**Winter Storm Watch Issued**


The National Weather Service in Denver has issued a Winter Storm Watch for much of Colorado including areas South of Denver, along the Palmer Divide and for Castle Rock proper. The watch means conditions are favorable for a storm that could make travel conditions difficult.

The watch runs from midnight Monday through about noon on Tuesday, the heaviest snowfall is expected during this period.

A Watch means conditions are favorable, we will look for a warning before deciding this storm is a sure thing. There is still considerable uncertainty with the storm track overall and that can make a huge difference in how much snow the front range sees.

Speaking of how the models are doing:


In the image above, the GFS is on the top and the NAM on the bottom. The GFS has backed down, just slightly this morning but model bouncing is still in play here. The NAM favors a more southern track to the storm which would mean less snow for Denver, but not necessarily less for those of us along the Palmer Divide.

The storm system has not moved onshore for the U.S. yet so models are still having trouble with the track. Any wobble could make a huge difference in the total snowfall.

For now we continue to stress the impact of the storm. We are not hyping it up, we are not telling anyone to be scared, this will not be the biggest storm we have ever seen, but it may be the largest this year.

Be prepared!

Confidence Increasing for Significant Colorado Winter Storm

WinterWxStory1_01302016Model guidance is beginning to agree that a large storm system will affect Colorado between Sunday night and Tuesday night. Each model across the board increased overall snowfall accumulations with last night’s run,  mainly due to a northward shift by several of these models. The biggest question still remaining is the final placement of the storm center. While many of these models have this in the same area, some of them do not which still creates uncertainty in the forecast.

What we know for sure as of this morning:

  • Nearly all models are in agreement that Colorado and especially the front range will see snow during the Sunday – Tuesday night period
  • The mountains and foothills will see heavy snow
  • Winds of 15-25 knots (17-28 mph) will be possible during the storm along the front range, this could create considerable blowing and drifting of snow
  • Front range could see periods of heavy snow and wind, especially later in the day Monday and overnight into Tuesday
  • Most models show between 10-25 inches total snowfall for this storm. Please keep in mind, this is still very early and we expect those numbers to change significantly in the next 24-48 hours

GFS predicted snowfall (top) NAM predicted snowfall (bottom)

This Could be a High Impact Storm

We continue to stress that should this storm set up correctly, the snowfall numbers won’t be the issue to look at. What will be important is the impact, at the end of the day, does it matter if you get 2 feet or 3 feet of snow if all the roads are closed and you are not able to travel? Nope! This storm is not really 50/50 anymore, it is more like 60/40 leaning towards a significant storm, this confidence should trend upwards with more consistent model runs today.

Use Saturday as your preparation day for these impacts!

  • A prolonged period of heavy snow and high winds is expected
  • Roads will become icy and snow packed, roads to our East may become impassable due to drifting snow
  • Airline cancellations and delays will be very likely
  • School and business closures will be possible
  • Travel will become very treacherous at times


Get your errands done today, get to the store and don’t leave anything to the last minute. Be prepared! Stay tuned here and we will provide more updates as this storm system evolves. Happy Saturday!


Next Week’s Winter Storm Update


The latest model runs from this morning have shifted our snowfall totals down for the period next week. Most were showing a healthy dose of snow at or over a foot yesterday, most are generally in the 6-12 inch range this morning. There are a couple of factors that seem to support this:

  • Models across the board are showing a slight shift to the South of the storm system’s center. This would mean a lot of the energy that was expected to hit the Denver area will slide South further. This will diminish our snow totals.
  • The high pressure systems to our Northwest and Northeast may not linger long enough to stall this storm out
  • If nothing blocks this storm and stalls it over Colorado, it will move more quickly through and exit the state sooner, this would also mean less snowfall.
  • There is a large low pressure system to the Northeast over Canada that may also influence this storm, again if this low moves to quickly, our storm will also move quicker.

This is the situation as we see it this morning, it is still worth mentioning that this storm is quite a ways out so this set of model runs is not the end-all be-all.

While I’m on the subject, a quick note about what I like to call “model bounce.”


