New England Weather This Week: Unsettled Under a Trough
- Tim Dennis
- Mar 24
- 4 min read
This will be an active and unsettled week as troughing remains persistent over New England. There are multiple chances for rain and snow through the week with the most impactful possibly coming this weekend.
MONDAY
A large trough of low pressure will remain to New England's northwest today. A secondary low will form this morning across the Mid-Atlantic and track northeastward, though southern New England. As this low moves northward, it will allow precipitation to transition from being more light and scattered in nature to more widespread and steady heading into this afternoon. A rain/snow line will continue to move northward during the afternoon, likely stalling near or just south of Lake Winnipesaukee and coastal Maine.
Below: HRRR showing potential weather around mid-afternoon today:
The greatest potential for bands of moderate to briefly heavy snow will be just north of where the rain/snow line stalls. This will likely be for central and northern New Hampshire (Lake Winnipesaukee through the White Mountains) and across interior Maine. Current probabilities show a 50-80% chance of snowfall rates at an inch an hour in these locations. Here is where the greatest potential for picking up 2-5 inches will be located. Eastern Maine will likely end up as the jackpot zone and has the greatest chance for at least 4 inches.
A coating to a couple inches is expected elsewhere, with amounts dropping off generally moving southward in the region. Vermont will see the greatest forcing from the secondary low pass before it can create steadier precipitation, leading to lower totals than what will be seen in New Hampshire and Maine.
Widespread and steady rain and snow will continue through much of the day for all of New England. Precipitation will wind down from west to east starting late this afternoon for western areas. The backside of precipitation will gradually push eastward through the evening. Eastern Maine will naturally be in it the longest, taking until Monday night to shut down.
Below: HRRR showing potential weather this evening:
TUESDAY
The (weakening) primary low pressure system associated with Monday's system will pass to the north of New England on Tuesday. This will keep the region under broad cyclonic flow, though limited precipitation is expected. This will mainly create large puffy clouds in the afternoon for much of New England. The greatest chance for quick bouts of precipitation will be across the northern tier, closest to the center of the low. A downsloping effect will allow temperatures to tick a notch warmer than Monday.
Below: HRRR showing potential weather Tuesday afternoon:
WEDNESDAY
New England remains in a trough on Wednesday. Another disturbance will rotate through this trough, spawning an area of low pressure to the south of New England. This low will track northeastward up the New England coastline. Exactly how close to the coast this system gets will determine how expansive precipitation will be across New England and how much falls.
The greatest chance for more numerous showers will be near the coastline, with chances dropping off moving north and west. The exact extent of precipitation will all come down to where the coastal low tracks. We're reaching the point in the year where the jet stream begins to weaken and slow down, which causes model skill to drop in the early spring. This can lead to quick changes among forecasts that aren't usually seen at other times of year.
Heading later into Wednesday and Wednesday night, the northern trough as well as the coastal low (depending on evolution) may cycle some snow showers into northern New England, bringing a round of light accumulations for the northern tier. Amounts (of both rain and snow) are subject to increase or decrease given the significant spread in potential outcomes being shown, but will likely remain on the lighter end no matter what.
Below: Current probability of seeing at least an inch of snow from Wednesday morning to Thursday morning:
THURSDAY
Thursday will be the quietest week for much of New England. A ridge of high pressure will begin to build to the south of New England as the current trough slowly continues to push eastward. Skies will likely see variable clouds, dry conditions and seasonable temperatures. It could be breezy, however, as the pressure difference between the high to our south and the departing low to our east increases.
FRIDAY
A disturbance will pass to the north of New England Thursday night into Friday. This will drag a decently strong cold front across the region. This front will usher in a cooler air mass, particularly for northern New England. It may also trigger some scattered snow and rain showers ahead of it along with increasing winds. It will be a chilly wind on Friday as cold air advection begins.
WEEKEND
The unsettled conditions show no signs of ending as the next disturbance pushes eastward this weekend. Through the weekend, the system's warm front will likely try to push northward toward New England. This would represent the initial batch of precipitation ahead of the main system's arrival (which is trending toward Sunday or Monday). Whether this initial batch of precipitation is rain or snow will likely depend on its arrival time (coldest part of the day or during the afternoon once heating has happened).
Below: Current weather map for Saturday (March 29):
Overall, early trends point toward a potential situation where the system begins as snow for many before changing to rain from south to north. Overall, early guidance is leaning toward a warmer solution with more rain than snow across northern New England, but it's hard to have confidence in any outcome at this point.
It's very difficult to try to give any kind of details at this point given the massive spread in potential outcomes and timing. This could be an impactful storm with multiple precipitation types around New England. It could also be drawn out, with the main storm system potentially not passing through New England until next Monday (March 31).
Below: Current weather map for next Monday (March 31):
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