Watching the next storm…still far away, but worth mentioning

Good evening.

It has been a slow winter for the most part, with snow largely lacking for most areas. There was a strong low pressure system that moved through the region this weekend, but without a cold air source, most of the precipitation fell as liquid. Most models seem to agree that late this week into the following weekend, another strong storm system should develop off the southeast US coast and track up off the east coast. The key question marks are, how strong will it be and what kind of cold air can penetrate to produce a snow event? Remember, at this time last winter, even New England had yet to see any significant snow – the blockbuster snow was still to come.

Disclaimer: it is still very early – the event is 5 to 7 days away, and although that is not in “fantasyland”, there is still considerable variance possible. Slight track or intensity changes can mess the whole forecast up.

GFS model forecast for Saturday morning (from 18Z January 17). Notice the large snow area along the I-95 corridor.

GFS model forecast for Saturday morning (from 18Z January 17). Notice the large snow area along the I-95 corridor.

The most recent GFS models show a snow lovers’ dream for practically the entire east coast, except for interior areas, as a low rapidly intensifies to about 977 mb off the coast. Only a few headland areas, especially Nantucket, would change to rain for a while, since the cold air would penetrate well south thanks to a ridge far to the north. Strong winds to tropical storm force would likely lead to blizzard conditions for some areas as well. This would be a crippling storm for the Northeast corridor if that model verifies.

ECMWF model run for Saturday morning (from 12Z January 17). This is a forecaster's nightmare...

ECMWF model run for Saturday morning (from 12Z January 17). This is a forecaster’s nightmare…

The ECMWF model prefers a solution farther north and northwest crossing the 40/70 benchmark. This would be more likely liquid for the southern mid-Atlantic, with snow for most of New England and a clear boundary around the Cape Cod Canal and along Long Island. Precipitation type would be a challenge in this scenario, as the cold air may also be lacking.

CMC model run for Saturday afternoon (from 12Z January 17). Rain on the coast, snow inland.

CMC model run for Saturday afternoon (from 12Z January 17). Rain on the coast, snow inland.

Finally, the CMC model (the least reliable of these) also shows a tricky forecast with a P-type line right along the I-95 corridor. In this case, rain would predominate along the coast with VERY heavy snow inland. The boundary will be difficult to draw but make a world of difference. Once again, winds would likely be very strong.

GFS ensemble members' low positions for Saturday morning (from 18Z January 17). Notice there is so much uncertainty.

GFS ensemble members’ low positions for Saturday morning (from 18Z January 17). Notice there is so much uncertainty.

When it comes to the ensembles, there is considerable spread among them as well. Some of them even take the storm so far south that it largely misses the region, keeping the activity well south. Others take the perfect track for snow along I-95, while still others are too warm and would be rain near the coast. There is still a lot of time to pin down the forecast, so stay tuned this week. A major storm with high impacts is certainly possible, but there are a wide range of solutions at this point.

Forecaster Craig Ceecee (@Ceecee_Wx)

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