Our string of hot weather has subsided temporarily as a cold front swang through late Monday night. That cleared us of the smoke and haze that blanketed the state. We’ll only have a short break of “cooler” weather before the heat builds back in. Our next saving grace? Some monsoon moisture looks to bring clouds and the chance of rain to the region by this weekend. It will be our first dose of monsoon moisture this year. And hopefully not our last!

First off, the monsoon is a seasonal wind shift that brings in sub-tropical or tropical moisture into the Four Corners region from the Gulf of Mexico and Gulf of California.

What that looks like varies on the exact event but normally, high pressure will set up over the central US while a heat low (or Monsoon low) sets up over southern California and SW Arizona. The wind flows around each of these circulations in a way that draws in tropical moisture.

Example of how the wind shift causes monsoon moisture to get pulled in.

You can notice that moisture gets pulled in from two distinct moisture sources and this increase in moisture, along with daytime heating, allows for numerous storms to pop. This is a very similar setup to what will be happening in the coming days.


Over the next few days, an area of high pressure will bake portions of the central US with triple-digit heat indices. For us, that’s kind of good news as the flow around that high will pull in Gulf moisture.

As tropical moisture becomes abundant, we’ll see consistent daytime storms erupt and take note because monsoon storms can pack a punch. Usually very heavy, intense rain will fall along with lots of thunder and lightning. For the most part, these storms stay sub-severe (usually there is no hail or tornadoes with the monsoon) but there can be intense flash flooding, very strong winds and potentially a lot of lightning which are threats that should be taken seriously.

With the incoming monsoon moisture, it’s looking like New Mexico and Colorado will benefit the most. Notably, it’ll be southwestern Colorado and northwestern New Mexico that see the biggest surge of rains but all areas of the Four Corners region will see the chance of rain and storms increase with this influx of tropical moisture.

Zooming into Colorado, you’ll notice just how much rain could fall over the next several days and how the focal point is over the San Juan mountains. This event will begin Friday and last through early next week.

A widespread 1-2 inches of rain may fall between Friday and Monday over the San Juans. Great news for their ongoing awful drought. This will hopefully aid in dampening the soils and wetting the trees – and hopefully suppressing any fire concerns at least for a little bit.

Looking at the chance of precipitation from Thursday to Monday shows the influx of moisture over this weekend and where the best shot at seeing some monsoonal rains is.

Thursday we really don’t have much of a shot at seeing rain but that chance goes up Friday across the mountains and western Colorado. Then, Saturday and Sunday come with rather high chances of rain and storms followed by a decrease in activity as we head into early next week.

If you have weekend plans, take note that many mountain areas, especially the southern and central mountains, will have the chance of thunderstorms.

Although some rain is coming over the weekend, this is great news for the state and the high terrain. The best chance for the Urban Corridor to catch rain will be Sunday although Saturday and Monday could provide a few rouge storms.

Other than the afternoon storms forecast, we’re also watching a decent amount of heat building back in. Here’s a look at afternoon highs this weekend – if you fall under a storm, you’ll obviously cool off a bit but if you don’t – it’ll be hot.

Have a good weekend!

~ Andy

One response to “Monsoon Moisture to Bring Beneficial Rain to Southern and Western Colorado”

  1. “swang”?

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