Over the next week (at least), New England is looking at a busy weather pattern. The way this pattern is set up will make precipitation types and timing rather tricky when it comes to changeovers from snow to mix to rain across New England. There are two main factors setting up this pattern, both working with each other to bring this busy pattern together.
The large-scale setup over the United States begins with a Rex Block over the west coast with a large and persistent ridge of high pressure over Alaska with a closed low over the northwest United States. A Rex Block occurs when a high pressure system sets up directly north of a low pressure system, with the low pressure system becoming blocked. Without blocking over Greenland, this will shove a fast, zonal flow across the rest of the United States.
Below: Upper-level flow pattern across the United States on Tuesday, showing a clear Rex Block over the west with zonal flow opening up for the rest of the US:

Zonal flow is the opposite of meridional (or amplified) flow. Zonal flow occurs when the jet stream lies mostly flat over the United States without any major ridges or troughs. Meridional flow is the opposite, which is when the jet stream becomes more wavy and develops deeper ridges and troughs. Oftentimes, zonal flow can lead to quieter and low impact weather, however, the block over the west coast has opened up an atmospheric river for the northern west coast. With zonal flow in place, this will allow a parade of storms to March across the country.
This began over the weekend with clipper systems moving through on Friday and Sunday nights. It will continue this week with storms on Thursday, Saturday night and likely around the middle of next week. Up first is the messy Thursday storm. This frontal system's primary low will pass to New England's north while a secondary low passes near southern New England. This will yield a messy mix of precipitation across New England.

The basic thought process with this storm hasn't changed much over the past couple days. That is to say the storm will likely begin as a burst of snow for everyone in New England when the storm arrives Thursday morning. A gradual changeover to a wintry mix and eventually plain rain will occur through the afternoon and evening from south to north.
Much of northern New England will likely remain mostly snow, with the most mixing potential across southern New Hampshire. There remains uncertainty on just how far north the cold air erodes, allowing for a wintry mix to develop. There's also some uncertainty on how far north in southern New England the plain rain gets. It will likely take much of the day for plain rain to develop, with many seeing snow or a mix well into the afternoon.

Without a cold high pressure to the north of New England, there isn't a strong feature to keep cold air at the surface. With an increasing southerly flow, temperatures aloft will be warming while surface temperatures remain colder. This is the perfect recipe for mixing (sleet and freezing rain). Cold temperatures are often stubborn to budge, so it may take time for the switch to snow.
With snow changing over from south to north, snowfall totals will increase from south to north as northern areas will stay in the snow the longest. The progressive nature of the storm and the lack of amplification for strengthening will preclude significant totals. A jackpot zone of 3-6 inches is likely across central New England with amounts tapering off to the north (due to lighter snowfall) and south (due to mixing).
Below: Current probability of seeing at least 2 inches of snow by Friday morning:

At this point, freezing rain accretion appears to be light. A period of freezing rain will be most likely during the transition from snow to rain across southern New England. Freezing drizzle will also be possible as the storm pulls away across northern New England, even in areas that saw snow for much of the storm. While the ice expected isn't expected to be enough to cause any real impacts, it will create extra slick surfaces on top of frozen precipitation that preceded it. Overall, it will be a raw and messy day.
Below: Current probability of at least a glaze of ice by Thursday night:

This storm will be a quick-hitter, very similar to our previous few storms. The impact with this one will be higher simply because it's coming through during the daytime instead of the overnight, like the last few. The storm arrives across southern New England Thursday morning and quickly spreads northeast through the afternoon.
The storm will wind down from southwest to northeast Thursday evening and night. Zonal flow supports quick-moving systems as limited blocking allows them to shoot across the country and out to sea without getting hung up near New England.
Below: CMC showing potential weather around midday Thursday (1st image) and early evening (2nd image):
Precipitation types with this storm (and future storms) are tricky due to the newly formed storm track. In January, the storm track was generally to New England's south. This set up a persistently cold month, but with limited storm activity. Heading into February, the storm track has shifted to coming straight through New England. This sets up a baroclinic zone over the region.
A baroclinic zone is an area where a temperature gradient exists on a constant pressure surface. Naturally, the colder air is on the north side of the zone with milder air to the south. This can lead to larger temperature differences over a rather small area. In this case, that smaller area is New England. This leads to very changeable temperatures with up and down swings as the cold air mass to the north battles with the milder air mass to the south.

As stated before, this setup promotes an active pattern across the country. This will keep systems moving through New England every few days. With that said, there will be breaks between the storms as high pressure systems will quickly cross New England between the low pressure systems. New England's next storm will likely play out Saturday night to Sunday.
With the pattern remaining in place, this storm will likely play out similar to the Thursday one. The baroclinic zone may shift a bit south, leading to a colder solution than Thursday, though mixing still appears to occur across southern New England.

Better dynamics and more moisture also means there will be a chance for higher precipitation rates and accumulations. The storm will likely be another quick-mover as well, likely in and out of New England over the course of 12 hours.
Below: Current likelihood of winter weather impacts Saturday night into Sunday:

Looking into the longer term, the Rex Block over the west will likely break down, however, the large ridge over Alaska looks to remain in place. Without blocking near Greenland, this will continue to support a flat, zonal flow across the United States. This, in turn, favors the active pattern with changeable temperatures continuing.
Below: Projected jet stream flow heading into next week, showing a continued flat flow:

The next organized storm in this stretch will likely come around the middle of next week. Around this time, some amplification of the jet stream may begin to form, allowing a track farther south or offshore. Over a week out, there's (obviously) no need to try to go into specifics, especially when we have two storms in front of us before then, but the timing fits given the active nature of the pattern that is unlikely to break down before then.
Below: Projected jet stream flow heading toward the end of next week:

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