Winter Storm Ultima Will Bring Snow to the Northeast as Spring Arrives (FORECAST)

Jon Erdman
Published: March 19,2015



 

Sick of snow? Well, Winter Storm Ultima will bring a snowy blanket to spring's official arrival (Friday 6:45 p.m. EDT).
(MORE: Worst Winter Cities 2014-2015 | What Is the Vernal Equinox?)
Winter weather advisories have been posted for over 32 million in the Northeast, including the Philadelphia and New York City metro areas.

Winter Alerts

Current Radar

The Setup

In the wake of yet another snowmaker for eastern Maine and parts of Atlantic Canada, fresh cold air has been dragged into the Northeast.
(FORECAST: The Cold Returns)
Disturbances in the northern (polar) and southern (subtropical) jet streams and associated moisture will swing into the Northeast beginning Thursday night.
In response, an area of low pressure will spin up off the Northeast seaboard Friday and Friday night. A reinforcing arctic cold front will then sweep into the Northeast Saturday.
Before you become concerned that this sounds like a crippling Northeast snowstorm the likes of which we saw in January and February, there are several aspects that mitigate this threat:
- The cold air becomes a little "stale" Friday, thus near-surface temperatures may allow for some melting of falling snow.
- It's also late March. With the sun higher in the sky, that would also add several degrees of warmth to an air mass compared to what we would see in January or February.
- The offshore low-pressure system isn't expected to become strong. Therefore, strong winds will not be an issue.
- The reinforcing arctic cold front most likely won't arrive to combine with the offshore low until Saturday night, when the low will be moving into Atlantic Canada. This will limit the potential for heavy precipitation - for example, over one-foot snow totals - over the northeastern U.S.

Friday's Forecast

Saturday's Forecast

Snowfall Forecast

Ultima Forecast Timing

• Overnight: Wet snow from the Appalachians of West Virginia and piedmont of western Virginia north into central Pennsylvania. Snow or rain possible into the Washington, D.C. and Baltimore metro areas overnight. Otherwise, a steady rain will fall in lower elevations south of the D.C. metro and over lower elevations of West Virginia.
• Friday: Wet snow spreads from central/eastern Pennsylvania and southern New York to southern New England. Slush buildup on roads is possible for the morning and afternoon commutes, particularly in the Philadelphia and New York City metro areas. Snow may fall at the rate of an inch per hour, for a short time.
• Friday night: Wet snow continues from southern New England westward to northeast Pennsylvania, including the New York City metro. A little snow is also possible in parts of western, central and Upstate New York after midnight.
• Saturday: Expect additional snowfall over eastern New England as an area of low pressure passes by just offshore. Meanwhile, another area of snow will occur over central/Upstate New York and northern New England as an arctic cold front approaches.
• Saturday night: Snow in Maine, northern New Hampshire and northern Vermont tapers off after midnight. Snow will have ended elsewhere.

Ultima Forecast Snow Totals

• Highest accumulation: A swath from south-central Pennsylvania, western Maryland and the eastern West Virginia panhandle to northern New Jersey and Long Island will likely see the highest accumulations, with over 5 inches of snow possible. Given somewhat marginal temperatures, some falling snow may melt on pavement, so higher accumulations may occur on grass than roads. 
• Lighter accumulation: New England, central/Upstate New York, I-95 corridor south of Philadelphia should see accumulations of mainly 3 inches or less. Again, some snowfall may initially melt on roads Friday in the Mid-Atlantic states. Parts of far northern New England (Maine, northern New Hampshire, northern Vermont) may see over 3 inches of snow Saturday.

(FORECASTS: Boston | NYC | Philly | Baltimore | Washington)

Average date of last measurable snow of the season, snow that typically falls after March 20, and the percent of the season's snow that falls after March 20.

Perspective: The Last Snow of the Season

If you're truly sick of snow, you're probably wondering when the last snow of the season occurs.
While every season is different, the season's last accumulating snow typically falls from late February as far south as the Nation's Capital, to late March in southern New England, to April in Maine.
In snow-weary Boston, it's par for the course to pick up another 3 to 4 inches of snow after March 20. Bangor, Maine can expect another 7 to 8 inches of spring snow, comprising roughly one-eighth their season's average snowfall.
Last spring, 0.3 inch of snow fell in Boston on April 16. Boston's previous record snow season featured an April 7-10, 1996 dumping of 7.3 inches of snow.
Of course, we'd be remiss not mentioning the April Fools' Blizzard of 1997, when 25.4 inches of snow in just 24 hours paralyzed Boston and parts of southern New England.
Check back with us at weather.com and The Weather Channel for updates to this forecast.

MORE: Boston's Snow Misery 2015