A Slow Transition Ahead

Today there is a slight chance of a few storms developing, especially in the higher elevations. After a bone dry day yesterday, some moisture has started to filter in from the southwest. The models are showing a slight uptick in surface CAPE this afternoon. CAPE is the energy in the atmosphere necessary to develop thunderstorms. Here are the max CAPE values in Durango today.

CAPE at noon


500 is usually the minimum where you can see development. You can’t help but notice the values on the Front Range between 3000-5000. This means severe weather is nearly a guarantee.

A couple of parameters I don’t use for our area are fun to look at today with these very high CAPE values across the NE plains of Colorado.

Here is the Significant Tornado Parameter (STP or SigTor) for this afternoon. This is a multi-component index which combines many values (including CAPE) and determines the possibility of a F2 or higher tornado developing. It is similar to what the Weather Channel calls the “TORCON” index.


Again, this is something I would never use in SW Colorado but it is fun (in a geeky way) to look at.

We are going to be slowly transitioning back to afternoon thunderstorms for the high country. These are not monsoonal, they are considered high altitude heat-based thunderstorms. They can but don’t always produce rain, a few of them occasionally drift off the mountains and remain intact over the lower elevations. Not monsoonal, not yet.

A couple of days ago I was talking about us easing into what appears to look like precipitation with more a monsoonal signature to it after the 21st. It is very difficult to track this pattern change, it always is. It usually defies the models. So the period after the 21st is just what I am seeing now, it could start earlier or later.

It is best to use a multi-model approach when looking that deep into the crystal ball. Here are the latest 15-day precipitation forecasts from the big three multi-models. The Euro is slowly coming around.

Euro DGO .44″, Telluride 1.55″ Cortez .24″









If you are somewhere today where a storm develops let me know. Thanks for your support and thanks for following the site!

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