Thunderstorm Forecast Prompts NWS 'Hazardous Weather Outlook' for Main Line

Tuesday's National Weather Service forecast includes a good chance of afternoon and evening showers and thunderstorms, strong enough to warrant a Hazardous Weather Outlook.

"An approaching frontal boundary will present the dual threat of heavy rain and strong to possibly locally severe thunderstorms as it approaches and moves through on Tuesday," according to the NWS alert. "While the heavy rain potential exists throughout the forecast area, the greater threat for stronger thunderstorms should be in the southern and western part of the forecast area."

The alert, which the agency's Mount Holly office issued Monday afternoon, applies to most of Maryland, Delaware, Pennsylvania and New Jersey.

During the day, in the morning especially, the forecast is for some sun, with a high of 88. There's a 50 percent chance of rain, a quarter inch to half inch, after 2 p.m.

At night, mostly before 11 p.m., there's a 70 percent chance of another quarter- to half inch. The overnight low is expected to be around 68.