Shown above are 3 GFS model runs in 24 hour increments starting with 1/27 and ending today. You can notice that the first run had Denver around 11 inches, the second bumped it up to 13.5 and as of this morning we are down to about 8.

This is something we see rather often with longer range models when they are still trying to get a grasp on a storm system. The further out we are from the storm, the tougher time the models have at predicting it. The GFS is a nice longer range model, but it struggles with snowfall on many days out from the storm system, so when I show these images please keep in mind that these are more of a guideline of what models believe the atmospheric set will be.

The main point here is still the impact scenario: the snow totals are not super important yet, they won’t be anywhere near accurate for a few days anyway. What the models are showing us is that there will be some duration of snowfall across the front range from the Sunday to Tuesday time frame.

At this point, this storm is still 50/50. I have not seen any evidence to support over a foot of snow and no evidence to say we couldn’t get 0 inches of snow. It’s simply too early to tell!

I’ll continue to have updates as this storm evolves, look for my official preliminary snowfall totals sometime on Saturday. Stay tuned!



Large Winter Storm Likely to Affect Western U.S.


Models across the board are in agreement on a large winter storm set to move into the Western U.S. I will admit, it is unusual to see them all pretty close to each other this far out from a storm, however it does happen from time to time. At this time, our confidence is high that some area of the Western and Midwestern U.S. will see a significant storm.

The big question and one the models don’t quite agree on at the moment is where it hits and how fast it moves. In Colorado and especially along the front range, this means everything. A wobble in where the storm sets up can mean the difference between a 2-4 inch snowstorm and a 15-20 inch snowstorm.


Let me clear, this is a setup we look for in large winter storms to affect the front range of Colorado, the ingredients are there. That being said, everything has to come together perfectly for this system to produce over Colorado. As you can see from the image above, I have outlined some of these features:

  • The low pressure system is expected to set up over Southeastern Colorado. This position allows the system to draw ample amounts of moisture from the gulf into Colorado. The counter-clockwise turn of the low allows winds to shift to the East or Northeast, providing upslope and enhancing snowfall
  • A high pressure system to the Northwest pulls colder air in from Canada. This is imperative to snowfall totals as the colder it is, the higher the snowfall will generally be. One other thing it can possible do, depending on it’s position; the clockwise turning winds around this feature can enhance the upslope flow coming off of the low to the Southeast.

Clearly the ingredients are there for this storm. We still have a few questions we need answered:

  • Where do the low and high set up? This is crucial, any wobble north or south of these features can be the difference between a monster snowstorm and a total bust!
  • How quickly does this system move? To see larger snowfall totals we would like that High Pressure system off the coast of Florida to block or stall our system for awhile. This would allow a longer period of upslope and snowfall.

Be Prepared!

This storm is about 50/50 right now on whether it will affect areas along the front range in Colorado. I am in no way saying this storm will hit us yet, but my concern is that if it does, it may be a doozy! Thursday and Friday are a great day to begin preparing;

  • If you need anything from the grocery store, Thursday and Friday will be your days to go. With the media already hyping this storm, I can see a lot of “store runners” out on Saturday and Sunday. Get there early and get your shopping done before the shelves are bear.
  • Get any medications filled you need, again Saturday and Sunday are going to be rough days to be at a grocery store.
  • Fill up the gas tanks in your cars, never know if/when this might come in handy.
  • Get the shovels and snowblowers ready!


This forecast will shift quite a bit over the next few days. There is no guarantee Denver will see anything from this storm just yet, but we need to be prepared because if it does hit the Denver area, it could be significant.

Stay tuned to our website and/or Facebook page, we will have updates on the model data and pass along any Watches or Warnings as they become available.


Castle Rock Weather: Next 7-10 Days

The good news is the next 4 days will be quite nice along the front range, but we are tracking a possible large winter storm for early next week.

The possible big change we are looking at starts as early as Sunday.



The first thing I’ll mention is that this far away from an event, looking at snow totals is pretty useless. These longer range models very rarely do well with that more than 3-5 days out from the event. What we are looking more at here is the atmospheric setup.

