User:Iune/Blanca

The origins of Hurricane Greg are believed to be the southern section of the tropical wave that created Atlantic tropical storm Emily that crossed Central America between August 31 and September 1. Thunder storm activity became more concentrated and banding had formed by September 5. Based on this, it is estimated that the disturbance became Tropical Depression Twelve-E at 1200 UTC (5 a.m. PDT) on September 5 while very close to Manzanillo, Mexico. Operationally, however the National Hurricane Center (NHC) began issuing advisories for the storm four hours later.

At that time, the depression had good convective banding and outflow and was predicted to become a tropical storm within 12 hours and reach minimal hurricane intensity within two days while undergoing a northwestern motion. Six hours later, the depression was upgraded to a tropical storm and named Greg. Greg slowly strengthened and had winds of 50 mph (80 km/h) by the next morning. At this time, it was anticipated that Greg would start to undergo a west-northwestern track within 24 hours due to a anticyclone over the southwestern United States. Later that morning, Mexican radar noticed an eye forming as the storm reached upper tropical storm strength. That afternoon, even though the storm now had a ragged appearance, the National Hurricane Center upgraded Tropical Storm Greg to a hurricane. In post season analysis, it was determined that Greg had become a hurricane three hours earlier.