DENVER (CBS) — The clouds and thunderstorms that showed up over Father’s Day weekend are all part of an early-season monsoon blast.
The full name is the North American Monsoon. Which simply amounts to a reversal of the wind pattern. A pattern that gives the Rockies most of its moisture during the summer months.
Here is the set up for the summer monsoon. An area of heat and high pressure forms over northern Mexico in early summer.
Now, officially, the monsoon season runs from June 15 to the end of August. But, most of the moisture from the Gulf of Mexico in this early part of June to mid-July enters Arizona and New Mexico.
On average, as the first part of July approaches, the anticyclone moves north, allowing moisture from the Pacific to enter the mix as well.
Then it’s Colorado’s turn! At some point in midsummer, the center of the high pressure ridge oscillates between Colorado and Texas. This opens the door for the development of showers and thunderstorms in the south to north flow in the state on the west side of the high pressure area. This is called a “burst” of humidity.
The anticyclone can return from time to time towards the west and cut the current which dries things out. This is called a “pause” in the monsoon.