A slow moving cold front will approach the Twin Tiers late Friday with showers and thunderstorms likely.  A wave of low pressure will lift north along the front which will help enhance the rainfall.  A Flash Flood Watch has been posted for Chemung and Tioga counties in NY as well as Tioga and Bradford counties in PA.  Rainfall amounts will average 1-2", but localized higher amounts could lead to flash flooding.  Scattered showers will linger into the weekend.