* WHAT. Heat index values up to 99. * WHERE. Western Essex MA County. * WHEN. Until 8 PM EDT Tuesday. * IMPACTS. Hot temperatures and high humidity may cause heat illnesses.

* WHAT. Heat index values up to 99. * WHERE. Portions of northern Connecticut, central, eastern, southeastern, and western Massachusetts, and northern Rhode Island. * WHEN. Until 8 PM EDT Tuesday. * IMPACTS. Hot temperatures and high humidity may cause heat illnesses.

The Connecticut Department of Environmental Protection has issued an Air Quality Action Day for Ground Level Ozone, from 11 AM to 11 PM EDT Tuesday. An Air Quality Action day means that Ground Level Ozone concentrations within the region may approach or exceed unhealthy standards. For additional information, please visit the Connecticut Department of Energy and Environmental Protection website at: https://portal.ct.gov/deep

The Massachusetts Department of Environmental Protection has issued an Air Quality Alert for Ground Level Ozone, from 11 AM to 11 PM EDT Tuesday. An Air Quality Alert means that Ground Level Ozone concentrations within the region may approach or exceed levels that are Unhealthy for Sensitive Groups. Air is unhealthy for sensitive children and adults, such as those with asthma, lung or heart disease, and older adults. Sensitive children and adults should limit prolonged outdoor activity. For additional information, please visit the Massachusetts Department of Environmental Protection website at: https://mass.gov/orgs/massachusetts-department-of-environmental- protection

* WHAT. Heat index values up to 100. * WHERE. In Connecticut, Northern Fairfield, Northern Middlesex, Northern New Haven, Northern New London, Southern Fairfield, and Southern New Haven Counties. In New York, Northern Nassau and Northwest Suffolk Counties. * WHEN. Until 8 PM EDT Tuesday. * IMPACTS. Hot temperatures and high humidity may cause heat illnesses. * ADDITIONAL DETAILS. An extension of this advisory into Wednesday may be needed.

The Connecticut Department of Environmental Protection has issued an Air Quality Action Day for Ground Level Ozone, from 11 AM to 11 PM EDT Tuesday. An Air Quality Action day means that Ground Level Ozone concentrations within the region may approach or exceed unhealthy standards. For additional information, please visit the Connecticut Department of Energy and Environmental Protection website at: https://portal.ct.gov/deep

* WHAT. Heat index values up to 97 expected. * WHERE. Strafford, Eastern Hillsborough, and Interior Rockingham Counties. * WHEN. From noon to 8 PM EDT Tuesday. * IMPACTS. Hot temperatures and high humidity may cause heat illnesses.

* WHAT. Visibility one quarter mile or less in dense fog. * WHERE. In Massachusetts, Barnstable MA, Dukes MA, and Nantucket MA Counties. In Rhode Island, Block Island RI. * WHEN. Until 11 AM EDT Tuesday. * IMPACTS. Low visibility could make driving conditions hazardous.

* WHAT. Visibility one quarter mile or less in dense fog. * WHERE. In Massachusetts, Southern Bristol MA and Southern Plymouth MA Counties. In Rhode Island, Newport RI and Washington RI Counties. * WHEN. From 11 PM this evening to 11 AM EDT Tuesday. * IMPACTS. Low visibility could make driving conditions hazardous.

* WHAT. Heat index values between 95 and 99. * WHERE. Portions of northern Connecticut, central, eastern, northeastern, southeastern, and western Massachusetts, and northern Rhode Island. * WHEN. Until 8 PM EDT Tuesday. * IMPACTS. Hot temperatures and high humidity may cause heat illnesses.