The week is starting off as more of the same with dry and generally mild conditions (by mid-November standards). Heading toward the end of the week, things are finally looking to change pace with the region's best chance at widespread rain in quite some time.
MONDAY
A decaying system will pass to the north of New England on Monday, dragging a weakening cold front across the region. After the morning line of scattered rain and snow showers, scattered upslope showers will continue through the afternoon in the mountains. Outside of the mountains, skies will begin to clear behind the front. It will be another breezy day once the front clears the area. With the weak nature of the front, there won't be an air mass change, so temperatures will be very similar to the weekend.
Below: GFS showing the potential for upslope showers Monday afternoon:
TUESDAY & WEDNESDAY
High pressure and ridging will build into New England ahead of a deepening trough in the Great Lakes. This will provide quiet and dry weather with mainly sunny skies for southern and central New England. There will generally be more clouds across the northern tier of New England during this time.
The breeze will gradually slacken throughout this period as well, with somewhat breezy conditions on Tuesday followed by quiet conditions on Wednesday. Highs will cool off a notch from Monday for most with afternoons in the 40s across northern New England to the 50s across central and southern New England.
THURSDAY & FRIDAY
Wednesday night into Thursday morning, a deepening trough near the Great Lakes will spawn a surface low pressure system just to the south of New England. This will rotate around the upper low on Thursday, allowing for a period of widespread rainfall on Thursday into Thursday night. The closed, upper-level low will continue to meander around New England Friday and likely into Saturday as well, bringing an extended period of unsettled weather after a widespread rainfall on Thursday.
Strong dynamics with the system will be able to act on increasing moisture, allowing for a band of widespread rainfall to move across New England early Thursday morning through Thursday night. The band will move from southwest to northeast, with most getting in on it during the day Thursday. Northern and eastern Maine may have to wait until after sunset on Thursday as the band continues to push north and east during the day. Trends have generally been toward a later start time on rainfall on Thursday.
Below: ICON showing potential weather early Thursday afternoon:
The surface low and associated occluded front will continue to lift north Thursday night and into Friday morning. This will continue to spread the batch of steady rain northward into northern and eastern Maine during this time. The rest of New England will likely transition to more scattered and showery weather as the upper low moves overhead and hangs around for the day Friday.
A big question going into Thursday night and Friday will be the potential for higher elevation snow showers. This remains a large wild card as the track and intensity of both the upper-level low and surface low will play a large role in how much colder air can get wrapped into the backside of the system. Depending on how quickly the colder air can wrap in, the Greens, Whites and Berkshires could see some snow accumulations by Friday night. Just how low in elevation it can get remains to be seen. This will become more clear by midweek.
As far as total precipitation for the storm, New England is likely looking at a widespread half an inch to an inch of rainfall. Atmospheric moisture doesn't look to be overly high, which should help to keep totals in check somewhat. Much of New England is running several inches below average in rainfall for the fall season, so this won't be a total drought-buster, however, it is a drought-denter and will certainly help with the fire risk.
Below: Weather Prediction Center precipitation forecast for Thursday morning to Friday morning:
Over the past several weeks, we've watched what could have been decent rain events shrivel up into mere isolated shower chances. Is there a difference with this one that promotes a higher confidence? Yes. There is a clear indication of high moisture from the Gulf of Mexico streaming northward into the system this week, as seen in precipitable water (shown below).
WEEKEND
The weekend will likely feature a very gradual trend toward drier weather. As of now, Saturday is looking to feature left over, spot showers for southern and central New England with more numerous showers in the mountains. Sunday is currently looking mainly dry with a clearing trend. This is a general blocking pattern that we'll be in and guidance can have a tendency to clear out systems faster than reality in these setups, so it wouldn't be overly surprising to see the weekend trend a bit wetter or at least slower to clear out.
Below: Current weather map for Sunday morning (November 24):
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