Despite the cold and dry air mass over New England this week, broad cyclonic flow and general troughing will allow for bouts of snow showers through the week for select locations. This stubborn blocking pattern that the region is in will remain in place through the week, leading to very little variation in the weather from day to day. This pattern is showing signs of breaking down by next weekend.
Below: Flow pattern through around midweek showing the general blocking patterns we're in, known as a Rex Block (when high pressure sits directly north of low pressure):
In the near term, a well-developed storm system will get shoved south of New England thanks to the strong, cutoff low pressure system to New England's northeast (seen on the map above). This system will leave no room for the impactful system to our south to inch north. With dry over southern New England, almost all precipitation will remain south of the region. It remains possible that the very northernmost bands push into Connecticut and Rhode Island, amounting to very little, if any, accumulations.
Below: GFS showing potential weather around midday Monday:
With a large, cutoff upper-level low sitting to New England's northeast combined with a persistent northwest flow will allow for bouts of scattered mountain snow showers through midweek, with the biggest break coming on Monday. These snow showers will ebb and flow in intensity and it won't be snowing 24/7 in the mountains. A subtle disturbance will rotate around the upper-level low Monday afternoon into Tuesday morning. This will come as the upper-level low retrogrades westward, closer to New England, during this time.
This period (Monday night-Tuesday) will likely see the most widespread and continuous snow showers activity in the mountains and northern Maine. This period is also when flow over the mountains is most likely to become unblocked, allowing some snow showers or flurries to get south of the mountains, though no accumulations are expected south of the foothills. Snowfall amounts will likely be greatest over the northern Green Mountains, where increased moisture will be likely due to the westerly flow off the unfrozen Lake Champlain.
Below: Probability of at least an inch of snow from Monday night to Tuesday night:
Southern and central New England (including the entire coastal plain) will remain just about snow-free during this time (Monday afternoon-Wednesday) with variable clouds. Another disturbance may rotate in on Wednesday into Thursday, keeping the upslope snow showers going for the mountains. This may also allow for a few snow showers to slip south of the mountains once again, but, again no accumulations are expected.
Below: CMC showing potential weather from sunrise Monday through midweek:
The large and strong blocking high over Greenland shows signs of breaking down heading toward the end of this week. This will allow the upper-level low to weaken and slide eastward, away from New England. This will provide a break from snow showers across the entire region, even in the mountains, for Friday and likely the start of the weekend.
There's been some buzz about a potential nor'easter next weekend that could bring a widespread snowstorm to New England. This is based on recent operational model runs of the Euro and GFS that have a strong coastal storm passing New England sometime around next Sunday. With that said, these model runs/snapshots need context.
Heading into next weekend, a pattern change will likely occur, with the Greenland Block weakening. This will allow the current stalled system to leave late this week and re-open the door to other systems. Around next weekend, a northern stream system may approach the region while a southern stream system works up the coast. The level of interaction (or phasing) between these systems will determine impacts in New England.
Below: Current weather map for Saturday morning (January 11):
Less phasing would keep the moisture rich southern system to New England's south, resulting in minimal impacts. More phasing would result in a more widespread and impactful storm. These phasing storms are complex and models can struggle to figure them out within 3-4 days, never mind 7-8. With that said, models will continue to vary widely with each other and from run to run over the next few days. The CMC does not show this storm developing as of now and many individual ensemble members are not on board with formation.
What these operational model snapshots from the Euro and GFS don't show are trends, exact track, exact timing, large-scale flow pattern, mesoscale snow banding, snow ratios, temperature profiles, potential secondary low development and individual ensemble member outcomes, among other factors. So, the takeaway is that there's no need to get worked up in the slightest this weekend about a potential snowstorm that may or may not happen next weekend.
Below: Probability of impactful winter weather next Sunday. This will shift and wobble around through the week:
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