Forecast uncertainty is loosely proportional to the latent heat release (aka rainfall) in events like this, which is another way of saying these events can be unpredictable.

At left is a short range HRRR forecast (7 hour) and at right is the radar. Expect some surprises. #nywx pic.twitter.com/oPDCBnjOoM

— Nick P Bassill (@NickPBassill) July 9, 2023