After a brief and weak ridge of high pressure for Saturday, another clipper system will approach New England for tonight into Sunday morning. This clipper system will be a much more standard version compared to the one this past Thursday. As the system passes to the north of New England, it will lift a warm front through the region. This front will provide the forcing for a period of snow showers.
Widespread light (to at times moderate) snowfall will break out generally from west to east starting this evening. Widespread snow will be ongoing across New England from midnight through sunrise. By around sunrise, snow showers will likely begin to break up and become more scattered. Snow will continue to break up and become more isolated through the morning with little if any activity remaining anywhere in New England by midday.
Below: HRRR showing potential weather very early Sunday morning (1st image) and around mid-morning (2nd image):
With snow showers being driven by warm air advection along a warm front, moisture will be limited with this system, which will help limit snowfall rates and overall amounts. New England is only looking at a 4-6 hour window for the potential of accumulating snowfall before forcing weakens along the passing warm front. Despite this, very high snow ratios (dry, fluffy snow) will make for easy accumulations during the rather brief time snow is falling.
Much of New England will likely pick up an inch or two of snow, with a bit more being squeezed out across the mountains. Downeast Maine may also see a bump of snowfall due to higher moisture content and better lift. Overall, amounts will be slightly higher across northern areas as forcing will be strongest near the warm front, which will likely settle across the northern tier.
Sunday afternoon will be milder than the past couple days thanks to a southwesterly flow set up by the warm front. Much of New England will rise above freezing with southern and central areas likely getting into the 40s. The exception to this will be northern Maine, who will likely stay well below freezing. These milder temperatures will begin to melt the freshly fallen snow.
New England's weather will remain unsettled through much of next week as a series of fronts move through the region, punctuated by a more organized system around midweek. The clipper system will drag its cold front across New England Sunday evening, but this should be barely noticeable and a dry passage. A warm front will approach New England, leading to a period of mainly light precipitation from Monday night through Tuesday.
This will likely feature a mixed bag, with rain showers across lower elevations of southern with a mix of rain and snow farther north and at higher elevations. A period of sleet and/or freezing rain will be possible as this messy system moves through. Precipitation looks to move through from west to east Monday afternoon through Tuesday morning. At this point, Tuesday afternoon is looking mainly dry outside of isolated showers. Regardless of precipitation type, accumulations of rain, snow and ice should be light.
The main storm system of this event will likely arrive Tuesday night into Wednesday. A strengthening cold front will approach New England ahead of a trough over the Great Lakes. A surface low pressure system will likely form along this front to the south of New England and move northeast through New England. This will set the stage for an organized storm system, bringing potentially bouts of moderate to heavy precipitation. As of now, guidance generally favors a winter washout storm for most.
As of now, the surface low is expected to track inland across New England. This favors a mainly rain event for much of New England. With that said, there is uncertainty in how temperatures will play out this upcoming week and a transition to wintry precipitation remains possible across the higher terrain. The track of the surface low will determine where the heaviest rain and highest winds occur as well as the extent and timing of a switch to wintry precipitation.
This system will have plentiful moisture to work with as it will have a connection to the Gulf of Mexico. That means that the potential is there for moderate to potentially heavy rainfall. While the region remains in a drought, this system could produce heavy enough rainfall rates to elevate flash flood concerns. The Weather Prediction Center currently has eastern New England in a "slight" risk (level 2 of 4) for excessive rainfall on Wednesday. Nothing is concrete and a more favorable storm track (less impactful) remains plenty possible.
Below: Precipitable water values showing moisture streaming northward from the Gulf of Mexico:
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