Updated 7:45pm January 5. Evening updates are in bold.
New England's winter storm is currently diving toward the Gulf of Mexico. The storm will lift out of the deep south and work up the coast in a typical nor'easter fashion and arrive in New England for this weekend. The storm will likely track between Cape Cod and the benchmark on Sunday. This will result in higher snow totals across the interior with lesser amounts as you work toward the coast.
ALERTS
TIMING
The daylight hours of Saturday will be dry for everyone. Snow showers will begin to move in from southwest to northeast throughout Saturday evening and into the night. Some ocean-enhanced snow showers will be possible in the evening across parts of eastern New England before the main storm system arrives.
Expected weather Saturday evening:
While the air will be cold enough to support an all-snow event for most, areas near the coast of southern New England will likely start the storm as an initial onshore flow off the ocean will keep more mild air around for the onset of the system. Snowfall rates will begin to ramp up Sunday morning and likely reach peak intensity early Sunday morning through sunrise (1am through 7 to 8am). There will likely be a sharp cutoff in steady snow at this time as you head north.
Expected weather overnight (1st image) and around sunrise Sunday (2nd image):
The storm's energy is elongated with two troughs likely lifting through New England from Saturday night to Sunday night. This will allow for a longer-duration event, with 24 hours of snow (in varying intensity) for New England. This will allow snow to continue well after the peak of the storm, through Sunday.
Snow will continue at a light to moderate rate through all of the daylight Sunday and into the evening. During this time, colder air will push southward, allowing the rain/snow line to be pushed further south back toward the southern New England coast. Snow will gradually taper off from west to east starting Sunday evening. Pretty much everyone should be done with the snow by midnight.
Expected weather Sunday early afternoon (1st image) and evening (2nd image):
Typical upslope snow showers in the mountains will likely continue through Monday before ending. Monday will return to a dry day for everyone else as high pressure builds back in.
SNOW
The jackpot zone for this storm continues to look like it will be southern New Hampshire, southern Vermont and interior Massachusetts and Connecticut. These areas will stand the best chance at seeing a half foot or more of snow. Snowfall rates of 1 to 1.5 inches an hour may be possible for a brief time early Sunday morning. Rates will back off for the afternoon.
The track of the low has trended a bit further north today. This has pushed the higher amounts further north on our map, which is the biggest change from this morning. This is also evidenced by the expansion of winter storm watches into central New Hampshire and Vermont.
Heading toward eastern Massachusetts and the south coast, things get a bit questionable. Snowfall amounts will very likely be lower there due to initial rain and mixing. The snow itself will also be the heavier, wetter kind, which compresses as it accumulates, making it more difficult to pile up. We've left these areas alone from this morning on the snow map. We'll be watching the overnight trends for the morning update.
Much of western and central Massachusetts and Connecticut, as well as southern Vermont and New Hampshire will likely land in the 6-10 inch range, with localized areas up to a foot where the most intense morning snow bands set up.
Colder air from the north will likely rush into these areas as the winds shift to the north, which will gradually change rain and mixing over to snow. How quickly this happens will be key in the final snowfall totals in eastern and coastal areas of southern New England. Should this take longer than anticipated (which it could due to an onshore flow), it would lead to lower totals. If the process speeds up, it will be the opposite.
Over the past 24 hours, the trends have been for the storm to deepen a bit further to the east with the two troughs mentioned in the "timing" section not phasing until the storm gets to our east. This would result in a bit lower snow totals across the interior. This is the main way the storm could bust.
The northern tier of New England will remain well away from the storm's center, no matter where the exact track ends up. This, along with the rather compact nature of the system, will result in much less snow in these areas despite the northward trend in the track.
WIND
Winds will become gusty near the coast, though not overly strong for most. Gust of at least 25mph will be possible well inland with gusts reaching toward 40-50mph near the coast. The best chance for 50mph gusts will be along the Massachusetts South Shore and Cape Cod. Wind advisories may be posted for these areas at some point.
While these gusts on their own normally wouldn't cause too much of an issue, combine it with wet, sticky snow in the areas expected to see the highest gusts and some power outages could result. This will not be a widespread power outage event.
FLASH FREEZE
The main area where flash freezing could create some problems is across eastern Massachusetts and Rhode Island. These areas will see an abrupt wind shift from easterly to northerly. This will drop temperatures Sunday afternoon, causing rain that has fallen to freeze and allow for snowfall. All of New England will see temperatures drop in the afternoon as the storm pulls away, but northern and western New England will already by around freezing when temps drop.
THE NEXT STORM
Another impactful storm is looking to cross the region late Tuesday into Wednesday. This storm could rapidly intensify as it approaches New England, producing heavy precipitation and potentially strong winds. With a trend toward a more mild storm, a widespread 1-3 inches of rain will be possible. Combine this with fresh snowmelt and there could be some flooding concerns in southern New England.
The storm could start as a burst of snow for most before a quick changeover to rain. This would occur as there is plenty of cold air in place initially, but with an expected interior track of the storm, a southerly flow would change snow over to rain for most. If a secondary, coastal low develops, it would lock in the colder air, allowing for more wintry precipitation. Models have generally been trending away from this happening, but this far out, it's still on the table.
The wind threat with this storm is a wild card with factors working for (strong low-level jet, robust storm system) and against (inversion, cold boundary layer, potential surface low) strong to damaging winds. This will be worked out in the coming days.
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