Will There be a Storm for New England Next Week? Breaking Down the Setup

The trough axis we've been under will begin to shift eastward while high pressure builds in from the west this weekend. Overall, broad troughing is expected to persist over the region while surface high pressure keeps the region dry (something that was in question earlier in the week). This will allow for partly to mostly cloudy skies and continually dropping temperatures, with widespread highs in the mid 40s north to mid 50s south.

A stubborn upper-level low will remain east of New England through early next week. This system will likely retrograde southwestward from around Nova Scotia back toward the Gulf of Maine. As this system pushes closer to New England, it will likely allow for some shower activity this weekend. On Saturday, showers will be very isolated and most likely across interior Maine. Elsewhere could see a few pin-prick showers develop, similar to Friday afternoon and evening.

The system will be closer on Sunday, so showers will likely be more numerous across northern New England during the day. Isolated showers are likely to develop Sunday morning and likely peak in coverage around mid-afternoon. The mountains could see some snow showers as the freezing level potentially drops to around 3,000 feet Sunday afternoon. Southern and central New England will see much more isolated activity with most in these areas staying completely dry.

Below: HRRR showing potential weather Sunday afternoon:

Early next week (around Monday and Tuesday), a rather weak storm system will likely pass well offshore of New England. While the Upper-level low will inject some energy into this system, a lack of phasing with the northern stream will keep this system well away from New England. Showers from this will be most likely across southeast Massachusetts, mainly from a moist low-level flow off the ocean.

Below: Euro showing the initial storm system pass well offshore early next week:

Heading toward the middle and latter part of next week, there continues to be a cloud of uncertainty over just how things will play out in regards to a potential nor'easter impacting New England. This uncertainty stems from several large-scale features that will be interacting with each other across the east. How these features interact, along with their exact position and strength, will determine how things play out. The broad setup will include a large ridge over eastern Canada and broad troughing across the eastern United States with another ridge in the west.

Below: 500mb height anomaly next Thursday showing what is described in the paragraph above:

This broad setup will allow for continued unsettled weather with an organized coastal storm developing across the southeast early next week. This system will slowly push northward along the east coast through the week, likely arriving in New England by late Wednesday or Thursday. The level of impact from this system will come down to how much it can strengthen and the level of phasing between this system and a northern stream system.

More phasing will push the storm closer to New England, bringing heavier rain and more wind while less phasing would keep the storm over the ocean, resulting in less impacts across more of New England. Complicating the forecast further is Tropical Storm (soon to be hurricane) Melissa. This storm will slowly track northeastward through the middle of next week. The overall setup will help keep Melissa well away from the east coast, but how it interacts and influences the formation of the nor'easter makes things more difficult for guidance to figure out.

Looking at the latest trends, this may not be a high-impact event for New England. Current rainfall forecasts show a widespread 1-2 inches of rain. This system may be long and drawn out, so this 1-2 inches would fall over a period of greater than 24 hours, meaning rainfall may not be too heavy. This rainfall is still needed after a long dry stretch to close out summer and start fall.

Below: Current 7 day rainfall outlook:

The pressure gradient between the high to the north and coastal low will support windy conditions, but nothing is popping out as being too significant at this time. To top it off, astronomical high tides are on the lower end, which will help to greatly reduce the coastal flood threat. Nothing is set in stone, and the spread between the least impactful and most impactful solutions has actually grown over the past couple days, meaning things have gotten less confident in terms of impacts. The overall setup is quite chaotic and things could trend toward a more or even less impactful storm.

As for timing, the system will likely arrive later on Wednesday and possibly peaking on Thursday. When the system exits is another major point of contention. With a blocking high in place, the system will be slow to exit. Showers will likely persist into Halloween; whether these are just residual showers or a more impactful rain (in terms of holiday plans) remains to be seen.