Summer officially ends at the Autumnal Equinox at 2:19 this afternoon, but summer-like weather will continue beyond that.
High pressure remains in control for today and part of Tuesday, keeping us dry, as has been the case for much of the summer. After a cool weekend, temperatures will start to moderate a bit today, but Tuesday will be rather warm and somewhat humid, with many locations likely topping 80. Clouds will start to move in during the day as a frontal system approaches the region. This will bring in some showers and possibly some thunderstorms late in the day and at night. As the front slows down, a wave of low pressure will ride along it on Wednesday, bringing in some additional showers along with much cooler temperatures. We do need the rain, and some models show the potential for some very beneficial amounts. However, for the most part, they have overestimated rainfall with several recent systems, plus there’s an old adage that usually holds true when talking about rainfall forecasts during a drought – “When in Drought, Leave it Out”. So, even though Wednesday will be a cool and damp day, it’s likely not going to be the widespread heavy rain that we need.
High pressure builds in for Wednesday night and early Thursday with some drier air, but it won’t last long. An upper-level low pressure system and its surface reflection over the Great Lakes will start to slowly move into southeastern Canada toward the end of the week. The models are all over the place with the timing and strength of this system, but it looks like a second period of rainfall is expected possibly starting as early as Thursday afternoon, continuing into Friday night or possibly Saturday. Temperatures on Friday could be tricky. Several models show the system sending a warm front across the region, so even though we’re expecting more showers, temperatures could get well into the 70s. Of course, if the front gets hung up south of New England, temperatures may stay stuck in the 60s. We’re leaning towards the warmer scenario for now, but it is far from a lock. The system pulls away on Saturday then high pressure builds back in with drier air for Sunday.
Monday: Partly to mostly sunny. High 68-75.
Monday night: Clear skies during the evening, becoming partly cloudy overnight. Low 54-61.
Tuesday: A mix of sun and clouds through midday, then clouds thicken up in the afternoon with some late-day showers and thunderstorms develop. High 76-83.
Tuesday night: Cloudy with showers likely. Low 58-65.
Wednesday: Cloudy and cooler with more showers. High 66-73.
Wednesday night: Mostly cloudy, showers ending in the evening. Low 54-61.
Thursday: More clouds than sun, showers may redevelop in the afternoon. High 64-71.
Thursday night: Cloudy with showers likely. Low 55-62.
Friday: Mostly cloudy with additional showers, mainly in the morning. High 70-77.
Saturday: Morning clouds and a few showers across the Cape and Islands give way to some afternoon sunshine. High 70-77.
Sunday: A mix of sun and clouds. High 68-75.
Storm HQ 