Just like that, meteorological summer has drawn to a close. While the end of the summer went out with a bit of a whimper when it comes to summer heat, much of this summer was dominated by stretches of intense heat and humidity. Similar to last summer, the season also featured several notable flooding events across New England as well as several rounds of severe weather.
The first big brush with heat this summer ended up being the most intense for New England. The week of June 17th to the 22nd featured a strong heat dome set up just to the southwest of New England. This pumped very hot and very humid air into the region. Rare (for New England) excessive heat warnings were issued across a large portion of New England throughout the week. In fact, this week featured the first such alerts ever issued by the National Weather Service office of Caribou, Maine.
Air temperatures combined with dew points in the mid to upper 70s sent heat index values soaring near 110° in places during the week. On June 19th, Caribou, Maine tied their all-time highest temperature on record when it reached 96°. Caribou's heat index value shot well over 100° that day.
While this intense heat would relent heading toward the end of June, it would come back for an extended period in July. Much of July featured constant heat and humidity, a far cry from last July, which struggled mightily to maintain heat. The semi-permanent Bermuda high pressure system over the Atlantic Ocean maintained its strength and was very expansive for much of the month. This kept New England in a nearly constant southwest flow for the month, pumping the heat and humidity into the region.
Manchester and Concord, New Hampshire set New all time records for longest heat waves. Concord saw 12 straight days at 90+° while Manchester saw 14. Manchester's 14 day heat wave was among the longest in New England's history. The next longest among New England's major cities is 10.
Of course, it's not just the heat, it's the humidity, as the old weather adage goes. In Boston, the maximum dew point has topped out at 70° or higher from July 4th to the 18th, 15 days in a row. The average dew point for the entire day hit 70° or higher for nine of the 15 days. These are truly tropical-like levels. These high dew points keep the overnight lows warm. The overnight low stayed above 70° for 12 of the 15 days. It did not drop below 70° in Boston at any point during the day from July 9th to the 18th.
While August did provide much more heat relief, the constant heat and humidity in June and July led to this summer ranking as among the warmest on record for many of New England's climate sites. Hartford, Caribou and St. Johnsbury saw their all-time warmest summers on record. This was driven primarily by warm overnight lows. The southern New England coast was generally cooler, with Boston and Providence seeing a more run-of-the-mill ranking when it comes to all-time warmest summers.
While prolonged heat was a change in pace from last summer, this summer was (unfortunately) similar to 2023 in regards to several rounds of intense flooding. Flash floods caused locally significant damage in parts of the region on July 10-11, July 30 and August 18. The remnants of Beryl moved through New England on the anniversary of the Great Flood of 2023, bringing another round of heavy damage to Vermont communities such as Barre, Lyndonville, Plainfield and more.
On July 30th, a cutoff low pressure system brought an unexpected deluge to Vermont's Northeast Kingdom. This storm brought upwards of 8 inches of rain in less than six hours. St. Johnsbury saw nearly a half foot of rain within three hours. On August 18th, another unexpected deluge struck New England, this time in Connecticut.
Portions of southwest Connecticut saw 10-12+" of rain within 24 hours. A 24 hour rain total of 14.83" in Oxford is currently being analyzed by the State Climate Extremes Committee to see if the total is accurate. If the total is accurate, it will be a new 24 hour rainfall record for Connecticut. The previous record was 12.77" set in 1955.
Images of flooding around New England this summer:
These storms added many communities to a growing list of towns and cities in New England to see at least six inches of rain from a single storm. In the last two years, a total of 48 different communities in the region across five states have seen this impressive total.
Along with the flooding events, New England saw the usual rounds of severe thunderstorms. On the heels of June's heat dome, a potent setup for rotating thunderstorms set up for New England. A large portion of New England was placed in a 10% risk for tornadoes on June 23rd. For context, this was only the third time since 2010 that the Gray, Maine forecast area (which covers all of New Hampshire and the western half of Maine) has seen a tornado outlook that high.
That day saw six tornado warnings issued, with three occurring simultaneously. Fortunately, only one tornado was confirmed during this event (an EF1 in Dublin, New Hampshire). Connecticut was hit particularly hard by severe weather this season. Many severe events ended up being centered over the state. This includes a very intense line of storms that moved through southern New England on June 26th. This line brought wind gusts near 80mph to Connecticut and resembled a mini-derecho.
Meteorological summer (June to August) saw a total of five tornadoes touch down in New England. The second half of summer was much quieter than the first half in this regard with the last tornado touchdown in New England occurring on July 16th. As we go through a seasonal transition yet again, here's a look at key fall dates:
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