The system is located within a major dip in the jet stream, the same one that powered the deadly storm in the Pacific Northwest, and is adding wind energy and momentum to the upper atmosphere. That’s why parts of the South could face damaging winds and an isolated tornado risk on Saturday, while the same jet stream energy could fuel powerful gusts in New England on Sunday night.
The storm is also fueled by strong temperature contrasts. Ahead, temperatures will be 20 to 25 degrees above average, while falling to below average levels in their wake. Even New York City and Boston could see highs in the 60s on Sunday before the system’s strong cold front passes, accompanied by showers and perhaps thunderstorms.
On the cold tail of the storm, accumulating snow could cover Appalachia from Sunday night into Monday.
Drawing abundant moisture from the Gulf of Mexico, it will generate heavy rain from Mississippi to Maine over the weekend, producing totals of 1 to 3 inches. Nashville, Raleigh, Richmond, Washington, Philadelphia, New York and Boston should expect moderate to heavy rainfall.
Flight disruptions are possible due to heavy rain and the system’s wide area of strong winds, particularly late Sunday into early Monday in the Northeast.
It looks like a calmer weather pattern will develop towards the middle of next week.
The drop in the jet stream will encourage the development of a low pressure system over areas of Oklahoma and Texas on Thursday. That low will extend northeast toward the Great Lakes, pushing a cold front eastward. That front will bring severe weather to the South and serve as a focus for heavy rain in the Ohio and Tennessee Valleys, the Mid-Atlantic, and the Northeast.
On the cold side of the system, a corridor of snow may fall over the central and northern Appalachians, particularly in Pennsylvania and New York state.
That main low pressure system will slide toward Quebec, but a secondary band of low pressure will likely form along its cold front. That will drag the energy of the jet stream toward the New England coast, increasing the likelihood of strong winds hitting the coast. Onshore flow could also cause a small storm surge (or a rise of ocean water above normally dry land) and minor coastal flooding.
Strong winds in the Rocky Mountains on Thursday
Wind advisories and high wind watches and warnings extend from near Taos, New Mexico, north to Colorado and Wyoming, as well as the Nebraska Panhandle.
As the jet stream oscillates through the area, high terrain will be found pushing some of the strong momentum aloft. Mountain gusts of 60 to 70 mph are possible, with gusts of 50 to 60 mph in the lower elevations of southeastern Wyoming and northwest Nebraska.
The strongest winds will occur through Thursday night.
Strong storms in the south on Friday and Saturday
On Friday, the Storm Prediction Center described a level 1 of 5 marginal risk of severe weather. It extends from northeast of Dallas to near Little Rock.
The initial storms that form Friday night are expected to be “lifted,” or rooted in warm air a few thousand feet above a shallow bank of cooler air near the surface. That will limit damaging wind and tornado risk, meaning small hail would be the main concern.
By Saturday, increasing southerly winds ahead of the cold front will drag a filament of heat and humidity over the Mid-South. A Level 2 of 5 severe weather risk extends approximately from Houston to Memphis. The primary concern is the formation of a squall line with scattered strong or locally damaging winds and some embedded tornado circulations.
At least some low-level severe storm potential may persist in the Carolinas and/or Virginia Tidewater on Sunday as the cold front pushes eastward.
Strong winds in the northeast on Sunday night
On Sunday night, a fast-moving jet stream, with winds of 80 to 100 mph just a half mile above the ground, will cut across southern New England.
Some of that momentum can move to the surface. Gusts of 35 to 50 mph will be common along and east of Interstate 95 north of the Mason-Dixon line, with gusts of 60 mph on the coast from the Delmarva Peninsula to Long Island and eastern New England. Some computer models simulate the potential for even stronger winds, especially in far eastern Massachusetts and southeastern Maine.
Isolated or scattered power outages are possible where the strongest gusts occur.
Heavy rain and snow over the weekend
On the warm side of the system, which will be east of the system’s track, a burst of rain will fall 1 to 3 inches. Heavy rain will first reach the Ohio and Tennessee Valleys on Saturday night, move into the interior of the Mid-Atlantic and Northeast on Sunday, and move closer to the coast Sunday night into early Monday.
Anyone east of the Appalachians will see rain instead of snow as southerly winds bring in unusually mild air. To the west, moisture will swirl toward the cold side of the system. That will likely result in a swath of snow from the West Virginia Appalachians to upstate New York and northern Vermont. The exact location of the snow, nor totals, can be determined yet, but some people could end up with 6 to 8 inches, especially at higher elevations.
Much of this snow would fall Sunday night into Monday, after a period of rain.
Jason Samenow contributed to this report.