Boston is facing a heatwave with temperatures potentially breaking records, reaching the 90s today and near 97°F tomorrow.

As another bout of sweltering heat is set to hit Massachusetts, the MBTA is alerting riders that the extreme heat could cause delays on the commuter rail on Friday.

On a southwest wind, temps snuck up to around 90 yesterday, and today, we’ll head into the mid 90s. The record for the date

The past few days have featured near or slightly cooler than average temperatures. By Thursday, though, the sea breeze will hold off and temperatures are expected rise into the low 90s.

Cities are seeking low-cost ways to ease the heat island effect. Researchers found benefits and trade-offs in two popular options, but they vary by city and even neighborhood.

The blast of heat prompted advisories across much of Massachusetts, Rhode Island, Connecticut, and in Southern New Hampshire and Maine.

The heat index, or how it feels with humidity factored in, will rise into the triple digits for millions as the hot dome of high pressure engulfs the central and eastern states.