the bank yet. I am never comfortable with the higher resolution models until the day of the storm so I will also highlight those tomorrow morning. Wolf Creek could do very well with this event. I have had a number of emails and comments about travel from Denver on Sunday, I will talk more about travel concerns after the model highlights.

Here are the GFS’ liquid totals, again, wait to get too excited about this.

gfs-deterministic-colorado-total_precip_inch-2513200

GFS snow

gfs-deterministic-colorado-total_snow_10to1-2513200

Canadian liquid

gem-all-colorado-total_precip_inch-2513200

Canadian snow

gem-all-colorado-total_snow_10to1-2513200

Euro liquid

ecmwf-deterministic-colorado-total_precip_inch-2513200

Euro snow

ecmwf-deterministic-colorado-total_snow_10to1-2513200

As far as traveling goes, you can see just by the totals throughout the state that there are some differences in the storm track. Here are a couple of snapshots from the Euro for Sunday morning. Remember the lightest blue is light snow, medium blue is moderate and the darkest blues are heavy snow.

Euro 5am Sunday

euro5 am

Euro 8am Sunday

eurosunday 8am

Euro 11 am Sunday

euro 11am

Euro 2 pm Sunday

euro 2pm

That heavy band above is over Colorado Springs and El Paso County.

Euro 5 pmeuro 5pm

Make sure you check back throughout the day tomorrow because as the afternoon short term models come in I am seeing some differences in the storm track that could lead to higher totals in some areas (if correct).

I will have an update around 7 am tomorrow, the next by 2 pm. There is still time to get your cars washed before this all starts! Thanks for following.

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Advisory Issued

I am back. I was a little under the weather yesterday, no pun intended. We do have something to talk about and we will. I will start breaking the whole thing down after the morning suite of models comes out. All moisture is good moisture!

Here is the introductory Winter Weather Advisory.

SOUTHWEST SAN JUAN MOUNTAINS-
INCLUDING THE CITIES OF SILVERTON AND RICO
322 AM MST FRI FEB 21 2020

…WINTER WEATHER ADVISORY IN EFFECT FROM NOON SATURDAY TO 3 PM
MST SUNDAY ABOVE 8500 FEET…

* WHAT…TOTAL SNOW ACCUMULATIONS OF 6 TO 12 INCHES ABOVE 8500
FEET WITH LOCALLY HIGHER AMOUNTS UP TO 18 INCHES ON THE HIGH
PEAKS AND LESSER AMOUNTS IN LOWER ELEVATIONS.

* WHERE…SOUTHWEST SAN JUAN MOUNTAINS.

* WHEN…FROM NOON SATURDAY TO 3 PM MST SUNDAY.

* IMPACTS…PLAN ON SLIPPERY ROAD CONDITIONS. PATCHY BLOWING SNOW
COULD REDUCE VISIBILITY AT TIMES.

There are still some model differences as to where the heaviest precip will accumulate. There is very good agreement, however, that the precipitation will move into the general area between 2 pm and 6 pm on Saturday and wrap up late Sunday. I will be updating this afternoon, then a couple times on Saturday and Sunday.

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Maybe Something To Talk About

There has not been a lot to talk about this month, I have a difficult time getting too excited about tomorrow, I have said more than once that it is improbable to get significant snow from a small short wave trough retrograding from eastern Colorado over the divide then producing snow in western Colorado.

I think the GFS has a realistic outlook for the Wednesday event, it looks very similar to all of the other models.

gfswed

Does that look like something worth talking about? The only reason I mention it at all is that when you read other commentaries or watch weather media regarding upcoming storms the headlines are impressive until you find out they are referring to areas in the Central and Northern Mountains. So it is up to me to break the bad news that the Wednesday event they are referring to won’t impact us. Don’t get me wrong it is not everyone, but there are a few folks anytime I am up at Purgatory or just out and about around town that will ask about an upcoming storm only to be disappointed when I tell them it won’t affect us.

So let’s move on to the weekend. Does this look like something to talk about?

GFS

gfs-deterministic-colorado-snow_48hr-2491600

How about this?

Canadian

gem-all-colorado-snow_48hr-2491600

How about this?

