Mexico: Tropical Storm Ileana tracking northward over northern Sinaloa State afternoon Sept. 14 /update 4

Tropical Storm Ileana is tracking northward over northern Sinaloa State the afternoon of Sept. 14, following landfall southeast of Topolobampo Town, Sinaloa State earlier in the day. As of 14:00 MST, the system's center of circulation was approximately 35 km (20 miles) south-southeast of Los Mochis, Sinaloa State.

Forecast models indicate that Ileana will weaken into a tropical depression as it tracks northwestward over northern SInaloa State before exiting into the Gulf of California late Sept. 14. The storm is forecast to transition into a post-tropical cyclone as it tracks northwestward over the central Gulf of California, roughly parallel to the coast before dissipating late Sept. 15. Some uncertainty remains in the track and intensity forecast, and significant changes could occur over the coming hours.

As of the afternoon of Sept. 14, authorities have issued the following watches and warnings:

• Tropical storm warning: Altata in Sinaloa State to Huatabampito in Sonora State

Tropical storm conditions are expected across portions of the warning area in northern Sinaloa and southern Sonora through the afternoon of Sept. 14. Forecast models indicate the system will produce additional rainfall of 7.5-15 cm (3-6 inches) with localized higher amounts up to 25 cm (10 inches) across coastal areas of northwestern Sinaloa State through Sept. 16. Swells generated by the system will affect portions of the Gulf of California coasts of Sinaloa, southern Sonora, and southern Baja California Sur over the coming days. The swells are likely to cause life-threatening surf and rip current conditions.

Schools were closed in Cabo San Lucas and La Paz in Baja California Sur State Sept. 13 ahead of the approach of the storm. Authorities have advised residents to avoid leaving their homes until the storm passes and to find temporary shelters if they are in an area at risk of flooding; dozens of shelters have been opened across the region for those unable to shelter at home. Reports indicate that several roads in Los Cabos are flooded. El Alto International Airport (LPB) in La Paz and Los Cabos International Airport (SJD) both remained operational during the passing of the storm; however, some flights due to arrive at the airports were canceled Sept. 13.

Sustained heavy rainfall could trigger flooding in low-lying areas and those with easily overwhelmed drainage systems. If weather conditions prove hazardous, localized evacuations, flash flooding, and landslides are possible.

Inclement weather could trigger localized business, transport, and utility disruptions and render some bridges or roadways impassable. Flight disruptions at regional airports and temporary port closures are also possible. Stagnant pools of water during and after flooding increase insect- and waterborne diseases, such as dengue fever, cholera, and malaria. Exposure to raw sewage and other hazardous materials mixed with floodwaters poses a serious health threat.