Temperatures Friday soared into the upper 70s to near 80 in many Mid-Atlantic and Northeast cities. Fast forward to early next week, and forecasters may be tracking nearby snow. Far enough inland, it may even require some plowing.
A sneaky system looks to spin up south of New York City early Monday, working with just enough cold air to toss some borderline snow back toward the coast. Precipitation that falls inland is likely to be snow, possibly stacking up several inches high where temperatures cooperate. In the big cities from Washington to Boston, a rain-snow mix or mostly rain is favored.
At four days away, there’s still plenty up in the air that needs to be nailed down before timing and amounts can be offered. But with several ingredients already in motion, we can discuss the setup and possibilities that will have an effect on how things shape up to start next week.
After a pleasant Friday, a cold front will sweep through the Northeast overnight, with comparatively chilly air arriving for Saturday. Highs will be 25 degrees or more cooler than they were Friday, with upper 40s or lower 50s likely in Hartford, Conn., New York, Philadelphia, Baltimore and Washington. Boston could remain in the mid-40s.
The coolest weather is expected Sunday, ahead of the storm, with freezing low temperatures in the morning and highs only in the 40s throughout the Mid-Atlantic and Northeast. As the storm begins to develop, temperatures Sunday night will fall into the upper 20s in Boston, lower to mid-30s in Philadelphia and New York City, and closer to 40 in Washington. Farther inland away from the coast, a more uninterrupted supply of cold air will hang in place Sunday night into Monday morning — around the same time precipitation is slated to begin.
Light precipitation will fall beginning before sunrise Monday in the Mid-Atlantic, but there it’s likely to be rain, except possibly mixing with a bit of sleet or snow at the onset, mainly well north and west of Interstate 95. If the storm arrives early enough farther north, before the cold retreats, a few snowflakes could fall in New York City and Hartford around the start of the workday.
The storm will be carrying with it a slightly milder air mass, which will keep most precipitation near the coast, and in the big cities, as rain. The only shot of a few snowflakes or a little sleet is at the onset.
Dry air in place could erode some of the initial precipitation, but rain should commence in the Boston to Providence corridor between lunchtime and midafternoon Monday.
By evening, rain will be winding down in Washington and Philadelphia, with a few additional hours likely in New York City and the Northeast.
There is a chance of a few snowflakes on the backside for the tri-state area if cold air wraps into the departing system quickly enough. No accumulation would be expected there.
There are some models, like the European model, that bring the storm slightly farther north — meaning more moisture, or slightly more snow, for inland areas.
Overall, however, the models are all largely in line with one another.
The National Weather Service in Albany summed it up well, writing, “the bottom line is that a winter weather event certainly appears to be possible Monday into Monday night, and good model agreement is resulting in more certainty than we often see with a 4-day forecast.”
Limiting factors for snow
What will make it tough to get snow along the Interstate 95 corridor is the “angle of attack,” so to speak, of the upcoming system. Because the low-pressure center will drift south of Long Island, winds will initially be southeasterly. That’s a warm wind off the comparatively milder waters, which will erode any chances for snow, let alone accumulation, at the coast.
Moreover, the high-pressure system exiting to the northeast is in the wrong position for a big snowstorm. For that, we’d need a “blocking high” — or high pressure that sits and forces a low-pressure system to stall over the Northeast, while at the same time feeding cold air south.
Because the high is exiting more to the east-northeast and not the north or north-northeast, winds from the southeast will draw in slightly warmer marine air, rather than colder or continental air.
Time of day will play a role, with the higher March sun angle more efficiently heating the ground even through clouds.
“The timing of the [precipitation] will have an impact on accumulation, as it can be difficult to accumulate snow during the daylight hours in late March, especially on road surfaces,” wrote the National Weather Service in State College, Pa.
Who will see snow?
If you’re looking for snow, you have two options: inland, or up. In other words, unless you live far inland, where temperatures will already be cold, you’ll need at least 1,000 feet of elevation to help you out.
This could be the case in northwestern Connecticut, western and central Massachusetts in the Berkshires and Worcester Hills, and much of New York state. There will also be some lake-effect enhancement off Lake Ontario, which could dump several additional inches across the Tug Hill Plateau.
Interior Vermont and New Hampshire might also see some snow, but they could also be too far north to pick up meaningful precipitation.
The best chance of accumulating snowfall looks to be across northeastern Pennsylvania, New York state away from New York City, northern/western Connecticut and Massachusetts, and perhaps extreme northwestern Rhode Island. Southern Vermont and New Hampshire could see a few flakes.
It is worth noting that warm ground temperatures mean some of the snow is likely to melt upon contact, so it might not stack up quite so high.
Meanwhile, mild temperatures Tuesday will melt whatever does fall. This looks to be a short-lived winter weather event, typical of late March, with a return to more springlike temperatures next week.