Fox News Weather Center

Dangerous flooding may unfold in southwestern US as Newton threatens 2 months' worth of rain in hours

Topic driven playlist

Significant flooding may develop across the southwestern United States during midweek as Newton fuels soaking rain across the region.

Newton slammed into Baja California as a Category 1 hurricane early Tuesday morning. Despite weakening, the system will send a surge of torrential rain into the Southwest through Wednesday night.

Downpours will initially increase Tuesday night across southern Arizona and New Mexico, sparking localized incidents of flash flooding.

On Wednesday, a more organized swath of heavy, flooding rainfall will arrive across southeastern Arizona. Phoenix will be located along the northwest periphery of the heavy rain, as the core of the steady rain will target areas farther east across southeastern Arizona, including Tucson.

One to 3 inches of rain can accumulate in less than 24 hours, and in a few cases, only a matter of hours. This amount of rain is something that typically accumulates over the course of one or two months in many Southwest locations during the late summer.

"Tucson averages just 1.29 inches of rain during the month of September, and some areas in and around Tucson could get that much rain in just one day," said AccuWeather Meteorologist Brian Thompson.

The excessive rainfall can quickly flood streets and prompt rockslides in the more mountainous terrain, both of which can lead to road closures.

In addition to street hazards, typically dry stream beds and drainage areas can become quickly inundated with water.

"Streams, rivers and drainage areas can flood quickly with these tropical downpours, so be prepared for rapidly changing conditions into Wednesday," said Thompson.

Hikers in the region should be aware of these dry stream beds and drainage areas as they can quickly turn into raging rivers.

The heaviest rain will taper off across Arizona Wednesday night as it shifts eastward into New Mexico.

Although similar threats will continue in New Mexico, flooding incidents will become more localized since the intensity of the rain is expected to diminish.

Gallup and Truth or Consequences, New Mexico, will be among the cities at risk for flooding rainfall Wednesday night. Rain, some heavy, will move into Albuquerque, New Mexico, but the overall risk for flooding is rather low.

The rain will move out as quickly as it came in. A period of drier and warmer weather will then quickly follow Thursday and Friday across the region as sunshine prevails, allowing for cleanup in flooded areas.