Yesterday we went into the upcoming temperature outlook for New England while briefly going into precipitation. Today, we'll do the opposite and go deeper into precipitation chances during this upcoming stretch. Upslope snow showers across the mountains will gradually wind down as today goes on. Heading into this weekend, the weather will begin to turn a bit more unsettled before Arctic air arrives.
The very next chance for flakes to fly will be overnight Thursday into Friday morning as a subtle disturbance scoots through the region. This will mainly create an increase in clouds Thursday afternoon and night, but they may be able to spit out a few flakes at times overnight. The next chance for more widespread precipitation will come as a frontal system approaches this weekend, bringing rain and snow showers across the region.
A warm front will push through New England Saturday morning followed by a cold front later Saturday into Sunday morning. The warm front will allow for a gradual warm-up during the day with much of New England rising above freezing. Southern and central areas may be able to push well into the 40s. Showers will begin to break out ahead of the cold front Saturday afternoon and push west to east through the evening and overnight hours.
Moisture is meager with this system, with QPF ranging from 0.01-0.1 inches, indicating the potential for nothing more than light, scattered precipitation. With marginal temperatures across interior New England and the mountains, this precipitation will likely be a rain/snow mix or snow showers. Very limited moisture means accumulations of both rain and snow will be very light.
Below: CMC showing potential weather around Saturday evening:
The system's primary cold front will likely have cleared the region by Sunday morning. A secondary, Arctic front will quickly follow the primary front. This will result in dropping temperatures for the start of next week, however, the drop does appear to be more gradual, allowing Sunday's highs to reach respectable mid-winter levels.
Heading later into Sunday, a surface low will be looking to develop along the cold front. At this point, the front will likely have cleared New England and be offshore. Where this area of low pressure tracks will come down to the location of the cold front since the system will be moving along it. Depending on where it tracks, a period of light snow will be possible, mainly for southern and central New England.
Where the low tracks will all come down to the timing and location of the cold front and the colder air behind it. This will determine how offshore this system tracks. Depending on the exact track, it could bring a quick-hitting period of light snow, or a rain/snow mix. Should the push of colder air be stronger, it will suppress the system well offshore. The system has a much lower chance of affecting the northern tier of New England.
Below: Current probability of impactful winter weather Sunday afternoon into Monday morning
Despite the timing and track differences that remain among guidance, this appears poised to be a weaker and quick-hitting event. Should it take a favorable track for a period of snow, it will likely result in accumulations on the lower end. An unfavorable track would lead to nothing much at all or more of a mix/rain event for portions of southern New England. The system would enter the picture late Sunday and likely wrap up by Monday afternoon.
Below: Model roundup (Euro, GFS, CMC and GraphCast) for early Monday morning:
Once the Arctic air settles in, any and all precipitation chances will end as the coldest air masses are the driest ones. The core of the cold air will likely be with New England from Monday evening through at least Wednesday. This time will likely see mostly sunny skies with bitter temperatures in the single digits and teens during the day with single digits lows, on either side of zero.
Looking at the long term, a southern stream storm system is appearing poised to develop around early to mid next week near the Gulf of Mexico. This could bring the south another winter storm next week. Where this storm goes from the south is anyone's guess at this point. Whether or not it hugs the coast and comes up to the northeast or remains well offshore will likely come down to the timing of the Arctic air. Should the Arctic air mass hang around, it would likely stay offshore later next week, but this is trying to look out too far to get into any kind of detail.
Below: Current Probability of impactful winter weather next Tuesday to Wednesday (January 21-22), showing the potential for a storm system to develop in the south:
As we begin to enter the annual period where large-scale winter storms are the most common (most major winter storms in New England strike from January 15th to March 15th), odds do point toward at least one major snowstorm occurring at some point over the next couple months. Should the pattern that has supported a persistent ridge-in-the-west-trough-in-the-east setup for the better part of a month now remain in place, it would only be a matter of time before a favorable storm track occurs.
Another note to mention are ocean temperatures. The waters off New England's south coast are currently below average while waters farther south are above average. This difference does favor cyclogenesis of coastal systems. The question is how strong can storms get and how quickly as well as how close they can track to New England. This will be something to watch as we push through the height of nor'easter season. The biggest limiting factor will be if it remains too cold and dry as it has been. New England will need just the right balance.
Below: Current ocean temperature anomaly:
