Urban heat islands and summertime convective thunderstorms in Atlanta: three case studies

Data from both 27 sites in the Atlanta mesonet surface meteorological network and eight National Weather Service sites were analyzed for the period from 26 July to 3 August 1996. Analysis of the six precipitation events over the city during the period (each on a di!erent day) showed that its urban heat island (UHI) induced a convergence zone that initiated three of the storms at di!erent times of the day, i.e., 0630, 0845, and 1445 EDT. Previous analysis has shown that New York City (NYC) e!ects summer daytime thunderstorm formation and/or movement. That study found that during nearly calm regional #ow conditions, the NYC UHI initiates convective activity. Moving thunderstorms, however, tended to bifurcate and to move around the city, due to its building barrier e!ect. The current Atlanta results thus agree with the NYC results with respect to thunderstorm initiation. ( 1999 Elsevier Science Ltd. All rights reserved.