Azores storm 92L unlikely to develop; East Pacific hurricane season begins

The hybrid low pressure system with both tropical and extratropical characteristics that formed Saturday over the far Eastern Atlantic, about 450 miles southwest of the southern Azores Islands (Invest 92L), has weakened considerably, and is unlikely to become Subtropical Storm Alberto. Wind shear has increased to a very high 25 - 40 knots over 92L today, causing a marked deterioration of the heavy thunderstorm activity. Also not helping is the fact 92L is over cold ocean waters of 68°F (20°C.) This is well below the 26°C usually needed for a tropical storm to form. Satellite estimates of 92L's winds were 35 mph at 7:45 am EDT Monday, according to NOAA/NESDIS. NHC estimated that 92L had top winds of 40 mph at 8 am EDT Monday, down 10 mph from Saturday's peak. Wind shear is expected to remain very high and water temperatures will cool as 92L moves northeast towards the Azores Islands on Tuesday and Wednesday, and the chances of the storm developing into a subtropical or tropical cyclone are near zero percent.


Figure 1. True color satellite photo of Invest 92L taken at 8:35 am EDT Monday May 14, 2012. Image credit: NASA.

Eastern Pacific hurricane season begins
The first tropical depression of the 2012 hurricane season has formed this morning in the Eastern Pacific, and it comes one day before the official May 15 start of the Eastern Pacific hurricane season. Tropical Depression One-E is located about 645 mi south of Manzanillo Mexico, and is headed west, away from any land areas. Wind shear is a low 5 - 10 knots, ocean temperatures are a warm 29°C, and TD One-E has a good chance of becoming the season's first tropical storm by Tuesday. It is unusual to get a tropical storm forming this early in the year in the Eastern Pacific; since record keeping began in 1949, there have only been two that have formed by May 15--Hurricane Alma of 1990, and an unnamed 1996 storm. TD One-E will not live for long--the storm is headed towards a region with high wind shear and cooler waters that should be able to destroy it late this week.

Only weak potential for an Atlantic system developing over the next week
The models have backed off on their predictions of a potential subtropical storm developing over the Western Caribbean or waters near Florida this weekend, though it is possible we might see something develop along an old cold frontal boundary between the Bahamas and Bermuda. If such a storm did develop, it would likely move northeast out to sea.

Jeff Masters