Hurricane Marilyn - Meteorological History

Meteorological History

Marilyn's origins were from a tropical wave that formed off the African coast on September 7. Large, low-level winds were included in the wave's circulation, but little convection existed. The system continued west for a few days at about 19 mph (31 km/h) next to an anticyclonic aloft. On September 12, satellite pictures viewed the disorganized wave and declared it Tropical Depression Fifteen, after convection had increased. Tropical Depression Fifteen strengthened rapidly, becoming Tropical Storm Marilyn six hours later. One day after being named, Marilyn was upgraded to hurricane status, while turning on a more northwesterly track.

For the next few days, Marilyn's track took it towards the west-northwest and to the northwest, due to a weakness in the subtropical ridge. Marilyn was a Category 1 hurricane; it passed 52 mi (84 km) north of Barbados and Martinique. Marilyn passed over Dominica, and just Îles des Saintes and southwest of Guadeloupe on September 14, bringing heavy rains and strong winds with it. Marilyn continued on its northwesterly track, making landfall in the U.S. Virgin Islands on September 15, packing winds of 110 mph (180 km/h), a strong Category 2 strength hurricane. The eyewall, east-southeast of the center of Marilyn, passed over Saint Thomas later that day. After passing over Puerto Rico, Marilyn entered back into the Atlantic Ocean on September 16.

A low had formed near Marilyn, which may have enhanced outflow from the system. An eye formed in the center of Marilyn, and the storm reached a peak intensity of 949 millibars and winds of only 115 mph (185 km/h), a lower-end Category 3 hurricane. At this time, Marilyn was predicted to peak in wind speeds of 120–125 mph (190–195 km/h). Reconnaissance data found a concentric pair of eyewall wind maxima. Marilyn started weakening rapidly, falling from peak-level winds of 141 mph (227 km/h) down to 102 mph (164 km/h). The central pressure also rose up 20 mbars in only 10 hours. This rapid weakening was caused by westerly shear and dry air entrained in the system, a decaying eyewall, and especially cool waters upwelled from the previous powerful storm, Hurricane Luis. As Marilyn weakened to Category 1 hurricane status and moved north-northwest, it passed about 174 mi (280 km) west of Bermuda on September 19. As Marilyn encountered more westerly shear, it weakened to below hurricane status and made its extratropical transition on September 20, centered in the northeastern Atlantic. The remnant circulation continued to erratically move through the central Atlantic Ocean for another 10 days before being absorbed by a frontal low on September 30.

A Hurricane Hunter reconnaissance flight reported hail, which is unusual for tropical cyclones.