Mid-July, the week of July 12-18, saw the beginning of the annual western U.S. monsoon, and it was a timely occurrence for the region. The monsoon is a change in the prevailing wind patterns over the southwestern U.S. that happens every summer. It ushers in moisture from the Pacific Ocean and leads to shower and thunderstorm formation as the moist ocean air is forced upward by mountains in the region. This circulation pattern develops every year, although the strength of the pattern and its precipitation amounts vary from year to year.

This year, the monsoon circulation is expected to be robust with precipitation above- to much-above normal in the U.S. Intermountain West (the states of Wyoming, Colorado, Utah, New Mexico and Arizona). That is important precipitation; monsoon-related moisture accounts for over half the annual precipitation in most of these states. And if the forecast verifies, drought easing is expected to develop. That would be very welcome, as almost 95% of the Intermountain West is in drought with nearly one-third of the region in extreme to exceptional drought, according to the July 14 U.S. Drought Monitor. Drought development was intensified by an extreme snow drought in the 2025-26 winter season.

One element that may bring some enhanced moisture inflow to the western U.S. monsoon is the influence of El Nino in the Pacific Ocean. During an El Nino summer, the eastern Pacific tends to be more active than usual when it comes to tropical system formation. When these systems form, their remnants can sometimes be caught up in the monsoon flow from the ocean into the North American mainland. These remnants can offer some generous moisture and increased precipitation to the Intermountain West.

Because of the promising monsoon outlook, widespread drought easing is projected for the Intermountain West region. For July, the U.S. Climate Prediction Center (CPC) calls for at least a one-category improvement in drought conditions over Arizona, along with parts of Utah and Nevada. For the rest of the summer through the first and middle portions of autumn, ending Oct. 31, the CPC outlook notes, "During the remainder of July through the end of October, El Nino conditions are favored to have an increasing impact on climate anomalies. Enhanced monsoon moisture driven by warmer Pacific Ocean temperatures favors widespread drought reduction across the Four Corners region and much of the Rockies."

There is also the potential for some improvement in the volume of water the Colorado River brings to the Lake Powell and Lake Mead reservoirs. Strong El Nino events in 1983, 1997 and 2016 provided some very favorable precipitation for the water supply in these reservoirs. However, experts such as Colorado State University water and climate scientist Brad Udall caution that a reversal of long-term lower water volume in the Colorado Basin is unlikely. Both Lake Powell and Lake Mead are less than 30% full, according to U.S. Bureau of Reclamation assessments in early July.

Any El Nino-influenced precipitation is likely to occur in a generally warmer and drier long-term environment for the Intermountain West. The June 2026 NOAA National Centers for Environmental Information (NCEI) notes the U.S. West and Southwest climate regions "experienced their warmest January-June period on record and received less than 70% of their average year-to-date precipitation."

More DTN discussion on the 2026 El Nino is available here: https://www.dtnpf.com/…

Bryce Anderson can be reached at bryce.anderson@dtn.com

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