19 Jul 2023 | 05:16 AM UTC
Pacific Ocean: Tropical Storm Calvin tracking westward toward Hawaii as of the evening of July 18 /update 3
TS Calvin tracking westward in the central Pacific Ocean evening of July 18. Close approach to Hawaii, US, late July 18-early July 19.
Event
Tropical Storm Calvin is tracking westward in the central Pacific Ocean the evening of July 18. As of 17:00 HST, the system's center of circulation was approximately 285 km (175 miles) southeast of Hilo, Hawaii.
Forecast models indicate that the storm will weaken slightly as it tracks generally west-northwestward and passes just south of Hawaii/Big Island late July 18-early July 19. After passing the Hawaiian Islands, Calvin is forecast to weaken into a tropical depression and then transition into a post-tropical cyclone as it continues to track west-northwestward and dissipate over the central Pacific Ocean July 19-21. Some uncertainty remains in the track and intensity forecast, and significant changes could occur over the coming days.
As of the evening of July 18, authorities have issued a tropical storm warning for Hawaii County. Tropical storm-force winds are likely in the warning area from the evening of July 18. Rainfall totals of 10-20 cm (4-8 inches) are forecast along the windward slopes and southeast flank of the Big Island of Hawaii, 7.5-15 cm (3-6 inches) across the windward areas of Maui, and 5-10 cm (2-4 inches) across the rest of the state through July 20. The heavy downpours could trigger flooding in low-lying areas and landslides on unstable slopes. Heavy swells generated from Calvin are likely to impact the main Hawaiian Islands late July 18. These swells will probably cause life-threatening surf and rip current conditions. The National Weather Service has also issued flood watches, wind advisories, high surf warnings, gale watches, and small craft advisories across parts of Hawaii and its surrounding coastal waters.
Authorities in Hawaii County have established eight emergency shelters. Waipio Valley Access Road is open to residents and farmers only to aid in potential evacuations. Authorities are urging residents to stay off the roads if possible and have warned that the southeast side of the island, particularly Kawa Flats in the vicinity of Whittington Beach Park and Honu‘apo, are known for flooding. Officials have suspended Hele-On bus services July 18-19, closed all parks, and canceled camping permits islandwide July 18-19.
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 may increase the incidence of 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.
