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Potential for intense Northeast winter storm this weekend

A bomb cyclone could develop, with blizzard conditions for some areas not out of the question

European model simulation of storm off New England on Saturday. (WeatherBell)
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This article was last updated on Monday. For the latest on the storm based on information available Tuesday, see: Nor’easter could wallop New England with heavy snow and wind Saturday

Computer models are coming into agreement that a powerful winter storm or nor’easter will form off the Mid-Atlantic late this week and charge up the East Coast over the weekend. The storm has the potential to produce very heavy snow and strong winds, especially for areas north of Maryland into New England.

While the exact track of the storm is uncertain, New York, Providence, Boston and Portland could see serious effects.

“[T]he risk of a coastal storm passing near or east of Southern New England continues to increase,” wrote the National Weather Service office serving Boston in a discussion Monday. It cautioned, however, that it’s too early to specify how the storm will affect particular locations. Some model simulations still suggest the storm could track far enough east for just a glancing blow to the Northeast and New England.

Uncertainty as to what the storm might bring increases even more toward the Mid-Atlantic. Some model forecasts indicate a sharp cutoff in precipitation around the Baltimore-Washington area and to the west and south.

Right now, however, the more reliable models suggest that this storm could be a blockbuster for the zone from roughly Long Island to eastern Maine. If current forecasts are correct and do not change drastically, very heavy snow and strong winds could create blizzard conditions in some areas. Nearer the coast, snow could mix with or change to sleet and rain, depending on the storm’s exact track. Coastal flooding could also be an issue as winds drive ocean water and waves into the shore.

Model simulations project that the storm will probably meet the criteria of a “bomb cyclone” or one that intensifies at breakneck speed as it races up the coast.

As the storm will be moving swiftly, it may limit the potential for historically significant amounts of snow; however, totals of at least 6 to 12 inches seem plausible in some areas, assuming the storm doesn’t remain too far offshore.

Here’s an initial look of what’s possible in different population centers, with the understanding that overall forecast confidence is still low:

Washington and Baltimore: Most model simulations develop the storm far enough to the north and east that snow misses the region or just light-to-moderate amounts fall, mainly Friday night into Saturday morning. However, there are some outlier simulations that show more significant effects and the potential for at least six inches.

Chance of at least 1 inch: 30 percent | Chance of at least 3 inches: 20 percent | Chance of at least 6 inches: 10 percent

Philadelphia: Being farther northeast than Washington and Baltimore, the chance for measurable snow increases here — most likely falling late Friday night into Saturday as winds also become gusty.

Chance of at least 1 inch: 50 percent | Chance of at least 3 inches: 35 percent | Chance of at least 6 inches: 25 percent

New York: Chances for significant snowfall in the Big Apple are ticking up as models come into alignment on this storm. However, the heaviest amounts may still occur to the northeast and it will take a few more days for the forecast to come into focus.

Snow could begin early Saturday and continue for a good part of the day while winds crank up. There’s a chance the storm could miss to the east or come far enough west to draw in enough mild air for snow to change to rain.

Chance of at least 1 inch: 65 percent | Chance of at least 3 inches: 50 percent | Chance of at least 6 inches: 35 percent

Providence-Boston-Portland: This has the potential to be a very significant snowstorm in eastern New England. However, if the storm comes too close to the coast, snow could switch to sleet and rain, and there’s also the chance it passes far enough east for just a glancing blow.

Precipitation would probably begin early Saturday morning and end Saturday night. If the storm reaches its full potential, winds could become very intense, gusting over 50 mph, with blizzard conditions.

Chance of at least 1 inch: 75 percent | Chance of at least 3 inches: 60 percent | Chance of at least 6 inches: 50 percent

The above percentages (for the various population centers) may be conservative (compared to model projections) but take into account that the storm is still several days from forming.

Interior Northeast and New England: Depending on the track of the storm, locations west of Interstate 95 could also get walloped through western Connecticut, Massachusetts, Vermont, New Hampshire and much of inland Maine. A more offshore course might mean snow totals drop off quickly west of I-95, whereas a track closer to the coast would mean the potential for very heavy snow and strong winds for places like the Hudson Valley, Catskills, Berkshires and even the Green and White mountains.

As this storm is still four to five days away from developing, significant changes to the forecast are possible. But this has the potential to be a high-impact event for many people in the Northeast.