Truckers will have to dodge monsoonal thunderstorms for another day in the Desert Southwest.

An unstable, humid air mass over the region will produce more storms Wednesday. Some of them could produce periods of torrential rainfall in some places, leading to potential flash flooding and possible road closures.

The National Weather Service has flash flood watches in place across large portions of Arizona and New Mexico, as well as smaller sections of southeastern Utah and southern Colorado. Rain totals could exceed 2 inches in some locations. This includes Phoenix, Tucson, Kingman, Bullhead City and Lake Havasu City, Arizona; Albuquerque, Santa Fe and Gallup, New Mexico; in addition to Telluride and the San Juan Mountains in southern Colorado. For some areas, the watches don’t expire until Wednesday night.

This type of weather isn’t unusual in the Southwest this time of year. According to the NWS, the region’s summer monsoon season runs from June 15 through Sept. 30. The University of Arizona Climate Assessment for the Southwest says Arizona and New Mexico receive up to half of their annual rainfall during the summer monsoon.

Some of the heavy rain may hit wildfire burn scar areas, possibly causing debris flows. Wednesday’s storms could also produce severe winds in some places, even where rain doesn’t fall. This could lead to blowing sand, dust and dirt that may reduce visibility.

Impact on freight

Some drivers heading into the Southwest will experience temporary delays due to the monsoonal storms. The latest FreightWaves Headhaul Index Weekly Change (HAULW) shows more inbound trucks than outbound in most Southwest freight markets.

(Map: FreightWaves SONAR Headhaul Index Weekly Change (HAULW). To learn more about FreightWaves SONAR, click here.)

This is indicated by the red shading and includes the Phoenix, Tucson and Albuquerque markets. This means there’s loose capacity in these areas, with more trucks (and drivers) than outbound loads being offered by shippers to carriers compared to a week ago.

Click here for more FreightWaves articles by Nick Austin.

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