1996 PRELIMINARY REPORTS

Tropical Storm Arthur (TS)
Hurricane Bertha (3)
Hurricane Cesar (1)
Hurricane Dolly (1)
Hurricane Edouard (4)
Hurricane Fran (3)
Tropical Storm Gustav (TS)
Hurricane Hortense (4)
Hurricane Isidore (3)
Tropical Storm Josephine (TS)
Tropical Storm Kyle (TS)
Hurricane Lili (3)
Hurricane Marco (1)

a. Synoptic History

Hurricane Dolly formed from a tropical wave of large lateral extent that moved from the west coast of Africa to the central Caribbean Sea during 9-18 August 1996. Although the wave generated deep convection when it emerged from Africa, there was little accompanying thunderstorm activity for much of its passage across the tropical North Atlantic Ocean. Deep convection redeveloped when the wave reached the eastern Caribbean, but did not persist in a concentrated pattern until the system was south to southwest of Jamaica on the 18th-19th. A low- to mid-level cyclonic circulation was then detected in data obtained during a NOAA research flight to study the development of tropical cyclones. Satellite analysts indicated that the system was too weak to classify using the Dvorak technique late on the 18th, but they calculated Dvorak T-numbers of 1.5 and 2.0 on the afternoon of the 19th. By mid-afternoon on the 19th, the first center "fix" by reconnaissance aircraft was made and data from the plane, satellite, and a ship that reported 52 mph at 1800 UTC were used to estimate that the tropical depression stage began with a poorly-defined circulation center near 0600 UTC on the 19th, and that the depression became Tropical Storm Dolly a little more than six hours later.

The tropical cyclone developed near or just south of a mid- to upper-level anticyclone. In that environment, Dolly strengthened on the 19th and 20th and moved toward the west-northwest at a speed that decreased from 17 mph to about 9 mph. Convection became better organized near the circulation center on the 20th and, just before making landfall on the Yucatan peninsula to the northeast of Chetumal, Dolly became a hurricane. It weakened back to a tropical depression and slowed to about 6 mph during its 24-hour passage over the peninsula, and satellite pictures showed the center of cloud rotation displaced to the south of the estimated surface circulation center.

Gradual restrengthening began a few hours after the surface center arrived over the Bay of Campeche. Dolly regained hurricane status and was at it strongest, with 81 mph winds and a central pressure of 989 mb, when it accelerated to 17 mph and made its final landfall about midway between Tuxpan and Tampico near 1800 UTC on the 23rd.

Dolly then weakened and, as a tropical depression, crossed central Mexico. It continued to generate areas of deep convection and, likely, heavy precipitation even while its surface center dissipated over the eastern North Pacific Ocean on the 25th.

b. Meteorological Statistics

The only available official observations of at least tropical storm force winds from a surface land site came from Tampico, Mexico. There, 10-minute winds of 46 mph with gusts to 69 mph occurred at 1045 UTC and 1145 UTC on the 23rd. An amateur radio report of a gust to 68 mph was received from Tampico.

1. Rainfall Data

c. Casualty and Damage Statistics

There were 14 deaths attributed to Dolly; 14 in Mexico.

According to newspapers reports, Hurricane Dolly was responsible for fourteen deaths in Mexico--including six in Veracruz (all drowned), three in Nuevo Leon, and one each in Pueblo Viejo and Monterrey. Two people were missing in Nuevo Leon.

Those reports also indicated hundreds of residences destroyed and 35,000 people displaced. Severe damage occurred in Tuxpan, Tamiahua, Pueblo Viejo, Platon, Panuco, Tampico Alto and elsewhere along the coast of northeast Mexico. A river overflowed its banks causing damage in Pueblo Viejo. A large area of farm land was lost to flooding in Quintana Roo on the Yucatan peninsula.

Rain prompted evacuations in the southern part of the state of San Luis Potosi. About 6500 people were evacuated from low-lying zones of Tampico.

Widespread communication and power outages were noted as far west as Mazatlan.