An analogue is a means of predicting future conditions by comparison with historical situations. In terms of ECWS, two storms are analogues of each other if they follow a similar track and have similar surface pressures during their lifetimes. Based on analyses of numerous historical storms and surges, an analogue index was computed. The index weights storm location (track) 55% and surface pressure 45% provided the best means of identifying storms that prodcued similar ssurge. In other words, storms with similar analogue indices often resulted in similar surges at gauge locations along Long Island. By comparing the forecasted track and pressure characteristics of an impending storm with all storms in the historical database, the closest match can be found and the associated surge used as a forecast of the potential surge impacts from the current storm.