Fox News Weather Center

Monsoonal Moisture to Bring Flood Risk to Interior Southwest US This Weekend

A surge of tropical moisture associated with the summer monsoon will bring the risk of flooding to the interior Southwest this weekend.

This could potentially spoil weekend plans around cities such as Las Vegas and Phoenix with thunderstorms forecast to be widespread across the region on both Saturday and Sunday.

Southwest Short-Range Regional Weather Forecast

The morning hours will be the driest part of the day before rain and thunderstorms become more widespread during the afternoon and evening hours.

People visiting the region who are looking to partake in site-seeing should take advantage of the drier conditions in the morning before the rain and thunderstorm activity ramps up in the afternoon.

Clouds associated with the rain and storms will help to limit sunshine and keep temperatures 5 to 15 degrees below their typical summer levels.

In addition to the rain and clouds, the surge of monsoonal moisture will also bring an uptick in humidity, making it feel a bit on the muggy side throughout the weekend.

Flash flooding will be the greatest danger brought by the stormy weather this weekend with blinding downpours potentially dropping over an inch of rain in under an hour.

Rainfall rates this high can quickly cause water to pond on roads and for some roads to become completely flooded. In the most extreme cases, flood waters may force road closures until the water recedes.

If you come across a roadway that has been flooded, you should remember to never drive through it as the water can cause your vehicle to stall, trapping you in the high water.

While a bulk of the rain will focus over the deserts, a few showers or thunderstorms may drift westward over the San Jacinto, San Bernardino and San Gabriel mountains of Southern California.

As a result, the Southern Californian cities of San Diego, Los Angeles, Riverside, Long Beach and Oceanside could all receive some rare July rain.

Unfortunately, the rain that falls across the region this weekend will not have a meaningful, long-term impact on the severe drought that has plagued the Southwest for the past several years.

The surge of monsoonal moisture is forecast to break down heading into the start of next week, allowing for drier weather and lower humidity to return.

However, there is the potential for another rain-maker to move into the Southeast early in the week.

Hurricane Dolores developed over the eastern Pacific ocean earlier in the week and is forecast to take a northerly tack through the early part of next week, making a close approach to California.

It is unsure at this point the exact path that Dolores will take, but it is unlikely that it will make landfall on California.

Even though the center of the weakening tropical system is expected to stay out to sea, moisture associated with Dolores could still move over California, delivering some rain to the state.

There are still some uncertainties about the exact path that Dolores will take and how much moisture will peel off across California, so continue to check bay with throughout the weekend as more becomes known about the outcome of this system.