A major East Coast storm will rapidly organize Sunday and then explosively intensify Sunday night, unleashing heavy rain and strong winds in the Mid-Atlantic and Northeast.
The storm will draw tremendous moisture northward, as it absorbs Tropical Storm Philippe, which originated from the Caribbean. Rainfall totals from Northern Virginia to Maine should reach one to five inches, with the highest totals in the interior Northeast, where pockets of flooding are possible.
The storm’s rapid rate of intensification, meeting the criteria of a meteorological bomb, means winds will really start to crank by Sunday night.
Wind advisories blanket the northern Mid-Atlantic states, including the Washington and Baltimore regions, for wind gusts up to 40-50 mph Sunday night. Even higher winds are expected in the Northeast, where the National Weather Service has hoisted high wind warnings for gusts as high as 65 mph near the coast and 55 mph inland. These winds could cause power outages, with the risk increasing north of the Mid-Atlantic toward the New England coastline.
On the storm’s backside, snow is likely Sunday night in the high elevations of western Pennsylvania, Western Maryland as well as West Virginia. Above 3,000 and especially 4,000 feet, totals over six inches are possible.
Storm details for the Mid-Atlantic, focused on Washington and Baltimore
Through midafternoon Sunday, the Interstate 95 corridor through Washington and Baltimore, will sit in a dry slot — with just intermittent showers. Heavier rains will be positioned to the west and east.
By the late afternoon and into the evening, the rain will fill in over both metro regions and may become heavy at times.
The rain should taper off during the predawn hours. Models generally show 0.5 to 1.5 inches of rain falling close to Washington and Baltimore. Totals will tend to be highest in the northeast part of this region toward Baltimore, and the heavier totals may focus toward the mountains.
As the rain increases, so will winds. They won’t be particularly noticeable through the late afternoon but should crank up by 5 or 6 p.m., when the possibility of 30 mph gusts begins. The period of strongest gusts, in which occasional gusts of 40-50 mph are possible, is likely to be between 8 p.m. Sunday and 8 a.m. Monday. It isn’t out of the question that some areas, especially the mountains and spots along the Chesapeake Bay, may see gusts over 50 mph.
Because of the rain and foliage on trees, some downed trees and power outages cannot be ruled out.
The sun will be back out and winds will gradually relent on Monday, but it will be a very blustery day.
Storm details for New England
The storm will be most significant in coastal southern New England, though the entire Northeast will feel some impact.
Unlike a typical fall nor’easter, winds will sweep in from the southeast as the storm center tracks up the Hudson Valley. That puts the heaviest rainfall and strongest winds over areas to the east.
Winds will remain light across New England into Sunday afternoon but will pick up around suppertime and really crank by midnight along the south coasts of Connecticut, Rhode Island and Massachusetts. It will take until sunrise Monday for the worst conditions to overspread northern New England. Blustery winds of 30-40 mph will be quite common during the overnight period for everybody, but the strongest gusts are expected nearest to the coast.
Cape Cod, Cape Ann and Down East Maine will be closest to the storm’s low-level jet, a narrow zone of enhanced winds. Here, gusts of 65 mph are possible.
– Don’t bother raking this weekend
– Plan on power outages Sunday Night
– Downed Trees Likely pic.twitter.com/bKCd7oVdR9
— Eric Fisher (@ericfisher) October 28, 2017
Elsewhere, winds may very briefly top 55 mph along the Interstate 95 corridor and up to 50 mph east of Interstate 81. A secondary wind maximum will be found in the monadnocks, the White Mountains and the Champlain Valley because of the elevation helping “poke into” the windy skies aloft, where gusts to 55 mph are possible.
As the storm departs around noon Monday (and closer to Monday evening in northern regions), winds will abruptly switch around from the west, ushering in cooler air with 45-mph gusts. The wind will die down overnight Monday.
Heavy rain and localized flooding also are a threat. A widespread swath of one to two inches will sweep across most of New England, with lesser amounts in western New York. The terrain of the Southern Adirondacks, the Catskills and the Berkshires, meanwhile, may help to enhance rainfall, with upward of three inches falling in a few pockets. There is a low risk of an isolated thunderstorm or two. If any do occur, they could help to mix down stronger winds while also upping rain amounts.
Localized heavy rain could also target extreme eastern Massachusetts and Cape Cod, depending on whether showers and thunderstorms connected to tropical moisture and the remnants of Tropical Storm Philippe sweep over the area.
Coastal flooding is a minimal concern due to low astronomical tides, but minor beach erosion is possible, particularly along east-facing beaches.
Skies will clear from west to east on Monday afternoon as the storm exits into the Canadian Maritimes, leaving sunshine and seasonable conditions for trick-or-treaters Tuesday.