Temperatures are forecast to hit the lower 90s Tuesday with the heat and sunshine fueling a rise in ozone pollution, prompting an air quality alert.

A "code orange" air quality alert is in effect, a hazardous level for children, the elderly and those with respiratory conditions. Sunshine-fueled chemical reactions involving fossil fuel exhaust and other particles was spawning a rise in ozone, a gas found high up in the atmosphere that is considered a pollutant closer to the ground.

Highs are forecast around 92 degrees downtown under partly cloudy skies. The daytime heating could fuel afternoon or evening thunderstorms, with about a 30 percent chance. Early morning temperatures dropped only to the upper 60s at BWI Marshall Airport.

Hotter conditions are forecast Wednesday, with highs in the mid-90s and humidity making it feel like close to 100 degrees. Storms are again possible in the afternoon and evening.

Storm chances and highs in the lower 90s are expected again Thursday, with highs dropping back to the 80s Friday and Saturday but lingering storm chances.