What is Monsoon and why does it mess with my summer in the Southwest desert?

Big clouds, loud thunder, and lots of water!!!

Let’s get it right. A monsoon is not a storm. It’s a season. So, when your local weatherman issues a “Monsoon Alert” he/she is incorrect. Think of a monsoon like the southwest equivalent of hurricane season or tornado season. The actual storm is a Thunderstorm. Those of us that have spent any time in the southwest desert know these storms can be fatal. Many times they cause flooding, road accidents, occasional wild fires, and in rare cases a fatality.

Starting in late May or early June, the sun warms up the deserts in northwestern Mexico and the southwestern United States. The air gets so hot and excited that it can’t wait to go share its energy with the cold upper atmosphere. This rising air lowers the air pressure above the desert, creating a bit of a vacuum, especially compared with the colder air over the ocean (the ocean does not get nearly so excited about the summer).

Because nature always balances its forces, the cold high-pressure air from the ocean wants to blow into the desert. When it comes, it brings water with it. But there’s a problem: At the same time all of this is going on, a ridge of high-pressure air sets up shop in Mexico. In June, this ridge mostly blocks moisture from flowing north from the Gulf of California and Gulf of Mexico.

By mid-July, however, this ridge migrates north into the United States, where it bums around New Mexico and the four corners area. The farther north it gets, the more it allows moist air out of the gulfs into Southern Nevada — hence the humidity that sets your air conditioner intermittently wheezing through the end of September.

Now, when that air of the gulfs is especially moist, it’ll bump up against our mountains and condense into thunderheads as improbably high and menacing as the mold in a bachelor’s jar of olives. In the late afternoon or early evening, the now-saturated clouds burst: lightning, sudden downpours, howling winds and sometimes hail.

Monsoon season also causes your evaporative cooler to work less efficient because of the increased humidity. When you are shopping for a home, I recommend you have an air conditioning unit. An evaporative cooler can save money but is not sufficient for year round cooling. Having both systems is best! Call or email me today for other tips for your home purchase in our Southwest desert. Bob Armstrong, barmstrong@afg-realty or 760.221.2999

*parts of this post are taken from the Las Vegas Sun, Brendan Buhler author.