Pacific Ocean: Tropical Storm Orlene tracking northward as of early Oct. 1 /update 1

Event

Tropical Storm Orlene is tracking northward over the eastern North Pacific Ocean early Oct. 1. As of 03:00 MDT, the system's center of circulation was approximately 380 km (235 miles) south-southwest of Cabo Corrientes, Jalisco State.

Forecast models indicate that the storm will strengthen into a Category 1 hurricane as it tracks north-northeastward towards the western coast of Mexico Oct. 1-Oct. 2. The system is expected to weaken back into a tropical storm as it continues to track north-northeastward off the coasts of Jalisco and Nayarit states Oct. 2-3, before making landfall south of Mazatlan in southern Sinaloa State around 12:00 Oct. 3. The storm is forecast to weaken into a tropical depression as it tracks over land across southern Sinaloa and into western Durango states Oct. 3-early Oct. 4. Some uncertainty remains in the track and intensity forecast, and significant changes could occur over the coming hours and days.

As of early Oct. 1, authorities have issued the following coastal watches and warnings in relation to the storm:

Tropical Storm Warning

• The coast of mainland Mexico from Playa Perula to San Blas

Hurricane Watch

• Las Islas Marias

• The coast of mainland Mexico from San Blas to Bahia Tempehuaya

Tropical Storm Watch

• The coast of mainland Mexico from Manzanillo to Playa Perula

Authorities will likely issue new warnings or update existing advisories throughout the system's progression in the coming days.

Hurricane conditions are possible in Las Islas Marias from late Oct. 2 and tropical storm conditions are possible along portions of the west-central and southwestern coast of mainland Mexico from Oct. 2. Forecast models predict rainfall totals through late Oct. 3 of 7.5-12.5 cm (3 to 5 inches), with localized maximums of up to 25 cm (10 inches), across portions of southwest Mexico. The heavy rainfall could trigger flash flooding and landslides in affected areas. Storm surge could cause coastal flooding in areas covered by watches and warnings. Large swells generated by Orlene will affect the coast of southwestern Mexico and the far southern Baja California Peninsula Oct. 1-2. Mexico's National Meteorological Service (SMN) has warned that the system will bring very strong punctual rains to parts of Nayarit, Jalisco, Colima, and Michoacan states, as well as strong winds and rough seas to the coasts of Colima and Jalisco Oct. 1.

Ahead of the approach of Orlene, authorities in Sinaloa State have released water from dams across the state to reduce the risk of flooding and established around 120 emergency shelters for those unable to safely shelter from the storm at home.

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.

The inclement weather could trigger localized business, transport, and utility disruptions and render some bridges or roadways impassable. Flight disruptions at regional airports and temporary closures of ports 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.

Advice

Activate contingency plans in areas where officials forecast tropical storm conditions. Heed any evacuation orders that may be issued. Use extreme caution in low-lying coastal areas and near streams, creeks, and other waterways due to the potential for severe flooding and storm surge. Stockpile water, batteries, and other essentials in advance. Charge battery-powered devices when electricity is available; restrict the use of cellular phones to emergencies only. Power down mobile devices when not in use. Keep important documents and necessary medications in waterproof containers. Observe strict food and water precautions, as municipalities could issue boil-water advisories following flooding events. Take precautions against insect- and waterborne diseases in the coming weeks.

Plan accordingly for protracted commercial, transport, and logistics disruptions in areas in the path of the storm, especially if vital infrastructure is damaged. Seek updated information on road conditions before driving or routing shipments through areas where flooding has occurred. Confirm flights before checking out of hotels or driving to the airport; clearing passenger backlogs may take several days in some locations.

Resources

US National Hurricane Center
National Weather Service
Mexican Meteorological Service