Hawaii island under tropical storm watch as Calvin approaches

A tropical storm watch was issued this morning for Hawaii island and its surrounding waters as Calvin becomes the first tropical cyclone in the Central Pacific for the 2023 hurricane season.

A watch means that tropical storm conditions are possible within the next 36 to 48 hours.

The National Weather Service has also issued a flood watch for Maui County and Hawaii island from Tuesday evening through Wednesday afternoon.

Before 5 a.m. today, the Central Pacific Hurricane Center on Oahu said Tropical Storm Calvin, with maximum sustained winds of 50 mph was about 920 miles east of Hilo and 1,120 miles east-southeast of Honolulu, moving west at 18 mph. This general motion is expected in the next few days, officials said. Tropical storm-force winds extend outward up to 105 miles from the center.

“Calvin is expected to approach the main Hawaiian islands on Tuesday and early Wednesday,” the CPHC said this morning.

Forecasters said that total rainfall amounts of 4 to 7 inches are possible along windward areas of the Big Island from Tuesday night into Thursday, with 1 to 4 inches expected elsewhere in the state. “This rainfall could lead to localized flash flooding and mudslides,” officials said.

Calvin “will produce periods of heavy rainfall over all islands in Maui and Hawaii Counties from Tuesday evening through Wednesday afternoon. Excessive rainfall may lead to flooding conditions and landslides over steep terrain, especially along east and southeast facing slopes,” officials said.

In addition, swells generated by Calvin are expected to begin reaching the main islands over the next couple of days, causing life-threatening surf, they said.

According to the latest five-day track, Calvin will move near or pass just south of the Big Island early Wednesday, then pass south of the other islands as a tropical depression into Thursday.