AZ Monsoon

Desert Monsoon weather, facts and details

What is Monsoon?  The word monsoon is derived from the Arabic word mausim, which means season. Traders fishing the waters off the Arabian and Indian coasts noted that dry northeast winds in the winter suddenly turn southwest during the summer, and bring heavy rains to Asia.

mexico arizona storm weather

summer Monsoon flow graph

We now know that these MONSOON, large wind shifts from dry desert areas to moist tropical areas, occur in other parts of the world including Arizona.  Strong yearly variations of temperature over land masses is a primary cause of MONSOON.

Tucson Phoenix Monsoon Season map

Monsoon Information weather chart

The monsoon weather in Arizona is not as intense as Monsoon season in Asia and India mainly because the Mexican Pleateau is not as high or as large as the Tibetan Plateau in Asia.  In Arizona, the monsoon process starts with the hot and dry weather of May and June.

Tucson, Phoenix, AZ Monsoon weather storm clouds

Monsoon dark clouds over Coronado Mountains

Most of Arizona’s humid air comes from the Sea of Cortez and the Gulf of Mexico. Our hot desert sun heats the moist air causing the familiar thunderstorm cumulonimbus clouds.

Monsoon weather Arizona storm clouds

Cumulus clouds, Monsoon thunderstorm

Cumulus clouds are a type of cloud with noticeable vertical development and clearly defined edges. Cumulus means “heap” or “pile” in Latin.  These clouds typically form when warm air rises and reaches a level of cool air, where the moisture in the air condenses.

If the top of the cumulus cloud reaches above the altitude where the temperature is at or below the freezing level, then precipitation from the cloud is possible. 

Arizona Monsoon Thunderstorm dark clouds

dark cumulus storm clouds Arizona

Usually by May or June,  our strong Arizona heat causes temperatures to soar over these desert land areas. The intense heat causes surface air pressure to fall, forming an area of low pressure known as a thermal low.

Eventually, the cooler and much more humid air over the ocean is drawn toward the hot, dry air over land. This moist air moving onto the hot land eventually becomes unstable and develops into thunderstorms.

Once this occurs and rain begins to fall, humidity levels increase over land, which only triggers more thunderstorms, now you have the Arizona Monsoon Season.

This cycle will continue until land areas begin to cool in the early fall and the monsoon gradually ends.

Dark Monsoon Storm Clouds Arizona

Thunderstorm cumulonimbus clouds

Until the late 1970s, there was serious debate about whether a monsoon truly existed in North America. However, considerable research, which culminated in the Southwest Arizona Monsoon Project (SWAMP) in 1990 and 1993, established the fact that a bonafide monsoon, characterized by large-scale wind and rainfall shifts in the summer, develops over much of Mexico and the intermountain region of the U.S.

Dark Thunderstorm Clouds Monsoon

Monsoon Clouds , Microburst cloud in desert

Rainfall during the monsoon varies with distinct “burst” periods of heavy rain and “break” periods with little or no rain. Monsoon precipitation accounts for a substantial portion of annual precipitation in northwest Mexico and the Southwest U.S.

Southwest Monsoon weather clouds

Monsoon Clouds Arizona

 

storm clouds Arizona desert

Sunset after a Storm

As the Monsoon storm ends the clouds change with red and orange shades on the horizon.

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7 replies »

  1. Hey was wondering if you would be willing to part with some of your mesquite tree seeds near the end of summer? Having a hard time finding a good hybrid mature tree that I have access to take pods from.

    Liked by 1 person

    • It would be my pleasure! Two of our Chilean (no thorns) hybrid species are very healthy and enormous. We also have Native – Velvet and Honey Mesquite. You can email me an address and what seeds/pods you would like and I will send them.
      Blessings,
      Tj

      Like

      • Oh I just saw your question. Speed of monsoon and quantity of rain varies in different regions of India as it is a large country. In India annual rainfall averages between 750–1,500 mm (30–59 in).
        Thanks and regards.

        Like

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