This morning we have a very unusual set up for this time of the year, a strong area of low pressure spinning over the Great Lakes region pretty much stalled out. This is leading to a Southerly flow up the east coast and importing a tropical air mass and an unstable air mass right into the region as we are in the warm sector of this storm.
As this tropical moisture flows in you can see rain and thunderstorms are filling into the region from the SW and also storms forming over SE NJ which are moving NNE . The blob of rain and storms over Eastern PA will slowly shift east through the day and showers and thunderstorms will continue to fill into the area , it will also be very humid. Highs in the upper 70s to low 80s are expected but with dew points in the low 70s, heat indexes will range from the mid to upper 80s
Very heavy rain and strong to severe thunderstorms are expected as the atmosphere is very unstable. In any storms, very heavy rain, dangerous lightning and gusty winds possibly exceeding 40 mph are expected. In Northern NJ and NE PA where we have some wind shear, an isolated tornado cannot be ruled out.
Flash flooding will also be a concern as heavy rains will train over the same areas for quite some time. These thunderstorms will continue periodically through the night before becoming less widespread tomorrow, although scattered showers and storms are still expected through the early afternoon hours.
Stay alert, be ready for changing weather conditions and stay tuned to local forecasts for any advisories or warnings that may be issued.