Chantal (2007)

A non-tropical low east of the Bahamas gradually organized at the end of July 2007 and became a tropical depression about 210 nautical miles north-northwest of Bermuda around 0000 UTC on 31 July. It strengthened to Tropical Storm Chantal by 0600 UTC 31 July and moved north-northeastward offshore of the U.S. east coast under the influence of a nearby upper-level trough. Chantal was tropical for only about one day before becoming embedded in a frontal zone and losing tropical characteristics; it became extratropical by 0600 UTC 1 August and then accelerated northeastward over the Atlantic and toward and across parts of Newfoundland and beyond into the North Atlantic before merging with another storm on 5 August.

Chantal did not make any landfall while tropical and no watches or warnings were required. Its extratropical remnant passed over the eastern end of the Avalon Peninsula of Newfoundland around 1300–1400 UTC 1 August, producing the heaviest impacts there as an extratropical cyclone rather than as a tropical storm.

The maximum sustained winds during Chantal’s tropical phase were 45 knots (about 52 mph), corresponding to a moderate tropical storm, and the best-track minimum central pressure was 994 mb at 0000 UTC 1 August. After becoming extratropical, the cyclone intensified further, with analyses showing winds near hurricane force over the north Atlantic (maximum extratropical wind estimates up to 60 kt in the post-tropical phase).

The extratropical cyclone produced very heavy rainfall over parts of southeastern Newfoundland, with totals approaching 8 inches over portions of the Avalon Peninsula, leading to severe flooding in some areas. No specific storm surge measurements are listed in the report for U.S. locations, and no coastal surge warnings were issued for the tropical phase since Chantal remained offshore.

There were no reports of damage or casualties directly associated with Chantal while it was a tropical cyclone. Flood-related damage did occur in southeastern Newfoundland from the post-tropical storm’s heavy rains. Forecasts had limited lead time because Chantal was short-lived, but official track and intensity forecasts performed reasonably well for the few advisories issued; the system was first mentioned in the Tropical Weather Outlook about 56.5 hours before genesis.