 Later on this evening, big storms are possible in the heat and humidity, but right now the heat is the big story. It feels thick out there. That's the best way I can describe it with dew points in the mid to upper 70s. Tony says the best chance of thunderstorms after 6 o'clock. Meantime, an excessive heat warning in effect for Baltimore City and points south until 8 tonight. Heat advisory in effect for much of the rest of the Maryland until 8.