Severe Weather

Surge of Tropical Moisture From Ex-Javier a Flood Threat for Southwest U.S.

At a Glance

Former Tropical Storm Javier has triggered a surge of tropical moisture into the Southwest.
Blowing dust, flooding rainfall and dangerous lightning are all possible over the next couple of days.

Increased moisture in the Southwest is giving rise to a renewed threat of flash flooding the next few days, instigated in part by what used to be Tropical Storm Javier.

Moisture from Javier and to its east will be pulled into the Southwest U.S. by a southward dip in the jet stream.

Moisture associated with Ex-Javier and moisture to its east is being pulled north by a southward dip in the jet stream in the western United States.

All of this means that we will see widespread shower and thunderstorm activity in parts of Arizona, New Mexico, southern Utah, southern Colorado and West Texas through the end of the week.

The usual impacts from monsoonal moisture surges into the Southwest will continue to be in play the next few days. This includes heavy rainfall, flash flooding and dangerous lightning.

Flash flood watches have been hoisted by the National Weather Service in parts of the Southwest.

(FORECAST: Albuquerque | Flagstaff | Phoenix | Tucson)

(INTERACTIVE: Latest Southwest U.S. Radar)

Rainfall totals are forecast to be 1-3 inches in parts of the Southwest, though locally higher amounts are possible where clusters of thunderstorms stall. Heavier rain will be found in west Texas as a cool front begins to grab moisture from the Pacific on Thursday.

(MORE: Five Things to Look For During the Southwest Monsoon)

Thunderstorms across the Southwest can sometimes produce torrential rain in a short period of time. In these situations, rivers, creeks or dry streams (arroyos) can quickly fill and produce high water on roadways.

As always, you should never attempt to drive through floodwaters.

Just last week we saw the impacts of what storms during the Southwest monsoon can do. Slow-moving storms caused flooding in the northern Phoenix area on Friday where water rescues were reported.

(MORE: Flooding Last Week in Arizona)

It's easy to misjudge the depth of floodwater, particularly at night. Sometimes the bridge or road masked by flood water may have been undermined or completely washed out.

According to FEMA:

6 inches of water will reach the bottom of most passenger cars, causing loss of control and potential stalling.
1 foot of water will float many vehicles.
2 feet of rushing water will carry away most vehicles, including SUVs and pickups.