Odds of a New England blizzard this weekend are increasing
A high-impact, powerful winter storm is becoming more likely to affect parts of New England and potentially the Mid-Atlantic states this weekend.
Threat level: The storm, now simulated by most of the reliable computer models used as weather forecasting tools, could bring upwards of a foot of snow, blizzard conditions due to high winds and heavy snow and coastal flooding from Long Island to Maine.
The big picture: How strong the storm becomes and where it tracks depends on a complex interaction between disturbances in two branches of the jet stream — the corridor of fast-flowing winds at about 30,000 feet, which helps steer and energize weather systems.
- A disturbance across the Southwest on Wednesday and Thursday is projected to link up with energy in the northern or polar jet stream Thursday night and into Friday, carving out a large southward dip or trough in the jet stream and forming an area of low pressure at the surface.
- This low may start out humbly, spreading light rain and snow from the Carolinas to the Mid-Atlantic Friday into Friday night, but as it moves north-northeast, it could undergo rapid intensification, becoming a bomb cyclone swirling somewhere near Cape Cod by Saturday.
- This would put it in a classic position for a nor'easter, a storm named for its gale to storm-force winds blowing from the northeast to southwest. Such storms can often produce high waves and storm surge flooding that erode coastal areas and can flood low-lying areas in Boston, for example.
- The National Weather Service forecast office in Boston warned of the coastal flood risk in a forecast discussion Tuesday, stating: "Astronomical tides will be high on Saturday. Strong winds driving the water toward shore will bring surges that could cause coastal flooding along vulnerable sections of the east and south coasts."
Details: Since the storm is a few days away, it is too early to make specific snowfall predictions, but computer model guidance has been consistent enough to sketch out the contours of the forecast.
- Areas to the north and east of Philadelphia will have the greatest chances of seeing significant amounts of snow.
- Southern New England, coastal New Hampshire and Maine look to be the most likely areas to see amounts on the order of 6-12 inches and higher.
- The exact track and intensity of the storm will determine where the heaviest snow falls, and could make the difference between a blizzard that stretches from New York City to Boston and one that mainly affects eastern New England.
- There is still the possibility that the storm will not move close enough to the coast and intensify sufficiently to produce heavy snow, high winds and coastal flooding. However, the no-storm scenarios have become less likely on Tuesday.
The intrigue: As the storm approaches New England, it will traverse record warm ocean waters for this time of year, which could help intensify the system and also may introduce some sleet or rain into the mix along coastal areas.
- The Gulf of Maine in particular is one of the fastest-warming ocean regions on Earth, a trend tied to climate change and other factors.
- Waters have also been getting milder south of New England, which can influence nor'easters and other storms.
What's next: After this storm moves through, the weather pattern may turn milder for the first part of February, particularly across the Midwest and East.