The annual Southwest monsoon season is getting a boost from a Pacific hurricane, leading to an increase in showers and storms in Arizona and New Mexico this week.

Wetter Pattern Has Arrived

A pattern change has developed in the western U.S. over the past few days, with a low pressure system forming near the Pacific Southwest. That low in tandem with a ridge of high pressure over the south-central states and northern Mexico is increasing the flow of moisture into the Southwest. Eastern Pacific Hurricane Flossie is also helping to push the surge of moisture into the Southwest.

The upshot is that all of this moisture is leading to an increase in showers and storms in the Southwest through Thursday. Thereafter, a drier pattern should return for the Fourth of July weekend.

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Already this week we've seen the increasing number of monsoon-driven storms trigger a haboob, or dust storm, in southern Arizona on Monday. Tuesday's storms brought strong winds that gusted over 60 mph to Las Vegas, downing power poles and trees and contributing to blowing dust.

Additional bouts of storms on Wednesday could lead to locally heavy rainfall, strong wind gusts and more blowing dust in parts of Arizona, southern New Mexico and southern Nevada. Below is a look at the latest radar showing where rain and storms are ongoing right now.

(MORE: Further beef up your forecast with our detailed, hour-by-hour breakdown for the next 8 days – only available on our Premium Pro experience.)

What You Should Know About The Monsoon

• The monsoon is a seasonal wind direction change, not an individual thunderstorm. Monsoon is a term used in multiple parts of the world that refers to a seasonal wind shift that has wet and dry phases. In the Southwest U.S., winds change from a more westerly direction during the dry phase to a southerly direction during the summertime wet phase, which pumps moisture from the Eastern Pacific and Gulf into the region.
• The start of the monsoon varies from year to year. June 15 is when the monsoon officially begins, but in many areas, it takes until late June or even July for the coverage of storms to grow. The thunderstorm activity then varies in intensity from day to day or week to week through August and September.
• The monsoon is the main driver of rain for the Southwest. Most of northwestern Mexico and the southwestern U.S. receive over half of their annual precipitation from the monsoon.
• The monsoon also brings dust storms, flooding and lightning. Thunderstorms can generate huge dust storms known as haboobs that can lower visibility and cause air quality concerns. Canyons and arroyos can become victim to flash flooding even if it isn’t raining. Floodwaters can travel many miles downstream through canyons. Early in the season, prolific lightning can create fires until the ground is moistened.
• Hurricanes can cause rapid upticks in monsoonal moisture. Occasionally, remnant spin and moisture from former Eastern Pacific tropical storms or hurricanes can be pulled into the Desert Southwest, enhancing heavy rainfall. Two tropical systems – Hurricanes Kay in 2022 and Hilary in 2023 – have caused flooding in California.

Jonathan Belles has been a digital meteorologist for weather.com for 9 years and also assists in the production of videos for The Weather Channel en español. His favorite weather is tropical weather, but also enjoys covering high-impact weather and news stories and winter storms. He's a two-time graduate of Florida State University and a proud graduate of St. Petersburg College.