Alberto, the first storm of this 2012 Atlantic Basin Hurricane Season, formed on May 19th...12 days before the official start to the season which is June 1st. Alberto formed off the South Carolina Coast...reaching tropical storm strength. It's expected to remain over the Western Atlantic and not make a landfall in the U.S.
Alberto stunned many people because they felt it's too early to have a tropical system. However, it is not unusual for a tropical cyclone to form before the official "calendar" start to Hurricane Season. June 1st thru November 30th is just a window of time when, climatalogically speaking, most tropical systems form. However, this in-no-way means that tropical cyclones won't form before June 1st or after November 30th.
A look back at recent history shows that pre-season tropical cyclones aren't unheard-of. In 2009, there was Tropical Depression #1 that formed on May 28th off the Mid-Atlantic Coast (It fizzled out the next day). In 2008, Authur formed on May 31st in the Western Caribbean...and it reached Tropical Storm strength. In 2003, Ana formed well before the start of Hurricane Season on April 18th in the Western Atlantic...becoming a Tropical Storm. In 1981, Arlene formed on May 6th in the NW Caribbean...becoming a Tropical Storm.
Post-Season tropical cyclones are also possible. Here's a list since the year 2000: In 2007, Olga formed on December 10th east of Puerto Rico...becoming a tropical storm (it did make it into the Central Gulf...then it fizzled, never reaching the Gulf Coast). In 2005 (which was a historic year), there were so many tropical systems that the offical Hurricane List of names was surpassed...and the Greek alphabet had to be used to name storms. So, Zeta formed on December 30th in the east/central Atlantic...becoming a tropical storm. This storm held together until January 7th of the new year! Also...In 2003, two storms formed after the calendar end to hurricane season (Nov. 30th): Odette formed on December 4th in the Caribbean...and Peter formed on December 7th in the Eastern Atlantic. Both did reach Tropical Storm Strength.
So, the point is to remember that Mother Nature doesn't always operate based on what the calendar says. If the atmospheric conditions are right...Tropical cyclones can develop out of season, Tornadoes can spawn in the Winter, Snow can fall in Spring, and it can be Cold in the Summer...you get my drift:-) Just respect the weather, and watch The Weather Authority to get the info you need to keep up with Mother Nature.
Meteorologist Deitra Tate