Trudy is off the Mexican coast, but its moisture will pour into the southwestern U.S. and will help fuel a multiday flood risk across seven states this week from California to Colorado.

A dip in the jet stream will also funnel in moisture from the Pacific as a strong low-pressure system moves into the region.

Timing out this week’s rainfall

Wednesday: The highest risk of flooding on Wednesday covers much of Arizona and parts of New Mexico, as well as southern portions of Colorado and Utah.

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There will be an abundance of moisture available to support heavy downpours and training storms. This means storms will produce heavy rain over the same areas for long periods of time. The Weather Prediction Center is forecasting rainfall rates as high as 2 inches per hour. 

Some of the biggest concern will be the possibility of mudslides over recent burn scar areas as well as slow canyons and arroyos. 

If you have plans to visit any of the national parks in the West this week, make sure you check the forecast daily and pay attention to any warnings or advisories issued.

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There is also a slight threat of severe weather on Wednesday for portions of Arizona and western New Mexico. Isolated strong wind and hail are the main threats, but a brief tornado is also possible.

Thursday: Moisture will continue to pump into the Southwest on Thursday, only enhancing the flood threat on already saturated soils. 

Some forecast models are alluding to near record levels of moisture available for October in this region, which means there’s a great concern for flooding and the possibility that rainfall amounts could end up higher than currently forecast.

While the greatest risk for flooding moves out of California, it remains for much of Arizona, Nevada, New Mexico, Colorado and Utah. This includes places like Las Vegas, Phoenix, Tucson and Albuquerque. 

How much rain and snow is expected?

Right now, we are expecting as much as 3 inches of rain across portions of the Desert Southwest, which is more than enough for flash flooding in this region. Some isolated locations could see up to 5 inches. 

And yes, we could even squeeze some snow out of this system for some of the higher elevations. 

Parts of the Sierra and Rockies could see the first significant snow of the season. This could be a nice base for some of the ski resorts that were robbed of snow last winter. 

While widespread snowfall totals will stay under 6 inches, we could see isolated peaks pick up a foot of snow. 

Make sure you check back often, as the forecast could change. And don’t be caught off-guard if you are traveling through some of the higher elevations, as the rain could change to snow quickly.