Euro

ecmwf-deterministic-colorado-total_snow_10to1-2524000

Where is the snow down low? It is in liquid form, I don’t care I will take it at this point.

ecmwf-deterministic-colorado-total_precip_inch-2524000

You know the drill, things could change blah blah blah. But I like what I am seeing so far.

This winter is turning out to be quite a challenge and there has been a lot of trade talk about what is going on. I talked at length early on about the effect of the positive Indian Ocean Dipole. I have always tried to share how weather events around the world especially what is going on around Australia affects our weather. Incidentally the positive IOD I mentioned led to the drought in Australia and the fires followed.

One astounding thing I saw recently was the amount of cooling in the oceans relative to average the last months.

compday_E8YrYdcO8Y__1_

Check out the cooling in the North Pacific and East Pacific and the extreme cooling in the Arctic. Alaska and the Arctic have had one of the coldest winters in many years as a result of a positive Arctic Oscillation which keeps a lot of cold air over the extreme northern latitudes.

Here is what a positive AO results in for precipitation anomalies in the winter.

AO_Precipitation

Here are the last 60 days actual anomalies

cpc_gauge_global_nhemi_60day_anom_1379200

Here is the long term forecast for the AO

ecmwf-weeklies-all2-avg-ao-box-1897600

So hopefully we will get some relief. Last February 60% of the snow at Purgatory fell between Feb 18th and Feb 23. Last March Purgatory was just short of February’s snowfall by 10 inches. Don’t give up yet!

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A Difficult Way To Get Snow In SW Colorado

The models show our next batch of weather, for some, coming in on Wednesday. This will not be much of a storm, more of a reaction between moist air coming into Northern New Mexico mixing with cold air backing up to the continental divide to our east.

How far back west the cold retrogrades will determine who gets snow and how much. At this point, some of the models are trying to get a double play showing sub-advisory level snow at Wolf Creek with a slight push of SW flow while light snow falls around Telluride with westerly flow.

The last time this happened there was actually a storm moving into New Mexico from the west and Wolf Creek did well. This looks weaker to me at the moment so I would say based on blending the model amounts 2-5 inches would fall at Wolf Creek. I have pretty low expectations with this “event”. But we do have another 1 1/2 model cycles before coming to any conclusions.

By Friday it looks like the ridge will flatten out just in time for a closed low-pressure system to come and hit the South Central California coast, and start spinning moist air into the SW US and the Four Corners region.

The good news is the ridge, as I said, flattens out but the jet retreats to the north which means lower elevations could get some rain. I would not plan your weekend around the weather yet, there are a lot of things that could change to make this a completely different looking storm by the weekend, but it is the next best chance for decent snow.

Next Update Tuesday afternoon.

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Models Erase The Snow

This storm is going to stall out and very little moisture will make it south of the Central Mountains. Even Telluride and Silverton Mountain are going to be hard-pressed to generate snow greater than 3″. The main difference between yesterday and today is some of the models are trying to drive that cold front down further by late Tuesday which would result in another chance of light snow for areas north. It is almost not worth writing about.

By Wednesday, the models start to diverge and things get complicated. As I mentioned yesterday there are signs that we may see a pattern change in 7-9 days with a big storm coming from the right direction for our area.

If the snow does develop over the higher areas of 550 it will probably be late Sunday and it will probably be done by early Monday.

Just in case you are headed to the Northern and Central mountains here is what you can expect from the GFS and Euro.

Euro

euromon

GFS

gfsmon

The ratios up north will average about 15-1 so there will likely be more snow than appears on these models.

So we’ll keep grinding it out and hope this pattern changes, for those of you weather nerds who want to track what I am watching, look up  “EPO forecast” and  “AO forecast”, both of these teleconnections are forecast to go negative in about two weeks which will be the first time since December when we were getting more useful storms.

Next Update Monday.

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Light Snow Event Sunday

Yet another light snow event is on track to move in for about 18-24 hours on Sunday. Silverton Mtn and Telluride will be favored as the front sags to the south in northerly flow. At this point, I am not expecting any accumulations south of Electra Lake.

I still have no confidence in the split flow system on Thursday. However, I am still seeing signs of a potential pattern change in the 10-14 day period.

