Alberto meandering off the US Coast - 5/20/12
Good morning and welcome to my tropical weather update for Sunday, May 20th, 2012. The main story today is Tropical Storm Alberto, currently located at 31.7°N 79.3°W. Maximum sustained winds are at 50mph with higher gusts, and Alberto is moving west-southwest at 6mph. Satellite shows that Alberto is a fragile and small system, which last night out of no where became a 60mph Tropical Storm. That can happen often with these small storms, even in an unfavorable environment, they can wind up fast and they can also loose steam fast as Alberto also did overnight.
(figure 1. Current satellite image of Alberto)
Where will Alberto go?
Alberto is currently moving WSW, but that direction is expected to change as Alberto interacts with a non-tropical low and a front oncoming towards the system. It's forward speed should decelerate and become stationary by 2pm or so as a deep-layered ridge of the United States weakens, after that Alberto should generally begin to move in a more northerly direction by later today and should eject to sea with only a novice to shipping.
(figure 2. Current NHC track of Alberto)
How strong will Alberto get?
Alberto has probably peaked in intensity. It is rare to get May storms as it is, but Alberto was in terms of pressure yesterday at 995mb the strongest May tropical cyclone since Hurricane Alma in 1970. Alberto is a small system however, and it is more acceptable to things such as slight increase of wind shear which is quite prudent over the Atlantic in May. Alberto's intensity will also be hampered by two non-tropical lows to the north and soon to be the east of the system that will begin to interact with Alberto.
(figure 3. Intensity model forecast of Alberto)
Is Alberto's formation a signal of an active hurricane season?
In short - not really. Alberto is a one-off cyclone, as 2009 also had a tropical cyclone off the East Coast in May (unnamed) and that season did not have active season at all. These freak systems that develop non-tropically are hard to get and can really happen anytime of the year. If Alberto had developed in the Caribbean, this would be a different story as it would show that shear in the Caribbean would be far below average than it should be for this time of year. Alberto does only to boost the final count this year.
I will have an update tomorrow afternoon.