Paterson is under a heat advisory that takes effect Monday at 11 a.m. and remains in place through Wednesday at 8 p.m., as heat-index values climb into the upper 90s and low 100s, according to the National Weather Service.

Monday will be sunny, with a high near 95 and heat index values as high as 99. Tuesday’s high near 98 is expected to feel like 104 in the afternoon. Wednesday will be mostly sunny, with a high near 97 before a 50 percent chance of showers and thunderstorms after 8 p.m.

Late-week highs ease to around 85 on Thursday, with showers likely and possibly a thunderstorm after 2 p.m. Friday will be partly sunny, with a high near 79 and a 30 percent chance of showers overnight. The weekend brings sunnier skies with a high near 81 on Saturday and 85 on Sunday, each day carrying a 30 to 40 percent chance of showers and thunderstorms.

A heat advisory is issued when heat and humidity combine to produce a heat index of 95 to 99 degrees for at least two consecutive days or 100 to 104 degrees at any time. Residents should stay in air-conditioned spaces, drink plenty of water and check on vulnerable friends and neighbors.

Outdoor workers are advised to take frequent breaks in the shade or in air-conditioned environments. Heat stroke is an emergency: anyone showing signs such as confusion, rapid pulse or loss of consciousness should be moved to a cool location and 911 should be called immediately.