A flash flood watch remains in effect through Friday evening.  The watch continues for Dallas, Collin and counties to the west.  
A moist tropical air mass is in place over north texas and scattered to numerous showers and thunderstorms are expected today across the flash flood watch area. Showers and thunderstorms will be capable of heavy rainfall…with localized
  rainfall rates of 2 inches per hour possible. Additional  rainfall amounts may exceed 2 inches in isolated areas. Since  the ground is almost saturated from previous rains last  week…runoff will begin quickly and fill small streams and
  other low lying areas rapidly. 

A flash flood watch means that conditions are favorable for heavy rain which may lead to flash flooding.