* WHAT...Heat index values up to 100.

* WHERE...All five boroughs of New York City.

* WHEN...Until 8 PM EDT Saturday.

* IMPACTS...Heat and high humidity may cause heat related illnesses.

* ADDITIONAL DETAILS...The advisory may need to be extended as heat and humidity persist.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

New York City residents should call 3 1 1 to identify cooling center locations and obtain 'Beat the Heat' safety tips.

A Heat Advisory is issued when the combination of heat and humidity is expected to make it feel like it is 95 to 99 degrees for two or more consecutive days, or 100 to 104 degrees for any length of time.

Seniors and those with chronic health problems or mental health conditions are at an increased risk. Homes without air conditioning can be much hotter than outdoor temperatures.

Use air conditioning to stay cool at home or go to a place that has air conditioning. If you don't have home air conditioning, continue to seek out cool spaces each day as long as it remains hot, and for a few days after if your home is still hot. Check on vulnerable friends, family members and neighbors.

To reduce risk during outdoor work, the Occupational Safety and Health Administration recommends scheduling frequent rest breaks in shaded or air conditioned environments. Anyone overcome by heat should be moved to a cool and shaded location. Heat stroke is an emergency! In cases of heat stroke call 9 1 1. close