A drooping Tropical Storm Chantal may pour up to 70 millimetres of rain on parts of Newfoundland when it passes by Tuesday night.

Chantal, the third named storm of the Atlantic hurricane season, is expected to hit as a post-tropical storm.

The storm is forecasted to approach southeastern Newfoundland by Tuesday night and then to move northeast of the Avalon Peninsula by Wednesday afternoon, Environment Canada reported.

Rain is currently falling over the Burin Peninsula and it is expected to continue until the storm passes on Wednesday morning.

By late afternoon, the storm had maximum sustained winds of 85 kilometres per hour and was centred about 200 kilometres south of Halifax.

It was moving northeast at nearly 50 kilometres per hour.

If it slowed down, Environment Canada meteorologist Bob Robichaud said rainfall could top 100 millimetres by Wednesday morning.

"It's certainly not unheard of with these types of systems," he told The Canadian Press.

Environment Canada has issued warnings for the Avalon and Burin peninsulas on the south side of the island.

Such heavy rainfall could created local flooding and treacherous driving conditions, it warned.

Organizers of the Royal St. John's Regatta, a rowing tournament, are trying to decide whether they should delay the event until Thursday.

Chantal formed Tuesday between Bermuda and Massachusetts.

Robichaud described it as an average summer storm during hurricane season.

"This is pretty much par for the course," he said. "Especially now that we're getting into the mid to latter part of summer, the waters are getting progressively warmer and warmer, and we start to see these systems developing more often."

The first named storms of 2007 were Subtropical Storm Andrea, which formed in May, and Tropical Storm Barry, which formed on June 1.

In late May, U.S. forecasters said they expected a busier than normal Atlantic hurricane season, with estimates ranging from 13 to 17 tropical storms and seven to 10 of those becoming hurricanes.

The Atlantic hurricane season, which officially runs from June 1 to Nov. 30, averages 9.6 named storms, with 5.9 of them becoming hurricanes and 2.3 major hurricanes.

With files from The Canadian Press