The weekly weather discussion at Stony Brook University reviewed the interesting weather over the past week and discussed the increased activity in the Tropics.
On Tuesday, September 3, 2013 there was a cold frontal passage that coincided with some severe thunderstorms over Eastern Long Island. There was a report of severe hail (greater than 1.00 inch in diameter) in Hampton Bays. The storms were caused by a moist and unstable air mass that was set up over Long Island. However, the unstable air needed a lifting mechanism to tap into that instability and cause the air to rapidly rise and for storms to form and that mechanism was a cold front.
A tropical storm (Gabrielle) had formed in the Atlantic but didn't last long because it moved over the mountainous island of Hispaniola which was too harsh to keep the storm going. Recall that tropical cyclones get their energy from warm, ocean waters and need to maintain their stiff vertical structure which mountains would disrupt.
If a hurricane (not just a tropical storm, of which there have been 7) does not form by September 11th, then the previous record set for latest first hurricane formation in the Atlantic will be broken. There are a couple of areas of tropical convection that may organize into a tropical storm and subsequently a hurricane with time. Of special interest is a fresh wave of convection coming off the coast of Africa. The National Hurricane Center is paying strict attention to it because the environment in which the disturbance is moving is favorable for its development. Low shear (wind speed or direction changing with height that would disrupt the storm's vertical stiffness of its center), high moisture (food for clouds) and high heat content from the warm ocean waters (drives the winds and strengthening of intensity of the storms) are all important and expected to be present in the coming week for this wave. Stay tuned!