There is an Air Quality Alert in effect for Long Island and NYC today, due to elevated levels of ozone. In addition, there is a Heat Advisory in effect for today and tomorrow for the tri-state area, with the exception of Suffolk County. The combination of temperatures in the low 90's and moderate to high levels of humidity will make it feel like 95 to 100 degrees in the areas covered by the Heat Advisory.
A quick update on Tropical Storm Don: The storm has weakened to an open wave, and it's not expected to pose any significant problems.
Today and tomorrow should be hot with temperatures in the mid 80's to low 90's, with the cooler temperatures on the south shore and east end. There is only a slight chance of a late afternoon or evening thunderstorm. A better chance of showers and thunderstorms is for late Thursday night into Friday morning with the passage of a cold front. That will lead to nice weather on Friday, although it will still be very warm; however, humidity levels will be lower. Clouds will be on the increase on Saturday, and showers may arrive sometime in the afternoon or evening. At this time, Sunday looks like periods of showers and thunderstorms.
The following image is from the GFS model, and it's showing showers in the area for Sunday morning:
Image from tropicaltidbits.com