Looking closer at the Euro:


The main thing that jumps out at me here is that low pressure system and the high pressure system to our Northwest. The position of these two features will be key; the low pressure will be responsible for bringing moisture in from the gulf and creating upslope. The high pressure will be responsible for bringing colder air from the North into Colorado and depending on where it sets up, enhancing upslope further.

A look at the GFS provides a similar picture:


The brighter colors in this image signal stronger winds. The Northeasterly component of these stronger winds signals a strong upslope signal.

So a couple of takeaways here…

  • We are not yet saying a major storm system will hit us, it is far too early to tell
  • That being said, this is the type of setup we look for in the atmosphere for larger snowstorms along the front range of Colorado
  • Many ingredients have to come together than what I’ve explained here
  • I’ll have more posts over the next few days examining this setup and how it can make for a large or small winter storm depending on location and ingredients
  • Keep a close eye on information for this system going into the weekend! Don’t get caught unprepared!

Whatever your preferred source of weather, keep an eye for changes to the forecast through this weekend, of course if you follow us we will have updates throughout the week. Stay tuned!

Colorado Quiet – Major Winter Storm to Impact Eastern U.S.



The storm system that affected Colorado is now moving its way East and re-strengthening over Kansas. This will mean a few quiet days for us in Colorado and a few very hectic days out East. Some  areas could see nearly 3 feet of snow!

There are several watches and warnings out, if you are in any of the affected areas, be prepared for prolonged severe weather. Keep an eye on your local NWS for warning and advisory information. The NWS has brought in extra staff for these events so they will be the best source of information.





Castle Rock’s 2015 Weather Year in Review is Now Up!

All the data has been compiled, analysis has been run and we are ready to roll.

We present an overall look on how the year turned out for 2015 in Castle Rock. In a year dominated by El Nino and strange weather patterns, did 2015 turn out wild or was it pretty normal?

All the details are now up! Enjoy!

Click here for the 2015 Castle Rock Weather Summary



MWAVWX to Attend National Storm Chaser Convention 2016

This year MWAWX will make a return to the 18th Annual National Storm Chaser Convention. This event, originally started by a few friends sharing tornado videos from the past storm season has grown into a large conference featuring storm chasers from all over the country, notable speakers from the field of atmospheric science, engineering, and broadcasting.

Dr. Greg Forbes of The Weather Channel

Dr. Greg Forbes of The Weather Channel

This event showcases everything from scientific lectures, contests (including best weather photos/best storm chaser vehicle), demonstrations of weather radars and technology and classes and meetups for Storm Chasers.  Notable speakers from across the community attend each year including Dr. Greg Forbes of the Weather Channel, Tim Marshall, Dr. Howie Bluestein, Dr. Jason Persoff and of course, Veteran Storm Chaser Roger Hill.

Dr. Greg Forbes discussing surface observations

Dr. Greg Forbes discussing surface observations

Dr. Howie Bluestein discussing the 2013 El Reno OK tornado

Dr. Howie Bluestein discussing the 2013 El Reno OK tornado

This will be the first time this event will be held outside of Denver, taking place in Norman Oklahoma it is an excellent chance to see things we normally don’t get to see. We will be touring the National Weather Center on Friday before the convention starts.

In addition, Mountain Wave Weather will be live-blogging the event on our Twitter account. If you have any interest on what is going on at the convention, please visit this page!

See you in Oklahoma!

Mike Nelson, Chief Meteorologist at KMGH Channel 7 in Denver.

Mike Nelson, Chief Meteorologist at KMGH Channel 7 in Denver.

Dr. Jason Persoff is an MD specializing in Internal Medicine and research of mass casualty incidents. His presentation examines some of the health implicaitons for storm chasers including unhealthy diets on the road and sleep deprivation

Dr. Jason Persoff is an MD specializing in Internal Medicine and research of mass casualty incidents. His presentation examines some of the health implicaitons for storm chasers including unhealthy diets on the road and sleep deprivation