Moisture from Tropical Storm Javier will increase the threat for flash flooding across the southwestern United States by the middle of the week.
Localized flash flooding has occurred from monsoon thunderstorms over the past few weeks, but the threat will become more widespread across the Four Corners region on Wednesday.
"Javier will help to enhance the stream of moisture that has already been consistently feeding into the Southwest," AccuWeather Meteorologist Jake Sojda said.
The flooding has the potential to be life threatening in some communities.
"Wednesday will hold the most significant threat for heavy rain, thunderstorms and flash flooding from Arizona and New Mexico, into southeastern Utah and southwestern Colorado," he added.
While any storm in the Southwest has the potential to produce flash flooding, the greatest threat will focus on southern and central Arizona, including Phoenix and Tucson, and southwestern New Mexico.
Prior to midweek, Javier will skirt across Mexico's Baja California Sur with flooding rain and damaging winds.
Rainfall rates could exceed an inch per hour in any given storm across the Southwest.
"Rainfall amounts of this magnitude, and in as short of a period of time as they will come, can be very dangerous in the Desert Southwest," Sojda warned.
Residents and visitors should remain aware of the elevated risk for flooding across the region.
Downpours over higher terrain can quickly send a rush of water downhill through normally dry washes with little warning.
"Everyone in the region would be well advised to stay away from known stream beds and runoff chutes," Sojda stated.
Torrential downpours could drastically reduce visibilities along interstates 8, 10, 17, 25 and 40. Runoff from storms could send a flow of mud and rocks into area roadways.
Motorists are urged to never drive through a flooded roadway, as the flood waters can be deeper than they appear and the roadway underneath could be compromised.
Gusty winds from the storms could add an additional hazard to the region by kicking up dust and lowering visibilities.
The most drenching storms could continue into Thursday, mainly across southeastern Arizona and southwestern New Mexico.
A shift in the winds is expected to bring a much drier pattern to the affected regions from Friday into the weekend.