The anti-rain force around New England will hold strong on Thursday as a weakening area of low pressure across the Great Lakes will get shoved well to New England's south this afternoon and evening. This will keep any and all precipitation associated with it to the south as well. This system will be pushed away thanks to a strong area of high pressure to New England's north.
While this system dives southward tonight, a storm well to New England's east will be gaining strength as it cuts off from the main flow due to a blocking high. This system will begin to move in a northwest direction toward Nova Scotia, closer to New England, tonight and Friday. Most of New England will basically be caught in the dry slot between these systems. With that said, the storm system moving back toward Maine will bring some precipitation to eastern areas.
The air mass over much of New England will remain very dry between these systems, so precipitation chances will be very limited to none for most of New England on Friday. The exception to this will be Maine. With the cutoff low gradually backing toward Nova Scotia, precipitation chances will increase from east to west across the state beginning Friday morning.
Precipitation is currently looking to begin backing into eastern Maine around daybreak before gradually pushing westward through the morning and into the afternoon. Precipitation is currently looking to be on the light and scattered side rather than the steady side. The timing of when precipitation breaks out is important in regards to the type of precipitation.
Surface temperatures tonight will be dropping into the 20s across Maine. Should precipitation break out early enough in the day, it may begin as light freezing rain. This would come as warmer air wrapping around the low would rise over the sub-freezing air at the surface, creating an environment favorable for some very light icing. Whether or not this happens will come down to timing and just how much moisture gets wrapped around the system. Any freezing rain will transition to plain showers as the morning continues.
Below: Potential weather Friday morning (1st image) and Friday afternoon (2nd image):
Cutoff lows always come with added uncertainty since they are cut off from the main flow. This allows them to do basically whatever they want, which can make it difficult to pin down details. In this case, some models are showing a later start time to precipitation (more late morning instead of daybreak). Should this later start time occur, it would really limit the potential for frozen precipitation since surface temperatures would likely have largely risen above freezing by that time, leading to plain rain showers at the onset.
Due to the potential of a glaze of ice, the National Weather Service has posted a (very) low end winter weather advisory for eastern Maine. The advisory has been posted since this is the first potential widespread frozen precipitation event of the season. If this exact situation occurs a month from now, it likely wouldn't get an alert.
Outside of Maine and maybe northern New Hampshire, it may be difficult to get an increase in clouds, never mind any showers. Speaking of cloud cover, just how much (or how little) of the sky will be clouded for New England outside of Maine will come down to exactly where the cutoff low goes. Even Maine will likely see limited measurable precipitation. With cutoff uncertainty, just how far west the precipitation pushes won't be fully known until it begins to arrive.
Other than the precipitation for Maine, the cutoff low will lead to breezy conditions for all of New England. With high pressure building to the west of New England and low pressure retrograding back towards the region from the east, a gusty breeze is possible. It won't be Tuesday level winds, but a stubborn breeze will hang around all week. This will allow for fire risk to be elevated once again for southern New England. It wouldn't be surprising to see yet another red flag warning posted for Friday.
Tides will also be approaching monthly astronomical highs Friday into the weekend. A coastal flood statement has been issued for much of the southern and central New England coasts for splash over. These statements may carry over to the weekend. A low end coastal flood advisory may be posted for Friday and/or Saturday.
The cutoff low currently looks poised to swirl around to the north of Nova Scotia through Saturday. Showers will be most numerous Friday morning and gradually decay and become more and more isolated through Saturday for Maine. New England's next chance for precipitation will come Monday as a weak and fast moving frontal system moves to the north of the region, bringing the potential for very light showers with little to no measurable rainfall.
Below: Weather map for Monday (November 18):
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