A vigorously powerful cyclone will impact the Northeast on Wednesday night into Thursday, bringing a burst of damaging winds, heavy rainfall, and perhaps setting all-time minimum air pressure records for the month of October in eastern New England. The lower the pressure, generally the stronger the storm.
The storm, currently slated to develop Wednesday afternoon off the Delmarva Peninsula, will rapidly intensify Wednesday evening, its explosive strengthening bringing a significant windstorm to coastal New England.
In Maine, Rain rain is expected to develop between 9 p.m. Wednesday and midnight, according to WGME’s forecasts. The heaviest rain should end Thursday morning but some showers could linger through the afternoon. One to 3 inches of rain is expected.
Higher elevations may change over to wet snow Thursday morning, but snow does not look to be a major impact, according to WGME.
WGME graphic
Frequent northeast gusts of 40 to 50 mph are possible 4 a.m. to 9 a.m. Thursday. Peak gusts at the coast have a shot at getting over 50 mph, according to WGME.
A High Wind Watch in effect from Wednesday night through Thursday morning for the Maine and New Hampshire coast. Damaging winds could knock down trees and power lines.
Across all of Eastern New England, sporadic power outages and tree damage can be expected. This is especially true due to the presence of fully-leafed trees, which will more efficiently catch the wind like a sail and, in some places, sway or topple.
The coastal storm will begin to take shape during the mid-afternoon hours Wednesday, with rain and breezy winds along the coast from Maryland to northern New Jersey and the Big Apple. Things will really get going around sunset, especially for Long Island and the southern New England coast, where winds may gust above 40 mph.
Rainfall forecasts for New York City and adjacent suburbs are challenging, given they will see the system’s wraparound rain shield, but lesser in the way of strong winds and dynamics to the east. The National Weather Service is calling for a broad shot of 1 to 2 inches from the Tri-State area up to the Hudson Valley and Catskills, though there are reasons to believe that totals ultimately realized may tend to be less. A few snowflakes could mix in in the Adirondacks.
The bulk of the high impact weather will instead target New England overnight. For Connecticut, Rhode Island, and Massachusetts, the worst conditions are expected from about 10 p.m. Wednesday through 5 a.m. Thursday.
A strong low level jet or wind maximum will be racing just overhead, with 80 to 85 mph winds soaring just a couple thousand feet above the surface. It’s a challenge to gauge exactly how much of that momentum will “mix down” to the surface. There are indications that rapid changes of air pressure , heavy rainfall, and isolated downpour/thunderstorm structures may enhance the odds of some of that strong wind making it down to ground level.
This will likely be a widespread and impactful windstorm for hundreds of thousands of New England residents.
Expect building winds, especially east of Interstate 84 and south of the Mass Pike, around nightfall. As the low level jet sweeps overhead around midnight, wind gusts could top 55 to 60 mph in coastal Rhode Island, Narraganset Bay, Buzzards Bay, Rhode Island, and Southeastern Massachusetts. Because these winds are southerly and southeasterly, the entirety of the eastern New England coastline — from the Outer Cape to Downeast Maine — will be exposed to very high winds “off the deck.” In other words, as the low-level jet works its way up the coast, there’s nothing over the open water to slow the ferocious gales it brings to the coast.
There are some signs that point to the winds from this storm being even stronger than currently forecast. It’s not out of the question that a few gusts to hurricane force may sneak into the mix tonight in far eastern New England, although the chance of that happening in any one given location is relatively slim.
Farther west, 40 to 55 mph gusts are possible inland for the Boston to Providence corridor, with the Blackstone Valley to the Connecticut River Valley seeing 45 gusts. A bit of terrain influence may bring a few gusts to 50 mph in the Worcester Hills. Winds will taper off as one approaches the Berkshires, and noticeably west of there.
For rainfall, two bullseye zones appear favored: one east of Interstate 91, and the other in the 495 belt of Metrowest. More than 2 inches is forecast there, with even some isolated 3 to 4 inch totals possible. In between, around an inch and a half appears to be in the offing.
Amounts may drop some over Southeastern Massachusetts, where folks may spend more time in the rain-free “dry slot” than the system’s wraparound moisture.
The system will lash Maine with about an inch of rain early Thursday morning, bringing a 60 mph wind gust threat to the coast.
The ingredients that will spin up the storm were already coming together Wednesday morning. A batch of heavy rainfall was splayed from the nation’s capital southwestward to the Appalachians, soon to shift off the Mid-Atlantic coastline. Meanwhile, an invigorating shot of mid-level energy over the Great Lakes was barreling eastward, set to trigger the growth of a low pressure zone east of the Chesapeake Bay.
This low will rapidly develop, it central air pressure dropping at a rate sufficient to make it a “bomb cyclone,” wrote the National Weather Service in Boston. In order to classify for that tier, a cyclone’s core surface pressure must drop by 24 millibars in 24 hours; this one will do it by at least 30. The greater the difference in pressure over a certain area, the stronger the winds. It’s akin to damming a river; the greater the height that the water falls from one side of the dam to the other, the more intensely the water wants to rush across the dam to “balance out.”
As a result, the system may be an overachiever in terms of both wind and rainfall.
Light showers and some cloudiness will linger across much of southern and central New England Thursday before the region clears southwest to northeast during the afternoon. Behind the powerful front associated with the storm, breezy winds gusting 35 to 40 mph can be expected during the day from Washington D.C., Philadelphia, and Baltimore all the way up through the Canadian border.
Cooler, drier air in the storm’s wake will set us up for a picture-perfect weekend.
First big Nor'easter of the season. Impressive how quickly the storm is expected to strengthen tomorrow night through Thursday morning. pic.twitter.com/hXSQAsirEY
— Charlie Lopresti (@CharlieWGME) October 15, 2019
Comments are not available on this story.
Send questions/comments to the editors.
