A tornado warning is in effect for Philadelphia and parts of southeastern Pennsylvania, including Montgomery, Chester, Delaware and Bucks Counties until 5:45 p.m, the National Weather Service says.Tuesday's weather forecast brings two distinct risks to the Philadelphia region — we've issued a NEXT Weather Alert for excessive heat during the day and chances of storms at night.

Rounds of violent storms that arrived during the peak afternoon commuting period Tuesday set off four tornado warnings, took down trees, and flooded roadways across the region — with a sequel possible later in the week.