A wave of low pressure will quickly develop today along a slowed cold front that is crossing through New England and track northeastward. This will allow for a period of steady snow across a wide swath of the region with a period of locally heavy snowfall this evening and overnight. The storm will be strengthening as it passes the region.
ALERTS
TIMING
Snow, and possibly rain along the coast, will likely begin to break out across southwestern New England around mid to late afternoon Sunday. The storm will steadily move northeast, lifting its shield of precipitation northeast across New England at a decent clip. By the early evening, snow will likely have spread across all of southern and central New England and begin pushing into western Maine.
Below: HRRR showing potential weather around mid-afternoon today (1st image) and early this evening (2nd image):
By the middle of the night, the storm will likely make its closest pass to New England. Trends have generally been toward a track offshore rather than over Cape Cod. The evening through the overnight is when snow will be the most widespread across New England and the heaviest snowfall rates occur. There will likely be a brief window of 1-2" an hour snowfall rates across interior southern New England and the northern New England coastal plain. The rain/snow will steadily move closer to the immediate coast/Cape Cod.
Below: HRRR showing potential weather around midnight:
The storm is very progressive and will be racing up the coast through the morning. Snow will likely quickly begin to break up from southwest to northeast during the pre-dawn hours. By sunrise, a bulk of the snow will be centered over Maine. Snow will continue to break up in Maine through the morning with all of New England cold and dry by the afternoon. The sun may even begin to come out by sunrise in southern New England.
Below: HRRR showing potential weather around sunrise Monday:
SNOWFALL
Trends over the past 24 hours have seen much more agreement on the track of the low pressure system. Overall, there has been an eastward shift in the storm's track over the past 24 hours. This shift has been more noticeable on models that were showing the storm pass right over Cape Cod. All major mesoscale models have the storm passing offshore in the vicinity of the benchmark.
The general eastward trend has shifted the overall snowfall a bit southward compared to last night's update. The storm is still poised to come close enough to bring a very wide swath of 4-8 inches of snow across most of southern and central New England. Only the northern tier and the South Coast are likely to see less. The most snow will likely fall across interior southern New England, southern New Hampshire and Downeast Maine, with Downeast Maine being the likely jackpot zone.
The eastward trend, along with the quick movement of the storm has lowered confidence in the chances of exceeding 8 inches across Connecticut, Massachusetts and New Hampshire. With that said, there could be isolated spots to 10 inches where snow banding is more persistent, but the chances aren't widespread enough to include an 8-12" zone in these areas on the map above.
The storm will be strengthening as it moves northeast. How quickly and how strong the storm gets will play into totals. Since the storm will have the most time to strengthen before reaching eastern Maine, confidence is higher in 8-12" totals there, so we limited that zone to interior Downeast Maine.
Below: Current probability of seeing at least 8 inches of snow. For the record, Probabilities of seeing a foot top out at 30% for Downeast Maine and 10% for the rest of New England:
This is a favorable setup for a decent thump of snow across New England. An organized, closed low will likely develop, which will strengthen quickly as it passes the New England coast. This will occur as a strong upper-level jet will be over the region while this low strengthens. This will help create frontogenesis and allow for a period of intense snow banding. The snow banding is supported by a high moisture content within the atmosphere. All of this combined is conducive for a decent snow event.
The only limiting factor is the storm's quick speed. This is shaping up to be a 12 hour storm system for New England all together with a much shorter window for the steadiest snow to fall. This will help to hold snowfall in check.
There will be a brief period where 1-2 inch an hour snowfall rates will be possible, known as mesoscale banding. These bands of more intense snow are looking likely to set up across northern and central Massachusetts, interior southern New Hampshire and just inland from Maine's immediate coast. There may be two main bands across southern New England; the main one mentioned above with another one possibly setting up near southeast Massachusetts and Rhode Island, near the coastal front (where the 20° temps meet the above freezing temps).
Another factor for snowfall will be the high snow ratios. Strong cold air advection will be taking place during the storm with temperatures dropping throughout the event. This will support a light and fluffy snow for most. Southeast Massachusetts and Rhode Island will see heavier snow, but even there may be able to end with a lighter snow. This kind of snow piles up quickly and easily. With 1+ inch an hour snowfall rates for a time, this will allow for rapid accumulation.
Below: Hourly temperature from mid-afternoon today through the pre-dawn hours Monday:
BUST POTENTIAL
The main bust potential will come from track and strength issues. Should the storm take a more easterly track than expected, the storm will not get as strong and the highest snowfall would not be able to be realized. Also, if the storm remains an open wave throughout instead of developing a closed low, this would result in lighter snowfall rates, keeping snowfall down. The quick motion of the storm is also a limiting factor for snow totals regardless of how strong the storm is able to get. Bust potential has lowered to moderate given everything working in favor of higher snowfall discussed above.
WIND
A period of gusts of 25-35mph will be possible, especially near the coast. This isn't an impactful wind, but it will cause some blowing snow given the fluffy nature of the snow. Blowing snow could significantly reduce visibilities for a time tonight, especially across eastern Maine, where snowfall rates will be most intense.
ARCTIC BLAST
The Arctic blast of air coming next week will likely peak (or bottom out) Tuesday and Wednesday, though Monday and Thursday will still be very cold. This blast will likely be deep and widespread across the central and eastern United States. Tuesday and Wednesday will likely see high temperatures in the single digits north to teens south.
Overnight lows will be in the single digits, on either side of zero. There will be a chance the coldest hollows of northern New England (mountains, Northeast Kingdom and northern Maine) will drop into the -10s. Wind chills will drop below zero during this time region-wide with minimum values potentially reaching for the -15 to -30° range. Winds won't be strong, but even just breezy conditions (10-20mph on Tuesday and Wednesday) with these temperatures will knock the feels-like temperatures down. Winds will be most noticeable on Monday.
BEYOND
Looking at the long term, a southern stream storm system appears 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 remains up in the air 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. A quicker departure of the arctic air would allow a window where the storm could sneak into the region late next week. It may also try to phase with a northern stream system moving across the Great Lakes. A majority of guidance keeps the storm to the south, resulting in a glancing blow or miss altogether. It will be something to watch in the coming days.
Below: Current Weather Prediction Center probability of impactful winter weather next Friday (January 24):
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