Severe Thunderstorms Expected to Impact Eastern United States
Millions of people in the eastern United States are bracing for a serious and widespread outbreak of severe thunderstorms. The storms, expected to affect more than 50 million people from Georgia to New York, could bring destructive winds, hail, and even a few tornadoes. The National Weather Service Storm Prediction Center has declared a Level 4 out of 5 risk of severe storms in parts of the Mid-Atlantic region, indicating the potential for a high-impact event.
The areas at greatest risk include Washington, Baltimore, Roanoke, and much of the Appalachians toward the Cumberland Plateau of Tennessee. The National Weather Service is warning of a severe weather outbreak with widespread damaging winds, locally destructive, and isolated tornadoes. This is the first time Washington has been included in this tier of risk since June 2013.
A Level 3 out of 5 “enhanced” risk covers the zone from Atlanta to just west of New York City, where damaging winds and a few tornadoes are still possible but may not reach the intensity of the Mid-Atlantic. The storms are most likely to occur along the Interstate 81 corridor in the mid-to-late afternoon, moving towards the Interstate 95 corridor early in the evening and the Atlantic coast by sunset.
Tornado or severe thunderstorm watches are expected to be issued early Monday afternoon ahead of the storms, with more targeted warnings issued when storms are imminent or occurring. The storm system has already brought tornadoes to central Illinois on Sunday and a couple tornadoes formed in Iowa on Saturday.
The primary hazard from these storms will be damaging to destructive straight-line winds. The National Weather Service warns that gusts of up to 80 mph are possible in the strongest storms. The storms will tap into a potent jet stream overhead, resulting in violent downbursts. Additionally, a layer of dry, dense air at mid-levels may mix into thunderstorm downdrafts, causing pockets of rain-cooled air to become heavier and accelerate towards the ground with even stronger winds.
Tornadoes are possible with any of Monday’s storms, with the greatest risk in the Mid-Atlantic region, including the central Appalachians through Northern Virginia and central Pennsylvania. Initial storm cells in certain areas may be rotating supercells, presenting the risk of hail, straight-line winds, and tornadoes. Eventually, the storms are expected to merge into a fierce line known as a “QLCS” or a quasi-linear convective system, featuring widespread straight-line winds with embedded rotation.
While hail would be limited to initial discrete cells, the strongest storms may contain hail ranging from penny to nickel-sized. Progressive movement of the storms is expected to lessen the flood risk, but torrential downpours could still cause brief flooding, particularly in areas with poor drainage.
Residents are advised to prepare by charging devices and batteries ahead of possible power outages, securing or moving loose outdoor items, avoiding parking vehicles near large trees, seeking shelter in an interior room away from windows in the event of a tornado warning or destructive wind warning, and planning to be off the roads by the time severe weather commences.
Stay informed and be prepared for severe weather conditions by having a way to be notified if warnings are issued for your location.