Forecast discussion: A low pressure system centered over the middle of the Great Lakes is creating the raw, damp, and now rainy conditions over Boston. This is not how many kids off from school this week wanted their vacation to start. According to Logan Airport we are just seeing the rain gauge accumulate the first raindrops, as of 3 p.m. Despite the rainfall, the Boston Marathon went on without a hitch, and the Red Sox did get their game in, despite playing only 7 innings.
We could see more rainfall into this evening, with the risk of some isolated thunderstorms and patchy fog. Due to the heavy rainfall and high tide expected tonight, the south coast is under a Coastal Flood Advisory from midnight to 4 a.m. During the overnight, we could see up to an inch and a half of rainfall before the precipitation ends Tuesday afternoon.
A second low will form over the Mid-Atlantic tonight, and push a warm front through Southern New England tomorrow. Temperatures will be about 15 degrees warmer by the afternoon, after the rainfall ends by mid-morning. Partly sunny skies by lunchtime will help raise the temperatures, despite the stronger winds expected by the early afternoon.
Unfortunately, this main low will take all week to move off to the east. So, many weak disturbances behind the low’s center will pass into New England. The first disturbance will come through Wednesday afternoon, and bring the risk of scattered showers into early Thursday morning. High pressure ridging to the south of the system will bring us some dry weather, along with partly cloudy skies, by Thursday night.
The end of the week looks great, but cooler air from an upper level low over the border of Canada and the state of New York will remain over us. This will make temperatures below normal for this time of the year. We will keep dry weather through Sunday, but a weak cold front will bring increasing clouds by early Sunday afternoon and isolated showers by the early evening. Another weak disturbance may bring isolated showers by the middle of the evening commute next Monday.
72 hour forecast:
Tonight: Widespread showers and isolated thunderstorms expected this evening, along with patchy fog. We will see a low of 49.
Tuesday: Showers and possible thunderstorms end by 11 a.m. with partly sunny skies by 2 p.m. We will see a high of 63 with west-southwest winds of 14-17 mph by 2 p.m.
Tuesday night: Mostly cloudy skies with a low of 45. Winds will come from the west-southwest at 8-11 mph.
Wednesday: Overcast skies with showers arriving by 2 p.m. We will see a high of 61.
Wednesday night: Showers last until 1 a.m. with a low of 44.
Thursday: Partly sunny and cool with a high of 53.
Thursday night: Partly cloudy with a low of 41.
Friday: Mostly sunny. Highs 51-54, lows 38-41.
Saturday: Mostly sunny. Highs 53-56, lows 41-44.
Sunday: Partly to mostly sunny with possible showers before 7 p.m. Highs 54-57, lows 40-43.
Monday: Partly sunny with isolated showers possible after 5 p.m. Highs 54-57, lows 43-46.