From OKX discussion:
Timing of onset of convection looks to be late morning into
early afternoon for the Lower Hudson Valley, during the early
afternoon for much of the remainder of the area, with perhaps
Eastern Long Island and Southeast Connecticut not getting the
onset of convection until closer to mid afternoon (about 3PM
local time).
The convection looks to end by mid evening, about 10 PM for
Lower Hudson Valley, Northeast NJ, and NYC and closer to
midnight to 1AM farther east. Dry weather returns thereafter
into early Sunday as the cold front moves farther south of Long
Island.