The Pacific tropical cyclone season starts on May 15th -- and on schedule, the first tropical system of the season formed yesterday to bring an early kickoff to the tropical festivities. Tropical Storm Aletta is working westward into the open waters of the Pacific, with another day or perhaps two days of strengthening or steady state conditions in it before cooler water farther west in the ocean seals its fate as a tropical entity.
May tropical cyclones in the Pacific are not unusual -- a tropical storm last formed in May in the Pacific in 2010 and before that, one formed in 2008. Usually the May tropical storms track towards Mexico or Central America -- Aletta will not.
One area of thunderstorm activity that might impact Central America or Mexico is this large area of disturbed weather off of the southern coast of Mexico in the Pacific Ocean. This area of thunderstorm activity has been "model hyped" for the past several days to become some sort of tropical entity that tracks from the Caribbean up across Florida and into the Atlantic. Recently, modeling from the Euro has shifted the threat to a more Pacific-based setup, with the potential for a second tropical system in the Pacific by this weekend or early next week. The GFS continues to suggest that this area of thunderstorms moves across Central America into the Caribbean and perhaps develop there.
However, most of the upper level modeling shows a better chance of development on the Pacific side of the fence. Whether it develops there, or not at all, remains to be seen, but the Euro is relatively consistent over the past couple of days at developing something south of the Mexican Riviera.
Closer to home, the subtropical/tropical/nontropical low that we talked about earlier this week that was projected to develop off of the Carolinas continues to show signs of doing that in modeling projections. It looks like it may develop on Friday. However, compared to past modeling the feature is showing up weaker and may have less of an impact on our weather than what was discussed a while back...and if it is a factor, it won't be until Monday or Tuesday of next week. We'll keep an eye on that.