New England has been experiencing an unusually dry fall. While the entire region is in a rainfall deficit for the season, southern New England has been bone dry in some places. Hartford has so far experienced their driest two month stretch on record in September and October 2024. The city has seen 1.1 inches of rain since September 1st. This is currently beating the old two month record of 1.2 inches, set in December and January 1981. While there's another week left in October, a tenth of an inch may be hard to come by for the city.
Boston has seen a total of eight days with measurable rainfall since September 1st. Going back to August, the city experienced one of its longest stretches of days without measurable rainfall on record. The city went 29 days without precipitation from August 21st to September 19th.
While southern New England has seen less rain, northern New England does remain in a deficit as well. Caribou, Maine has seen 2.32 inches of rain since September 1st. This is over 4 inches below average for this time frame. Concord, New Hampshire is running 3.74 inches below average.
This dry weather has led to drought conditions beginning to expand across portions of New England. Eastern Massachusetts, southeast New Hampshire and eastern Maine are currently under moderate drought conditions. Other areas remain in the abnormally dry category. The timing of this dry weather in the fall has helped keep these conditions in check with the weaker sun angle versus if this dry weather had set up during the heat of summer. A very wet August has so far prevented drought conditions in central Connecticut.
Below: Current US drought monitor:
While this stretch of dry weather has been record breaking for areas just south of New England into the Mid-Atlantic, New England has avoided venturing into this territory. Widespread rains on October 7th-8th and October 13th-14th brought much needed rain to the area. Without those two events, all of New England would be extremely dry this season. A coastal storm brought a 6-12 inch deluge to Cape Cod in September as well.
After the mid-October rainfall for New England, the region is currently entrenched in yet another prolonged stretch of dry weather with just a couple frontal boundaries having brought a bit of shower activity since. The question now turns to when New England will get another dose of widespread rain. A frontal boundary will cross New England on Saturday, bringing a chance for a few showers in northern New England. Scattered showers may continue on Sunday. This will likely be a dry passage for southern New England.
After that, another system will pass to the north of New England early next week, pulling its warm front across the region. This may be able to trigger a round of scattered showers for the northern tier of New England, but southern areas are currently looking to largely miss out once again. These are the two best shower chances for New England. There are currently no widespread rain chances in the picture for southern New England.
Current Weather Prediction Center 7-day precipitation forecast:
New England's weather pattern so far this fall has been one of persistence. The pattern has generally been toward prolonged periods of ridging and high pressure followed by much more brief periods of troughing and low pressure passing to the north of the region. This has really limited the amount of rain chances for New England.
This pattern does look to continue into the extended forecast with a trough-in-the-west-ridge-in-the-east pattern setting up for Halloween week. This will continue to keep high pressure and dry air over New England much of the time. This will also allow for temperatures to climb back to above average levels for next week.
Below: 500mb height anomaly forecast showing the pattern described above (prolonged ridging followed by brief troughing) continuing through next week. You can also the trough-in-the-west-ridge-in-the-east pattern setting up next week:
This autumn has been so dry thanks to this pattern of persistence. The season has been dominated by expansive and strong areas of high pressure over the northeast. This has led to dry air setting up over New England and most storm systems getting deflected away. With ridging over the northeast, northern stream systems have been forced well to the north of New England, keeping their precipitation to the north as well (you can see how much rain is expected to New England's north over the next seven days on the 7-day outlook above).
For New England to get widespread rain, we really need a system from the more moisture-rich southern stream to interact with a northern stream system. This just hasn't been able to happen with the ridging that has been in place.
This high pressure has also kept the remnants of hurricanes away, something that often soaks New England in September and October. Remnants of Francine and Helene were blocked to the southeast instead of racing through the northeast. Most recently, Oscar was pushed well away from New England yesterday due to the cold front. With all of that said, the generally dry fall is looking to continue for now, especially for southern New England.
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