Tropical Storm Rosa was the first eastern North Pacific tropical storm to develop during the month of November since 2000. The 23rd tropical cyclone and 17th named storm of the 2006 Pacific hurricane season, Rosa developed from a tropical wave that emerged off the west coast of Africa on October 22. The wave traversed the Atlantic Ocean and entered the Pacific Ocean on November 3. Thunderstorm activity began to increase, and it was designated Tropical Depression Nineteen-E on November 8. After fluctuations in organization and intensity, the depression was upgraded to Tropical Storm Rosa on November 9. Persistent wind shear inhibited further intensification, and quickly weakened the storm into a tropical depression on November 10.