Invest 91L (July 2011)

Invest 91L was a wave that was invested late July. After moving off the African coast on July 25, the wave never gained much thunderstorm activity. It soon acquired more spin and was invested on July 28 in the middle of the Atlantic Ocean. The wave continued to strengthen until it formed into Tropical Storm Emily late on August 1.

Meteorological history
On July 25, an area of thunderstorms part of the ITCZ moved off the Senegal coast into the Atlantic Ocean. The once compact thunderstorm complex dispersed and spread to a greater area, now filled with mostly low clouds. At the time, dry air from the Saharan Air Layer affected the system, preventing it from organizing. Two days later, however, the disturbance began to acquire spin. Additonal convection formed from the wave, and the National Hurricane Center (NHC) noted the large organized area, giving it a "low" 20% chance of formation late on July 28. The wave was designated as Invest 91L shortly after. Invest 91L continued to become better defined as it moved westwards. Thunderstorm activity soon collected towards the center, and the NHC gave the invest a 70% chance for formation. As the disturbance neared the Lesser Antilles, multiple aircraft recons and Hurricane Hunter aircraft examined the storm, failing to find a closed circulation in Invest 91L. Soon, the storm became elongated due to shear, and the most westerly part of the system detached and formed its own wave as Invest 91L continued to move west.

Convection abruptly exploded to the east of the storm mid-day on August 1. A wall of thunderstorms formed as it neared the Antilles, stretching from Guadeloupe to Barbrados. Hours later, the exposed circulation center made landfall on Dominica. As it did so, thunderstorm activity formed over the circulation, hiding it from satellite imagery. The wave progressively became better defined and was designated as Tropical Storm Emily late on August 1.

Impact
Barbados: Grantley Adams Int'l Airport (located on Barbados' south coast) reported light thunderstorms. Dominica: Invest 91L made landfall towards the south of Dominica. Continuous thundershowers caused some street flooding in Roseau, the capital of Dominica. The invest, which already had tropical storm force winds, forced strong wind gusts over the island.

Grenada: As a result of the storm, Grenada had in some places up to 3 inches of rain, which caused flooding in many locations. Landslides were also caused as a result of the heavy rains. Strong gusts knocked trees over in addition to the flooding.

Martinque: In preparation for the storm, Martinque postponed its annual Tour des Yoles Rondes. The flooding caused landslides, and 4 families were forced to evacuate.

St. Lucia: Power was cut off for approximately 30 minutes as a result of the storm.

St. Vincent and the Grenadines: Thunderstorms caused flooding in many places, including a measurement of 5 inches of rain at a local meteorological office.