Accumulations look light in the 2-5 inch range for Sunday-Monday. This does not look like a good system for Wolf Creek. I will sort out the details on timing tomorrow.

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Back To The Drawing Board

A couple of chances of snow over the next 7-10 days. That is the good news, the bad news is the two storms look eerily similar to roller coaster we just went got off of. Another system caught up in the N/NW flow which slowly drapes its way south through Colorado Sunday night through about Tuesday, then a second storm develops Wednesday/Thursday as a cold front back-doors the area from the midwest while an area of low pressure moves into New Mexico and draws in moisture from the Gulf of Mexico and then blows up as severe weather on the southern plains.

While the sea surface temps don’t verify it, this season sure has looked like a La Nina with the blocking high pressure directing these systems overland north of California.

El Nino maps

We need a significant pattern change and the long term models are starting to align for that change to occur at the end of February and the beginning of March. That is not to say we can’t get big snow in this current pattern, it’s possible, but everything has to come together perfectly and we have not seen that happen since December.

NOAA’s long term CFS model shows that pattern change from February to March

February

cfsfeb

These are not temperatures but they reflect high (yellow and orange) and low-pressure (blue shades) represent low pressure with a mostly northerly storm track.

Here is the March upper air forecast

cfsmarch

This shows a stormy pattern for most of the US with the storms spending more time over water and coming into Southern California.

I am not confident enough to display the snow forecasts from the models yet, perhaps by the weekend.  Stay tuned! Next update on Friday.

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URGENT-Canceled

Not just a cancel (and misspelled twice by the way) but this was apparently Urgently canceled, and you can’t get much worse than an urgently canceled advisory. Meanwhile, Wolf Creek picked up another 5 inches out of nothing bring their total to 9 inches in this storm cycle and Telluride added 6 inches.

URGENT – WINTER WEATHER MESSAGE
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
730 AM MST TUE FEB 11 2020

COZ019-111530-
/O.CAN.KGJT.WW.Y.0008.000000T0000Z-200212T0700Z/
SOUTHWEST SAN JUAN MOUNTAINS-
730 AM MST TUE FEB 11 2020

..WINTER WEATHER ADVISORY IS CANCELLED

THOUGH PERIODS OF LIGHT SNOW WILL CONTINUE THIS MORNING,
ADDITIONAL ACCUMULATIONS WILL BE LIGHT. AS A RESULT, IMPACTS TO
ROADWAYS AND OTHER ACTIVITIES WILL BE MINIMAL AND THEREFORE, THE
WINTER WEATHER ADVISORY HAS BEEN CANCELLED.

There is a bright side, 5 days ago the GFS was saying this would happen and from that period on kept showing low to no amounts for Durango, I consider this a victory for the GFS and huge defeat for the NAM model (both versions). Tomorrow I will start tracking the next storm.

If for some reason the storm takes a wild jaunt north and we get some accumulation I will happily write another Update.

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Step 1 Look Outside

People think I am joking when I say look outside, but it is one of the most important things to do as a forecaster. Yesterday all of the models showed an initial surge of moisture around 3 am. It is not there.

Step 2, check out the surface maps. This maneuver is slightly overrated. We can bring back actors who are dead and sell hundreds of millions of dollars at movie theaters very easily with CGI. After billions and billions of dollars spent at the Department of Commerce (NOAA) we can’t come up with a useful surface map at the WPC (weather prediction center) and it gets more confusing when trying to compare it to the privateers who have tried to develop their own (Wunderground).

Step 3, check out the models. The models show snow starting after 7am in some areas. They have really tamed the storm and show it to be a pretty weak system coming across New Mexico with such light forcing that even the lay-up areas like Wolf Creek get a near miss with less than 5 inches during the day. Heavy flurries with no accumulation to 2-3 inches are likely for the rest of our forecast area. I know, it sucks.

Usually, a big miss like this leads to severe weather for Gulf Coast states so my followers from Texas to Florida will probably see this storm peak out. February 1st is the beginning of the early severe storm/tornado season in the south.

Since the models this year cannot accurately predict weather 12 hours away I am not going to talk about our other chances of snow in the coming days yet, but winter is not over yet.

Next Update later today.

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