Mid-AM All Zones: Multiple wintry events in New England

An active pattern, which has existed across the Eastern United States for the better part of the past 3 months, will kick into even higher gear later this week into the early part of next week, as multiple disturbances drive southeastwards from Canada into New England. These disturbances in the mid and upper levels of the atmosphere will aid in the development of surface low pressure systems, first moving through Southeast Canada and then redeveloping off the coast of New England.

Exactly where and when these surface low pressure systems develop will be the critical component to wintry weather potential in Southern New England — including parts of Central and Northern Connecticut from Friday Night into Saturday morning and again from Sunday Night into Monday morning.

Snow will spread throughout New England later today and tonight with light accumulations likely.

Snow will spread throughout New England later today and tonight with light accumulations likely.

Backing up a bit, fair weather is expected to dominate the majority of Friday throughout the area. Temperatures will remain quite chilly and cold throughout the region, especially in areas where snow cover is deepest. Blustery winds may continue throughout the early and middle part of the day as well, but will subside as high pressure builds into the region briefly.

By evening, another storm system will approaching the region from the northwest. This low pressure area will be driving from Southaest Canada into New England, eventually to a position off the coast of New England. The storm system is not deep or amplified, and will remain very progressive. But bands of snow are likely to move from New York State through Southern New England tonight, possibly clipping parts of Northern New Jersey, NYC, and Long Island. The event is not expected to be impactful for zones which are further south, particularly over Southeast PA and Southern/Central NJ. Any impactful snow will be well to the north of these regions.

Accumulations should range from 1-3″, with the potential of up to 5″ in the higher elevations of New England by Saturday morning. Moisture will linger for a bit on Saturday morning across New England as the low pressure system develops well to the east. This moisture will eventually be shunted to the east as another low pressure area forms to the southwest of the area.

Snowfall Forecast for Friday through Saturday AM.

Snowfall Forecast for Friday through Saturday AM.

A bigger storm possibility late weekend

A strong mid and upper level disturbance will move from Southeast Canada into New England on Sunday — the emphasis on this one being strong. The disturbance is quite amplified and energetic, and will force the development of a very strong low pressure system off the coast of New England late Sunday Night into Monday morning.

The caveat(s) in the development of the storm begin with the initial low pressure area, which will develop over Southeast Canada. This ensures that warmer air will move through much of the Northern Mid Atlantic, via southwesterly winds. Warmer air will move northward — all the way into parts of New York State and Connecticut. But colder air hanging on north of there — from the latitude of Boston northward — will lead to wintry prospects even on the front end of the system.

GFS model showing the evolution of the storm system late this weekend in the mid levels of the atmosphere.

GFS model showing the evolution of the storm system late this weekend in the mid levels of the atmosphere.

The development of the secondary  low pressure area becomes the main concern with the forecast. The European model, which was showing a very strong storm system developing near the coast of New England, has shifted eastwards a bit this morning, more in line with the GFS model which had been showing a slightly further east development all along.

The location of the low pressure development is critical: The low pressure system will be quite strong as it redevelops off the coast, and bands of wintry precipitation are very likely to tuck around the northwest side of the system. If it is further offshore, impacts will be less in Southern New England, and mostly limited to Maine. A stronger storm system would lead to more widespread impacts, with the potential for very strong winds as well.

Our current forecast favors a slightly east/northeast development of the storm system due to the progressive nature of the mid and upper level atmospheric pattern. That being said, wintry weather is likely across Southern New England during this period, with significant snow and wind still likely in parts of Vermont, New Hampshire, Northern, Massachusetts and Maine.

Threat Analysis for Sunday PM through Monday AM event.

Threat Analysis for Sunday PM through Monday AM event.