Don (2017)

A tropical wave that moved off west Africa on 12 July developed into Tropical Depression Five around 0600 UTC 17 July 2017 about 630 nautical miles east-southeast of Barbados. The depression became Tropical Storm Don about six hours later and moved quickly westward beneath a mid-level ridge. Don strengthened to its peak late on 17 July but began weakening overnight as dry air and increasing wind shear affected the small system. The storm lost its closed circulation and degenerated into an open tropical wave shortly after 1200 UTC 18 July about 150 nautical miles southeast of Barbados; the remnant wave moved across the Windward Islands late on 18 July and into the Caribbean Sea.

Don did not make any landfalls as a tropical cyclone. Its circulation opened to a wave before reaching the Windward Islands, and there were no reports of sustained tropical-storm-force winds observed on land while Don remained a tropical cyclone. Tropical storm warnings and watches were issued for several islands (including Grenada, St. Lucia, Barbados, and St. Vincent and the Grenadines) as a precaution during 17–18 July.

The storm’s maximum intensity was 45 knots (about 52 mph) with a minimum central pressure of 1005 mb, reached at 0000 UTC 18 July. That intensity corresponds to a weak tropical storm (well below hurricane strength). Reconnaissance data, including SFMR and a dropsonde reporting a 44‑kt surface wind, supported the peak wind estimate.

Storm surge and rainfall impacts were minimal. There were no reports of sustained tropical-storm-force winds at land stations while Don was a tropical cyclone; Hewanorra International Airport on St. Lucia reported a gust to 35 kt (about 40 mph) at 2200 UTC 18 July after Don had already dissipated. The NHC report recorded no notable storm-surge measurements or major rainfall totals tied to Don as a tropical cyclone.

There were no deaths and no damage attributed to Don. Forecasts of Don’s formation had limited lead time: the first mention in the Tropical Weather Outlook came about 30 hours before genesis and the medium (40–60%) 5‑day formation probability was issued only 24 hours prior. Operational advisories continued for about 12 hours after Don had become a wave because of uncertainty about whether the system still had a closed circulation.