Forecast discussion: After a cold front came through Wednesday night, leaving some areas with scattered showers and isolated periods of rain, an upper level low helped create isolated showers over southern Plymouth and Bristol Counties. As we move into this evening, any precipitation will move off the Cape and Islands, and skies will begin to become partly cloudy during the overnight.
As we head into the weekend, Boston will see mostly sunny skies, low humidity, and warmer temperatures. We only reached a high of 76 degrees on Thursday, before easterly winds helped lower the temperature to 69 degrees by the early afternoon. This time, the July sunshine and shift to southeast winds will help us reach the lower 80’s. The high will slowly move out of the Ohio River Valley and towards New England. Our winds will turn back to the southwest by the late afternoon.
As we head into Saturday, we will begin to feel the difference in the air. Thanks to the southwest winds, the humidity will be increasing, while our temperatures remain in the lower 80’s. As we head into Saturday night, a low pressure system over eastern Montana will bring increasing clouds and the threat of some showers by the evening. We will see a greater chance at showers and isolated thunderstorms on Sunday, as the cold front slowly moves closer to the area.
The cold front will pass through on early Monday morning. However, there will be a second low along the frontal boundary. So, there will be about a three to four period in the morning when precipitation ends, before the second low brings another round of scattered showers and thunderstorms. The cold front will finally move offshore by early Tuesday morning, with partly sunny skies for the rest of the day.
A strong high pressure system will bring mostly sunny skies for Wednesday, but the models do show a weak cold front moving towards New England late Wednesday night. There is a chance for some isolated showers by the evening commute next Thursday, with a greater chance for some showers into next Friday. Temperatures during the extended period will remain below normal for the end of July. This is due to an upper level low staying near the eastern U.S. This will keep north winds over the area, allowing for cooler air to stay over New England.
72 hour forecast:
Tonight: Skies becoming partly cloudy and cooler with a low of 61.
Friday: Mostly sunny with lower humidity and warmer. We will see a high near 81 with winds shifting to the south-southeast at 9-12 mph by the late afternoon.
Friday night: Partly cloudy with a low of 64. Winds will come from the southwest at 8-11 mph.
Saturday: Mostly sunny in the morning, with increasing clouds and humidity by the mid-afternoon. We will see with a high of 83.
Saturday night: Mostly cloudy with scattered showers possible by 9 p.m. We will see a low of 69.
Sunday: Cloudy with scattered showers and thunderstorms with a high of 81.
Sunday night: Scattered showers and thunderstorms. We will have a low of 71.
Monday: Cloudy with scattered showers/thunderstorms ending for a brief period of time in the early morning. Scattered showers and thunderstorms return by mid-morning. Highs 80-83, lows 66-69.
Tuesday: Showers end by 5 a.m. with partly sunny skies by mid-morning. Highs 77-80, lows 61-64.
Wednesday: Mostly sunny. Highs 78-81, lows 61-64.
Thursday: Partly sunny with possible showers by the evening commute. Highs 78-81, lows 65-68.