Hurricane Greg (1999)

Hurricane Greg

Category 1 hurricane (SSHWS/NWS)
Tropical Storm Greg near hurricane strength on September 6
Formed	September 5, 1999
Dissipated	September 9, 1999
Highest winds	1-minute sustained: 75 mph (120 km/h)
Lowest pressure	986 mbar (hPa); 29.12 inHg
Fatalities	10 total
Areas affected	Western Mexico, Baja California Peninsula
Part of the 1999 Pacific hurricane season

Hurricane Greg was the only eastern Pacific tropical cyclone in 1999 to make a direct landfall. Part of the annual hurricane season, Greg originated from a tropical wave that departed Africa in mid-August. The wave entered the eastern Pacific by September 1, steadily organizing over subsequent days to become a tropical depression on September 5. Amid a favorable environment, the cyclone intensified into Tropical Storm Greg a few hours after formation and further organized into a Category 1 hurricane on September 6. Greg paralleled the southwestern coastline of Mexico, where it destroyed over 250 homes, cut-off roads, killed 10 people, and left at least 4,000 more injured. The storm weakened to tropical storm intensity as it moved ashore Baja California Sur, although rain was generally beneficial there. Succumbing to cooler waters and high wind shear, Greg ultimately dissipated over the Pacific on September 9. Its remnants led to thunderstorms across northern California, with only minor impacts.

In mid-August, a tropical wave emerged off the western coast of Africa. The northern portion of the wave led to the formation of Tropical Storm Emily in the Atlantic, while the southern portion of the wave continued westward. It crossed Central America on August 31 and September 1, characterized by a large area of convection and a mid-level circulation. The disturbance traversed southern Mexico before emerging offshore, where it began to interact with a broad area of low pressure that existed in the eastern Pacific for several days prior. Shower and thunderstorm activity became concentrated about a well-defined center, leading to the formation of a tropical depression near Manzanillo, Mexico by 12:00 UTC on September 5. A portion of the tropical wave also combined with monsoonal-like flow across the Bay of Campeche to form Tropical Depression Seven in the Atlantic.