Developing a Forecast Tool for Cloud-To-Ground Lightning in the North Central and Northeast United States

Cloud-to-ground (CG) lightning is a hazard to the Air Force for both air and ground operations. Forecasting CG lightning is a necessary and extremely important requirement for Air Force meteorologists and forecasters. The 15th Operational Weather Squadron requested a forecast tool capable of predicting CG lightning within a 25 and 10 nautical mile radius of the 13 military locations in their area of responsibility. To fulfill their request, forecast decision tools were created using a Classification and Regression Tree (CART) data analysis program. Four decision trees were produced for each location using the period of record from March through September, 1993 to 2002. CART compared the upper air stability indices and surface data at 12-hour intervals with CG lightning data occurring within the next 12 hours to determine prediction rules. Data from 2003 were used as independent verification of the decision trees.