With a tropical air mass in place and plenty of weak troughs on the move, thunderstorms remain a constant threat will the heat and humidity combine to produce a heat index over 100 degrees.

A tropical air mass will be established over the region today through Friday 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 will rise into the lower to mid-80s along the coast, upper 80s to lower 90s over the interior, and lower to mid-90s in the Delaware River Valley for highs.  Temperatures tomorrow and Friday 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 mid to upper 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.  The thunderstorms will have the potential to reach severe levels.  Temperatures on Saturday will range from the lower to mid-70s over the interior and mid to upper 70s along the coast for lows and mid-80s to lower 90s for highs.

The cold front will exit on Sunday with lingering showers in the morning and clearing skies in the afternoon.  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.

High pressure will be in control Monday through Wednesday with clear skies to scattered cloud cover along with lower humidity.  Temperatures on Monday will range from the upper 50s to lower 60s over the interior and mid to upper 60s along the coast for lows and upper 70s to lower 80s along the coast and lower to mid-80s away from the coast for highs.  Temperatures on Tuesday will range from the mid to upper 60s for lows and upper 70s to lower 80s over the interior and lower to mid-80s along the coast for highs.  Temperatures on Wednesday will range from the mid to upper 60s over the interior and upper 60s to lower 70s along the coast for lows and lower to mid-80s for highs.