Forecast discussion: After some showers and light rain early Saturday morning, we had sunshine in Boston for most of Saturday. However, it remained humid, and this weather pattern will remain over Southern New England for the next few days.
A strong upper level trough over the Ohio River Valley is helping to keep cooler temperatures over the region, but it is also keeping southwest winds. The southwest winds come from the Gulf of Mexico, which keeps feeding moisture up into the Northeast U.S. This is why we have had high humidity for the last week. Unfortunately, this weather pattern will not change. So, any sunshine during the daytime on Sunday will help increase the risk of showers and thunderstorms. Some precipitation may be heavy at times, which could cause some street flooding in areas with poor drainage systems.
The weather pattern will change by Tuesday, as the blocking pattern in the upper levels of the atmosphere come to an end. The upper level trough will actually go backwards, or retrograde, allowing for a weak upper level ridge of high pressure to build over us. This will help bring some more sunshine into our forecast, but it will remain quite humid. Also, high temperatures will slowly creep upward, and it will feel slightly more miserable outside. Heat indexes will make it feel like the lower 90’s by the time we arrive at the Fourth of July. We will be able to exclude any shower or thunderstorm activity from the forecast by Friday.
72 hour forecast:
Tonight: Partly to mostly cloudy with a possible shower or thunderstorm. Patchy fog will develop after midnight. We will see a low of 67.
Sunday: Partly to mostly cloudy with possible showers and thunderstorms during the late afternoon with a high of 79. Winds will come from the south-southwest at 9-12 mph.
Fenway Park Forecast (1:35 p.m. vs. Toronto Blue Jays): Partly sunny, chance of shower/thunderstorms before end of game, 79.
Sunday night: Mostly cloudy with scattered showers and thunderstorms with a low of 68. Patchy fog will develop after 2 a.m. Winds will come from the southwest at 7-10 mph.
Monday: Mostly cloudy with possible showers and thunderstorms with a high of 80.
Monday night: Scattered showers and a low of 70.
Tuesday: Partly sunny with possible showers and thunderstorms in the afternoon and a high of 81.
Tuesday night: Mostly cloudy with possible showers and thunderstorms and a low of 69.
Wednesday: Partly to mostly sunny. Highs 84-87, lows 68-71.
Fourth of July: Partly sunny with possible afternoon thunderstorms. Highs 84-87, lows 68-71.
Friday: Mostly sunny. Highs 85-88, lows 68-71.
Saturday: Partly sunny. Highs 85-88, lows 69-72.