We’ve seen some pretty wild temperature swings over the last week.
High pressure was sitting directly overhead this past weekend, yielding beautiful daytime weather but also setting us up with some prime radiational cooling conditions at night. After a mild day Friday that reached 80° F, the clear skies, fairly dry air, and calm winds of Friday night led to an impressive temperature drop. Under nearly perfect nighttime conditions, Friday’s daytime heat was able to radiate away with ease, and temperatures plummeted during the second half of the night. Early risers on Saturday morning saw temperatures in the 40s (!) around a good chunk of the Cape, and if you’d left the windows open, it was flat-out cold. Here on the Outer Cape, Provincetown Airport officially clocked in with a crisp 45° F.
But that layer of cool air was very, very shallow, and as soon as the wind kicked in and the Sun started to rise, the cold was mixed out, and temperatures jumped back into the 60s. By mid-morning, readings were in the 70s, and by Saturday afternoon temperatures had climbed all the way back to the upper 70s — many spots witnessed a 20-to-30-degree temperature rise. Blankets to A/C in a matter of hours: it was a remarkable turnaround, especially for this time of year.
That big temperature jump was a signal of incoming heat and humidity. Sunday had temperatures in the lower 80s, and by Monday we were flirting with 90° F — with the heat and humidity set to persist through the rest of the week.
Forecast-wise, there’s not a whole lot to talk about locally. A frontal zone cutting through the region on Thursday and Friday will knock back the heat and humidity a bit and may generate a few showers and thunderstorms around the area as it does so. Behind the front, warm but less humid air is likely to be in place for the upcoming weekend. Temperatures look to be near to above average overall for the foreseeable future with no major precipitation on the horizon.
That said, last week it was evident that the tropical Atlantic would start to come alive in the days ahead and that’ll be the main meteorological focus for the time being. The overall atmospheric environment across the tropics will be favorable for cyclone development as we move through the second half of August, and several tropical waves traversing the Atlantic will need to be monitored for development. There has been — and remains — a fairly strong signal in operational and ensemble forecast guidance for a tropical storm or hurricane to be nearing the Eastern seaboard between the 20th and 24th of the month. Should that materialize, all temperature and precipitation forecast bets are off the table.
