We’ve got a rather complicated forecast coming up as we officially end astronomical summer and begin fall with the autumnal equinox at 2:50am Saturday.
High pressure to our north will keep us dry and seasonably cool into Friday. However, high clouds will begin to stream northward from what is currently being called “Potential Tropical Cyclone 16”, but will likely be named Ophelia soon. Whether it is tropical or subtropical doesn’t have much impact on the forecast. Future Ophelia will likely strengthen a bit before moving into eastern North Carolina early Saturday.
As our high pressure system moves off to the east, southerly flow will send the rain up the East Coast. This is where things get tricky, because another high pressure area will also be trying to build in from the northwest. We’ve seen this setup many times before, and what usually happens is that the high wins out and keeps most of the rain (or snow in the winter) off to our south. However, anytime there’s been a chance for rain this summer, we’ve ended up with a lot of rain. So, taking both of those ideas into account, here’s what we think will happen:
The rain will move up the coast on Friday and Friday night, but will have a tough time moving in early Saturday with plenty of dry air in place. Eventually, the rain will win out, overspreading the region during the afternoon. How far north it gets is still a big question, and it wouldn’t be a surprise to us if the rain never made it across the MA/NH border. Some of the rain may be heavy during the late afternoon and evening, especially south of the Mass Pike. The rain may taper off for a while Saturday night and early Sunday as the second high tries to build in, and the low to the south moves up into the Mid-Atlantic states. A second batch of showers is possible later Sunday and Sunday night as the low starts to turn more toward the northeast, eventually passing out to sea south of New England on Monday, with some additional showers possible.
Thursday night: Clear skies, though some high clouds will start to move in. Low 47-54.
Friday: Sunshine filtered through high clouds in the morning, clouds thicken up in the afternoon. High 65-72.
Friday night: Mostly cloudy. Low 49-56.
Saturday: Showers developing from south to north during the late morning and early afternoon, becoming a steady and potentially heavy rain by late afternoon. High 58-65 during the morning, temperatures drop into the 50s during the afternoon.
Saturday night: Rain tapers off to showers during the evening, mostly cloudy overnight. Low 49-56.
Sunday: Plenty of clouds, some showers may redevelop during the afternoon. High 60-67.
Sunday night: Cloudy with showers likely. Low 50-57.
Monday: Mostly cloudy, more showers around, especially during the morning. High 61-68.
Storm HQ 