New York City Mayor Zohran Mamdani ordered a citywide emergency response Thursday as severe heat and storm advisories were issued across the East Coast.
The emergency response comes as all five boroughs of New York City entered a heat advisory lasting through 8pm Friday. Similar heat alerts stretch across parts of Connecticut, New Jersey, Pennsylvania, Delaware, Maryland, Massachusetts, New Hampshire, and Washington DC.
The National Weather Service warned that heat index values could reach around 100°F in New York City, 103°F across parts of Pennsylvania, New Jersey, and Delaware, and more than 105°F in southern Connecticut. Overnight temperatures are expected to remain in the low 70s, offering little relief before oppressive heat returns Friday.
Forecasters warned that the extreme heat will coincide with severe thunderstorms capable of unleashing torrential rain, powerful winds, and frequent lightning across the Northeast and Mid-Atlantic. The storms could trigger localized flash flooding, topple trees, and bring down power lines through Friday.
New Yorkers living in basement apartments received the most urgent warning and were instructed to identify somewhere safer to shelter before floodwaters begin rising.
New York City officials urged residents to remain indoors during severe weather and to avoid flooded roads. Anyone trapped or facing immediate danger should call 911, while downed trees, clogged catch basins, and other non-emergency hazards can be reported to 311.
"City government is mobilizing every resource we have - from clearing catch basins and preparing emergency crews to sending COOL vans to check on older adults," Mamdani said. "Protecting New Yorkers means showing up before the storm, not just after it."
Hundreds of cooling centers will open across the five boroughs Thursday and Friday, including accessible and pet-friendly facilities. Locations can be found online or by calling 311.
The dangerous conditions stretch beyond the city into New York State, where eastern Ulster and western Dutchess counties could experience heat index values of up to 98°F through Friday evening.
Regional Heat and Storm Conditions
Nearly all of Connecticut is under a heat advisory, with only northern Litchfield County excluded. Heat index values could climb above 105°F in the hardest-hit areas of southern Connecticut, while Hartford could feel as hot as 102°F and New Haven could reach 103°F. Actual temperatures are forecast to rise into the upper 80s and low 90s, with oppressive humidity making conditions feel significantly hotter.
Scattered thunderstorms are expected across Connecticut on Thursday afternoon and evening, particularly in western and northwestern areas, creating a risk of localized flooding in communities recently hit by downpours. Friday will bring another round of punishing heat and a 50 to 60 percent chance of thunderstorms in parts of the state.
Much of New Jersey is also under a heat advisory through 8pm Saturday, with heat index values potentially reaching 103°F in communities including Trenton, Camden, Cherry Hill, New Brunswick, Glassboro, Freehold, Somerville, and Mount Holly. Northeastern counties including Passaic, Bergen, Essex, and Union face thunderstorms Friday that could produce powerful winds, torrential rain, and flash flooding.
Farther south, a heat advisory remaining in effect until 8pm Saturday covers a heavily populated region encompassing Philadelphia and parts of Pennsylvania, New Jersey, and Delaware, potentially exposing residents to several consecutive days of dangerous heat with heat index values up to 103°F. Communities covered include Philadelphia, Trenton, Camden, Cherry Hill, Wilmington, New Brunswick, Glassboro, Doylestown, and West Chester. Advisories were also in effect across the Baltimore and Washington DC region as a frontal boundary moving through the eastern United States fuels scattered showers and downpours.
Heat Illness Risks and Safety Guidelines
The National Weather Service, a federal agency responsible for weather forecasting and hazard warnings across the United States, issues heat advisories when dangerous heat and humidity combinations threaten public safety. Municipal governments routinely activate emergency plans to coordinate cooling centers, emergency crews, and public outreach during extreme weather events.
Extreme heat and humidity prevent the body from cooling itself efficiently, increasing the risk of heat exhaustion and potentially fatal heat stroke. Symptoms of heat exhaustion include dizziness, weakness, nausea, headache, and heavy sweating.
Heat stroke can cause confusion, loss of consciousness, and dangerously high body temperatures, requiring immediate medical attention. Older adults, young children, outdoor workers, and people with chronic health problems face the greatest danger.
Authorities urge residents across affected states to drink plenty of water, remain in air-conditioned spaces, postpone strenuous outdoor activity, and never leave children or pets inside parked vehicles.
