Tropical Cyclone Bulletin no.7
WATCH MESSAGE NO. 1
Date: Friday August 21, 2020 Time: 11:52 local time
Weather forecast Saba & Sint Eustatius by KNMI for the Caribbean Netherlands
Key Messages / Watches and warnings:
- A Tropical Storm Warning is in effect for Tropical Storm Laura.
- Tropical Storm Laura is expected to pass 1-6 miles (2-9 km) S of St Eustatius/Saba on Friday August 21 21:00 AST
- Tropical Storm Force winds are expected. Max. sustained winds around 75 km/h, gusts up to 90 km/h.
- Heavy showers are likely. Accumulated rainfall 25-75 mm, small risk up to 125 mm. There is a risk of mudslides and flash floods.
- 8-12 ft high waves are expected from late Friday into the night towards Saturday
Effect on local conditions
Winds:
Tropical Storm Force winds are expected with maximum sustained winds of 75 km/h (40 kts) and wind gusts up to 90 km/h (50 kts). Winds will come from a northeasterly direction on Friday evening, ending up from a south to southeasterly direction on Saturday. Outside this period normal conditions are expected.
Seas:
Significant wave heights of 3-5 ft are expected. In case of Tropical Storm Conditions significant wave heights may increase to 6-9 ft on Friday, to 8-12 ft in easterly- to northeasterly swell in the night towards Saturday, decreasing again to 5-7 ft on Sunday.
Rainfall:
The Tropical Storm is expected to produce heavy showers and thunderstorms with 25-75 mm (1 to 3 inches) of rain with isolated maximum totals of 125 mm (5 inches) from Friday evening through Saturday. Flash floods and mudslides are possible.
Local authorities and residents of Saba and St. Eustatius are advised to continue monitoring the further progress of this weather system and to take all necessary measures to safeguard life and property.
Center's latest and forecast positions:
SABA:
Till Wed Aug 26 08:00 AST, the nearest position is estimated at:
Fri Aug 21 22:00 AST 17.5N 63.2W Tropical Storm 9 km (6 mi) S of Saba
Fri Aug 21 11:00 AST 17.0N 60.2W Tropical Storm 330 km (205 mi) ESE of Saba
Fri Aug 21 20:00 AST 17.4N 62.7W Tropical Storm 62 km (39 mi) ESE of Saba
Sat Aug 22 08:00 AST 18.3N 66.0W Tropical Storm 302 km (187 mi) WNW of Saba
Sat Aug 22 20:00 AST 19.2N 69.5W Tropical Storm 683 km (425 mi) WNW of Saba
ST. EUSTATIUS:
Till Wed Aug 26 08:00 AST, the nearest position is estimated at:
Fri Aug 21 21:00 AST 17.5N 63.0W Tropical Storm 2 km (1 mi) S of St. Eustatius
Fri Aug 21 11:00 AST 17.0N 60.2W Tropical Storm 300 km (186 mi) E of St. Eustatius
Fri Aug 21 20:00 AST 17.4N 62.7W Tropical Storm 31 km (19 mi) ESE of St. Eustatius
Sat Aug 22 08:00 AST 18.3N 66.0W Tropical Storm 332 km (207 mi) WNW of St. Eustatius
Sat Aug 22 20:00 AST 19.2N 69.5W Tropical Storm 714 km (444 mi) WNW of St. Eustatius
Definitions:
TROPICAL STORM WARNING: A warning for tropical storm conditions, including sustained winds within the range 63-117 km/h (39-73 mph) (34-63) knots are expected in specified areas in 36 hours of less.
Next bulletin: Friday August 21, 2020, 17:52 local time