Monthly Archives: July 2017

Less hot, better chance for rain

6:55 AM, Tuesday, July 25, 2017

Beginning today and for the next few days we will see more afternoon cloudy periods, cooler daytime temperatures, and a better chance for showers and thunderstorms.


The 2017 North American monsoon has been active but it has been mainly south and west of the Denver-Boulder-Fort Collins-Cheyenne area. There were a few days late last week when a plume of moisture moved over the Front Range region, but it was mainly upper level moisture and so there were limited amounts of rain reaching the ground. This morning there are already showers across parts of western Colorado as another monsoon moisture surge moves north. That should increase chance for showers and thunderstorms this afternoon and tonight (and again Wednesday and maybe Thursday) for northeastern Colorado and the Front Range. There could even be some locally heavy rain.

The North American monsoon

12:35 PM, Wednesday, July 19, 2017

The North American monsoon, sometimes called the Southwest monsoon or the Mexican monsoon, is a seasonal weather pattern that in some years can bring enhanced rainfall across the southwestern U.S., including the Front Range region. The impacts for the Front Range are seen in the climate record from mid July through the late summer.  In a nutshell, showers and thunderstorms erupt daily along the Mexican Sierras as the tropical Pacific heats up and that pumps lots of moisture into the atmosphere. Some of that moisture makes its way north into the southwestern United States. In the Front Range region not every year sees the effects, and the surges of moisture can be intermittent.


The 2017 monsoon has arrived, but for the most part the moisture has been in the upper levels of the atmosphere and so rainfall has been sparse despite afternoon clouds (there has been more moisture and areas of rain from Colorado Springs southward). Over the next two or three days a moderate plume of moisture (mainly middle and upper levels) should result in some afternoon and evening showers and thunderstorms. It’s not a highly anomalous amount of moisture, but it’s the best we have seen in a while. The best chance for rain is over the mountains of western Colorado, but I am holding out some hope for the Front Range too.


A little better chance for rain

3:35 PM, Monday, July 10, 2017

There hasn’t been much to write about lately, unless you want to worry about the increasing dryness of the local forests.


This week is bringing the best chance for afternoon/evening showers and thunderstorms. It’s not a guarantee, and some areas will get by with some clouds, maybe thunder, but little or no rain. But a bigger portion of the Front Range region may see rain ¬†this evening or one of the next few days. A few local spots may even get a soaking downpour.


With the greater amount of afternoon clouds temperatures should be less hot, but still quite warm.