Despite morning clouds and rainfall. warmer and more unstable air will push into the region through early this afternoon ahead of an advancing cold front. This will set the stage for a developing severe weather event. Thunderstorms have developed across upstate New York as of 12pm. These storms are expected to intensify and expand in coverage as they move east through the afternoon. Storms are expected to move into western New Hampshire after 2pm. reaching western Maine after 4pm. The severe weather threat should come to an end after 8pm. Storms will have the potential to produce damaging winds. large hail and isolated tornadoes. Torrential rainfall with localized flooding will also be possible. Please be alert to changing weather conditions and have a way to receive warnings from the National Weather Service.

* WHAT. Large breaking waves of 4 to 9 feet expected in the surf zone. * WHERE. Ocean exposed beaches along the south coast, Cape and Islands. * WHEN. From noon today to 7 PM EDT Monday. * IMPACTS. Dangerous swimming and surfing conditions and localized beach erosion.

* WHAT. Heat index values up to 102. * WHERE. In Connecticut, Hartford CT, Tolland CT, and Windham CT Counties. In Massachusetts, Eastern Hampden MA and Eastern Hampshire MA Counties. * WHEN. Until 7 PM EDT this evening. * IMPACTS. Hot temperatures and high humidity may cause heat illnesses.

* WHAT. South winds 10 to 20 kt with gusts up to 25 kt and waves 1 to 2 feet expected. * WHERE. Boston Harbor. * WHEN. From noon to 8 PM EDT Sunday. * IMPACTS. Conditions will be hazardous to small craft.

* WHAT. Southwest winds 10 to 20 kt with gusts up to 25 kt and waves 3 to 5 feet expected. * WHERE. Narragansett Bay. * WHEN. From 10 AM Sunday to 9 AM EDT Monday. * IMPACTS. Conditions will be hazardous to small craft.

* WHAT. Heat index values up to 94. * WHERE. Northern Middlesex, Northern New London, Southern Middlesex, and Southern New Haven Counties. * WHEN. Until 8 PM EDT this evening. * IMPACTS. Hot temperatures and high humidity may cause heat illnesses.

THE NATIONAL WEATHER SERVICE HAS ISSUED TORNADO WATCH 448 IN EFFECT UNTIL 8 PM EDT THIS EVENING FOR THE FOLLOWING AREAS IN MASSACHUSETTS THIS WATCH INCLUDES 6 COUNTIES IN CENTRAL MASSACHUSETTS WORCESTER IN EASTERN MASSACHUSETTS MIDDLESEX IN NORTHEASTERN MASSACHUSETTS ESSEX IN WESTERN MASSACHUSETTS FRANKLIN HAMPDEN HAMPSHIRE THIS INCLUDES THE CITIES OF FITCHBURG, FRAMINGHAM, GLOUCESTER, GREENFIELD, LAWRENCE, LOWELL, NORTHAMPTON, SPRINGFIELD, AND WORCESTER.