The National Hurricane Center upgraded Hurricane Rina to a Category 3 storm on Thursday, increasing the number of major storms in 2011.
The 2011 hurricane season was the third most active season on record, tied with 1887, 1995 and 2010 with 19 named storms, 7 hurricanes and 4 major storms after Rina was upgraded.
Each year after hurricane season ends, the NHC conducts post-storm analysis of all systems that developed during the season. This year they found enough information to upgrade Hurricane Rina from a Category 2 to a Category 3 storm, making it a major hurricane.
A major hurricane is classified as a category 3 or higher. A category 3 has winds from 111-130 mph; Rina peaked at 115 mph.
Rina formed on October 23rd in the western Caribbean Sea and moved toward the Yucatan Peninsula before quickly weakening to a tropical storm prior to landfall. The storm dissipated rapidly and the last advisory was written on October 28th.
According to the post-analysis, Rina reached Category 3 status on Oct 25 and peaked the following day with winds of 115 mph.
The upgrade is based primarily on a NOAA SFMR (Stepped Frequency Microwave Radiometer) of 103 kt on October 25th with another SFMR reading of 98 kt taken a few hours later by the Air Force Reserve.
At the time, the peak SFMR reading was flagged as questionable, so a more conservative flight level wind adjustment factor that supported 95 kt was used. The post-analysis revealed that the SFMR data were not contaminated and Rita was upgraded to a Category 3.