Moisture from Tropical Rainstorm Simon will fuel heavy rain and thunderstorms over the Southwest through Wednesday before shifting over the Plains.
Rain and storms will expand across Arizona throughout the day on Wednesday before reaching into western New Mexico on Wednesday night.
The heaviest rain is expected to focus on the southern half of Arizona with several inches of rain possible through Wednesday night.
Some of the cities in Arizona that are encompassed in this zone include Phoenix, Tucson, Flagstaff and Safford.
"Normally dry washes and arroyos may turn into raging waterways, while mudslides could occur over the higher terrain," said AccuWeather.com Senior Meteorologist Kristina Pydynowski.
Roads may become impassable for a time during or immediately following the heavy rain, bringing traffic to a standstill.
For some, this may be reminiscent of when Odile delivered flooding rain across the interior Southwest.
Know when the rain will begin by using AccuWeather.com MinuteCast™. It has the minute-by-minute forecast for your exact location. Type your city name, select MinuteCast™, and input your street address. On mobile devices, you can also use your GPS location.
Despite the dangers that Simon brings, the rain will be beneficial to help ease the ongoing drought conditions.
Much of Arizona and New Mexico have been classified as being in at least a moderate drought by the U.S. Drought Monitor, although some of the ground in these states has seen improvement over the past several weeks from rounds of tropical rains.
Unfortunately, the rain from Simon will miss California, the state feeling the most extreme impacts from the ongoing drought.
The moisture left over from Simon is expected to shift into the Plains through the second half of the week, enhancing rainfall from Oklahoma to Kentucky.
This could result in localized flooding and keep temperatures well below normal across the region on Thursday and Friday.