Forecast discussion: After several weeks of heat and humidity, Boston felt more like late spring on Thursday, as temperatures only reached the middle 60’s in overcast skies. We also had precipitation during the afternoon, as Logan Airport received about a quarter of an inch of rain. We will see the potential for more precipitation this evening into Friday afternoon.
The precipitation is due to a frontal boundary that moved offshore Wednesday afternoon. However, the boundary stalled, and is now actually turning back towards the north and west. A low pressure center formed off the Carolina coastline, and is helping to create some heavier precipitation for this evening. In lieu of some significant precipitation, the National Weather Service issued a Flash Flood Watch for most of eastern Massachusetts, including the Cape and Islands, from 10 p.m. EDT until noon on Friday. The front will slowly push back towards the Atlantic during the afternoon, and we should see partial sunshine before sunset.
As we move into the weekend, a high pressure system over eastern Canada will give us mostly sunny skies and warmer temperatures on Saturday. However, we will see some high to middle level clouds work over the region by Saturday night. A cold front in the Central Plains right now will bring more showers and thunderstorms by the early afternoon on Sunday. The front will remain inland through Monday afternoon, before drier air moves over New England Monday night.
We will see sunshine on Tuesday, with partial sunshine on Wednesday. A slow moving cold front will help create some showers by Wednesday evening. Right now, the computer models suggest a weak area of low pressure will move up into the front by Thursday, giving us more showers and periods of rain.
Meanwhile, Tropical Storm Dorian is located at 16.5N 37.8W, or about 1670 miles east of the northern Leeward Islands. Maximum sustained winds are at 60 mph with gusts of 75 mph, and is moving west-northwest at 18 mph. At this time, Dorian will continue on a west-northwest track over the next 5 days, while slowly intensifying as it moves into warmer waters. Dorian will become a strong Tropical Storm by Monday afternoon, with the chance of becoming a hurricane by early Tuesday morning. The system would be north of the Dominican Republic within 5 days.
72 hour forecast:
Tonight: Overcast with showers, periods of rain at times, and isolated thunderstorms with a low of 60. Patchy fog is expected by 11 p.m.
Friday: Showers and isolated thunderstorms ending by the late afternoon with partly sunny skies for the rest of the day. We will see a high of 74 with north-northwest winds of 12-15 mph.
Friday night: Partly to mostly cloudy with a low of 64. Winds will come from the west-southwest at 4-7 mph.
Saturday: Mostly sunny through the mid-afternoon with increasing clouds into the evening hours. We will see a high of 85.
Saturday night: Mostly cloudy with a low of 69.
Sunday: Cloudy with showers/thunderstorms by the early afternoon and a high of 82.
Sunday night: Showers/thunderstorms with a low of 70.
Monday: Lingering showers into the afternoon before partial clearing during the evening hours. Highs 82-85, lows 66-69.
Tuesday: Partly to mostly sunny. Highs 83-86, lows 65-68.
Wednesday: Partly sunny with some showers arriving in the evening. Highs 83-86, lows 68-71.
Thursday: Cloudy with showers and possible periods of rain. Highs 84-87, lows 69-72.