Forecast discussion: A warm front came through Southern New England on Sunday, helping to keep cloudy skies and isolated showers over Boston. The warm front is now offshore, but the increased humidity and some instability in our atmosphere may help trigger a shower during the overnight. Thunderstorms will dissipate as we continue to lose the sunlight.
The cold front associated with a low pressure system in eastern Canada will pass through sometime tomorrow. The humidity will remain, as winds stay from the southwest. We will see isolated showers and thunderstorms through the day, and it will be slightly warmer than Sunday. We are awaiting an upper level ridge to move over the eastern U.S. by Monday night. This will help bring even warmer air further north, and provide us with the first real chance for a heat wave in eastern Massachusetts.
It all begins on Tuesday, as a weak high pressure system dries out part of the atmosphere. The humidity will remain, but sunshine is expected for the whole day. Right now, high temperatures are forecast to reach the upper 80’s. But, I would not be surprised if inland areas west of Boston reach 90. Due to the heat and humidity, a shower or thunderstorm could develop in the late afternoon or early evening.
We will see mostly sunny skies for Wednesday, and this has the best chance to be the warmest day of the week. Temperatures are expected to reach the lower 90’s. A Heat Advisory might be needed if heat indexes reach 100 degrees. The nights will not be as comfortable either without a fan or air conditioning. Low temperatures are only expected to fall into the lower 70’s.
By Thursday, we are expecting a cold front to reach New England, providing us with the risk of showers and thunderstorms by the mid-afternoon. This will break the possible heat wave by Thursday night, as some cooler and less humid air arrives. The front will move offshore by the middle of Friday morning, and we will return to mostly sunny skies. A quick disturbance passes through early Sunday morning, giving us the risk for some precipitation. Otherwise, high pressure returns us back to sunshine. It will not be cool in the extended period, but we will not reach 90 degrees in the daytime, either.
72 hour forecast:
Tonight: Scattered showers with thunderstorms dissipating by 10 p.m. It will be quite humid with a low of 71.
Monday: Overcast with scattered showers and an isolated thunderstorm. It will remain quite humid. We will see a high of 83 with southwest winds of 8-11 mph.
Fenway Park Forecast (7:10 p.m. vs. White Sox): Cloudy, passing shower or thunderstorm, 76.
Monday night: Overcast with isolated showers until 5 a.m. Patchy fog is expected. We will see a low of 70 with west-southwest winds of 7-10 mph. Partial clearing is expected after sunrise.
Tuesday: Skies slowly become mostly sunny, and it remains hot and humid. We will see a high of 87. There is the slight chance for an afternoon shower/thunderstorm.
Tuesday night: Partly cloudy and still humid with a low of 72.
Wednesday: Mostly sunny, hot, and humid with a high of 91.
Wednesday night: Partly cloudy with increasing clouds towards sunrise. It will remain oppressive with a low of only 73.
Thursday: Mostly cloudy with possible mid-afternoon showers/thunderstorms. Highs 90-93, lows 72-75.
Friday: Isolated showers/thunderstorms until 9 a.m. with mostly sunny skies. Highs 84-87, lows 67-70.
Saturday: Mostly sunny through the day, with increasing clouds by the early evening. Highs 86-89, lows 67-70.
Sunday: Overcast with scattered showers/thunderstorms between 3 a.m. and 8 a.m. Partly sunny skies expected for the rest of the daytime hours. Highs 84-87, lows 65-68.