It’s not the best time of year for a heavy rain event, smack in the middle of the July 4th holiday weekend, but it appears there’s the potential for some torrential downpours tomorrow.
A cold front will approach from the west and a significant amount of moisture will stream north. In addition, very weak winds from the ground up through 35,000 feet, will result in very slow movement of thunderstorms that do develop.
Here’s a 18z NAM BUFKIT forecast sounding from BDL. Ingredients for heavy rain are there with instability, large amounts of moisture, and weak steering flow.
If numerous thunderstorms are able to form along a stalled surface front there is a risk for flash flooding in some locations. Not every town is going to see big downpours tomorrow but some certainly will.
Severe weather will not be widespread with little wind shear and only modest instability. If the instability winds up being more impressive than currently forecast (steeper mid level lapse rates and/or more morning sunshine) than there is the risk for pulse severe thunderstorms producing downbursts.