Southwest monsoon season shows signs of life after delayed start

The Southwest monsoon season generally kicks off June 15 and lasts through September, but 2023 got off to a slow start due to weather patterns likely caused by a strengthening El Nino in the Pacific Ocean.

PHOENIX – The FOX Forecast Center is tracking the initial rounds of monsoon moisture that promise to produce the season’s first showers and thunderstorms across the Desert Southwest.

In typical fashion, any storms that develop will have the potential to produce flash flooding and wind gusts to 60 mph.

The chance of rainfall is typically common between June 15 and the end of September but got off to a slow start this summer due to weather patterns likely caused by a strengthening El Niño in the Pacific Ocean.


"El Niño events can delay the onset of the monsoon in Arizona and New Mexico by weakening and repositioning the subtropical high that guides moisture into the Southwest," authors of a NOAA climate assessment team wrote.

Many cities in the Southwest, including Phoenix and Albuquerque, New Mexico, usually report their heaviest rainfall events of the year during the monsoon season.

Typically, the pattern can lead to a community seeing 40-50% of its annual rainfall, which helps damper drought conditions.


While beneficial, consequences of the heavy rainfall include flash flooding, mudslides, increased lightning and gusty winds that can trigger dust storms outside of the thunderstorm activity.

A recent study found that some dust events are more deadly and impactful than hurricanes or wildfires, but their effects go unreported.

Dust storms are triggered when gusty winds pick up sand and small debris and form what appears to be a wall of clouds that can be miles long and thousands of feet high.

These sudden events are known to quickly reduce visibilities similar to that of a blizzard seen in more northern latitudes.


Expected rainfall amounts over the next few days.
(FOX Weather)


Over the next week, some forecast models show some communities picking up between 1-3" of rainfall.

Southern and eastern Arizona, much of New Mexico and southern Colorado are all included in the zone that could see scattered showers and storms associated with the monsoon.

So far, there are no early indications that the weather event will kick into overdrive similar to what some areas experienced during the 2022 season.

The National Weather Service said last year’s season ranked as the ninth-wettest on record and produced the most rainfall since 2006.

"There was a little bit of a late start this year, primarily because of El Niño," said FOX Weather meteorologist Kelly Costa. "I do think the farther and farther we get in time over the next couple of weeks, we’ll truly start to see the real start to the monsoon season, which will help with the temperatures a bit, just a bit, but it will really help with the wildfire situation."