The current heat wave may last six days — which would make it the longest heat wave in Boston since 1997 — and may also bring oppressive temperatures nearing 100 degrees Thursday, the National Weather Service said.
Skies will be bright and sunny today, with high humidity levels and temperatures in the mid-90s as the region sweats its way through the third official heat wave in two months, the weather service said.
Today would be the fourth day of temperatures of 90 or more have been recorded. An official heat wave requires only three days in a row.
A heat advisory has been issued for 11 a.m. to 7 p.m. today for Southeastern Massachusetts, where the combination of 90-degree temperatures and high humidity levels will lift apparent temperatures to around 100 degrees, according to the weather service.
Coastal areas will again be graced with a sea breeze today that could moderate temperatures into the upper 80s in that area, although today’s sea breeze is not expected to push as deep inland as in previous days, according to the weather service.
Boston has a 20 percent chance of a brief shower and thunderstorm today, but any precipitation will dissipate by this evening. Tonight will see mostly dry conditions, with temperatures bottoming out in the mid-70s, according to the weather service.
An excessive heat advisory has also been issued for Southeastern Massachusetts for most of Thursday.
“It looks like we are going to see temperatures in the mid-90s for Thursday and Friday,’’ said meteorologist William Babcock. “But if the atmosphere gets a little warmer over the next couple of days, we could be up around 98 or 99.â€
Dewpoints could tick up to around 72 or 73 on Thursday, exceptionally humid, with skies remaining clear and sunny, according to the weather service.
Friday and Saturday will mimic Thursday’s excessive heat, with a greater chance of heavy showers and thunderstorms statewide. Skies will become partly cloudy Friday and Saturday, with dewpoints in the high 60s and temperatures in the lower 90s.
A cold front is likely to approach from the Great Lakes by Saturday night, and assert itself over the state by Sunday.
“By Saturday night or Sunday the front will push through, which will push the humidity south and make dewpoints drop to around 60,†Babcock said.
Starting Sunday and lasting until Tuesday dewpoints will lower substantially, wavering in the 50s and 60s, Babcock said. Temperatures will become seasonable starting Sunday, with highs in the mid-80s, although humidity and heat are likely to strike again Wednesday.
It’s possible a fourth heat wave will develop late next week, the weather service said.
Jasper can be reached at jasper.craven@globe.com or on Twitter @Jasper_Craven
