“A heat advisory may be needed during some of those periods”, according to a hazardous weather outlook issued by the NWS.
“The combination of heat and humidity will lead to heat indices above 95-100 degrees”, forecasters said.
There may be scattered clouds this afternoon, but abundant sunshine will effectively add another 5 to 15-degrees to the heat indices, making conditions extremely unsafe. While many towns will remain dry, where storms do pop up, rain could be heavy and accompanied by frequent lightning.
Storms are possible in the afternoon and evening hours, staying mainly west of I-81, said Storm Team 4 meteorologist Amelia Draper. There is a chance of showers and thunderstorms before noon and then again during the late afternoon.
Philadelphia, which hit 92 degrees on Sunday with a heat index of 105, similarly sounded the alarm to its residents and visitors about the risky heat.
Highs should run 87-92 with heat indices 97-105.
It looks like we are going to stay in this pattern of seeing scattered afternoon and early evening shower and thunderstorms for Friday through the weekend as well. Some of the storms may be strong with torrential rains likely.
We will have quite the heat wave! The library will not be open Wednesday, the Fourth of July. As a result, temperatures are expected to drop from the mid-90s to the low-70s. This week the upper-level ridge that would normally keep storm chances limited will weaken just enough to allow a disturbance in the Gulf to bring in higher storm chances.
Health officials also advise residents to check on those more at risk from high temperatures – infants and young children, people aged 65 or older, people with chronic medical conditions.
Use a buddy system when working in excessive heat. Boston got 3 straight days on Friday, Saturday & Sunday to make it an official heat wave but that was broken Monday by a high of only 83 at Logan.