Dangerous hot and humid conditions continue through tomorrow with a heat index rising over 100 degrees.  A powerful cold front will follow by Saturday, ending the heatwave with powerful thunderstorms.

A tropical air mass will be established over the region through tomorrow with fog a threat in the morning and isolated to widely scattered thunderstorms, especially in the afternoon hours.  The fog will have the potential to be locally dense with visibility below a mile.  The thunderstorms will be capable of torrential downpours, frequent vivid lightning, hail, and wind gusts up to 75 mph.  The thunderstorms will have the potential to produce flash flooding and wind damage.  Winds will be from the south at 5 to 10 mph.  Temperatures today and tomorrow will range from the lower to mid-70s over the interior and mid to upper 70s along the coast for lows and mid to upper 80s along the coast, upper 80s to lower 90s over the interior, and lower to mid-90s in the Delaware River Valley.  A heat index of 95 to 110 degrees will be a threat in the afternoon hours.

A cold front will slowly sink through the region on Saturday with widespread showers and thunderstorms in the afternoon and evening.  The thunderstorms will have the potential to reach severe levels with intense downpours, frequent lightning, large hail, wind gusts over 65 mph, and isolated tornadoes.  Winds will veer from the south to the northwest at 5 to 15 mph.  Temperatures on Saturday will range from the upper 60s to lower 70s over the interior and lower to mid-70s along the coast for lows and mid-70s to lower 80s over the interior and mid-80s to lower 90s along the coast and in the Delaware River Valley.

The cold front will stall to the south of the region on Sunday with scattered clouds and isolated showers.  Temperatures will range from the mid-50s to lower 60s over the interior and mid-60s to lower 70s along the coast for lows and upper 70s to lower 80s over the interior and lower to mid-80s along the coast and Delaware River Valley for highs.

The cold front will stall over the region Monday through Wednesday with scattered clouds and isolated showers.  Temperatures on Monday will range from the lower to mid-60s over the interior and upper 60s to lower 70s along the coast for lows and upper 70s to mid-80s for highs.  Temperatures on Tuesday and Wednesday will range from the mid-60s to lower 70s for lows and mid-70s to lower 80s for highs.

The remnants of Fred and a warm front will produce widespread rainfall on Thursday.  Temperatures will range from the upper 60s to lower 70s for lows and upper 70s to mid-80s for highs.