Denver cyclone and related SPC predictions

[Ethan Lang]

One thing that has been bugging me is that in the OU scams tornado forecasting workshop put on by Rich Thompson he talks about the "Denver cyclone" and the idea behind it. One thing I have noticed over the past few years is that nearly every setup whether it be a mrgl or slight seems to produce tornadoes in Colorado. With this being the case why don't we see higher risk outlooks and more tornado watches from the SPC?

Sent from my Moto G (5) Plus using Stormtrack mobile app

 

[Marc R. O'Leary]

Because Colorado tornados tend to be weak at best, and as recently witnessed, land spouts abound. From a tornado specific standpoint, CO has good frequency, but from an intensity and more specifically a damage record, were pretty far down the list for anything really worth discussing.

Hail is another story.

 

[Jeff House]

The DCVZ can be a gold mine for chasers, esp if one is good with a landspout. Good news as Marc writes, landspouts impacts to people and property tend to be less severe than that of stronger tornadoes. Keep in mind the SPC forecasts probabilities for the public; low is not necessary a deal breaker for chasers.

The DCVZ can produce traditional tornadoes as well. Personally I'm good with a landspout, either way. For chasing if one can have some physical geography under a boundary, odds of success increase. I am a DCVZ fan though I usually do not go that far west. Some of the same processes happen with Cheyenne Ridge and Raton Mesa (south/Pueblo). Manage expectations (landspout v tornado) and the geography can be a nice help.

 

[Billy Ahlers]

The DCVZ can be a gold mine for chasers, esp if one is good with a landspout. Good news as Marc writes, landspouts impacts to people and property tend to be less severe than that of stronger tornadoes. Keep in mind the SPC forecasts probabilities for the public; low is not necessary a deal breaker for chasers.

The DCVZ can produce traditional tornadoes as well. Personally I'm good with a landspout, either way. For chasing if one can have some physical geography under a boundary, odds of success increase. I am a DCVZ fan though I usually do not go that far west. Some of the same processes happen with Cheyenne Ridge and Raton Mesa (south/Pueblo). Manage expectations (landspout v tornado) and the geography can be a nice help.

Wow!! I have been a hobbyist spotter chaser in the Denver area for a number of years and am only now learning of the DCVZ. I am grateful I found this site!! Prompted me to go to weatherprediction.com and they have a whole write up on it. It answers so many questions I have had over the years. I am amazed I have never heard about it. I have only recently started to expand my knowledge base to learn more about forecasting. Prior I had left all the forecasting up to the smart guys and just tried to get lucky when they said it was favorable. This has lead me to using wind flows more and convergence zones. I noticed that there is so often a convergence along our foothills. I thought it was just colder air basically falling out of the higher terrain meeting up with that southerly flow. Since Ive been more into forecast It answers a lot of questions I have had. Why so often the cell dissipate when they had such strong growth so quickly. Among other things. I have been using the wrong formulas for this area. Thanks!!

 

[Mark Blue]

Al Pietrycha has done some extensive work in this area. He has several webpages where you can find additional information regarding the DCVZ that would be worth your time to look into. You can find the information here: http://www.stormeyes.org/pietrycha/index.html.