Hurricane Polo, which rapidly strengthened from a tropical storm Monday afternoon, is now a Category 1 hurricane off the southwest coast of Mexico and is expected to intensify quickly, bringing a heightened flood threat to the U.S. Southwest beginning Tuesday.

According to the National Hurricane Center (NHC), Polo was located about 270 miles southwest of Mexico's coast as of 1 p.m ET, moving east at around 5 mph with sustained winds of 80 mph. The NHC projects that Polo could become a major hurricane by Wednesday as it tracks parallel to the Mexican coast. Moisture from Polo is already moving into the Southwest, with monsoon thunderstorms and heavy rain expected across New Mexico from Tuesday through Thursday.

The NHC has issued a Tropical Storm Watch from Tecpan De Galeana to Punta San Telmo, warning residents of possible tropical-storm-force winds and torrential rainfall. Officials expect between four and eight inches of rain along parts of the Mexican coast, with isolated areas receiving up to 12 inches—enough to cause life-threatening flooding and mudslides, especially in mountainous regions. Coastal Oaxaca, Colima, and Jalisco could also see three to six inches of rainfall through Thursday, with dangerous surf and rip currents likely to develop as Polo strengthens.

Polo’s structure is compact but powerful, with satellite imagery indicating rapid intensification fueled by warm ocean waters and favorable atmospheric conditions. While current forecasts keep Polo’s core offshore, there is uncertainty about its exact track, and the NHC warns that even slight changes could increase risks to coastal communities.

The moisture from Polo will enhance the Southwest’s monsoon activity. The National Weather Service in Albuquerque said, "Widespread heavy rainfall will lead to a risk of life-threatening flash flooding across much of the state," with the greatest risks occurring from Tuesday onward. A Level 3 out of 4 flash flood threat has been issued for southern New Mexico—including Las Cruces—on Tuesday, shifting north and east to cover Roswell and Albuquerque on Wednesday.

Meanwhile, the Pacific remains very active. The NHC is monitoring four areas of tropical activity, including Tropical Storm Odalys, which is expected to become a hurricane by midweek but poses no immediate threat to land. There is also potential for interaction between Polo and Odalys, which could alter their tracks and increase moisture over the Southwest.

The recent surge in Pacific storms is linked to a strengthening El Niño, which has already produced 18 named storms this season.