The threat of tornadoes will be trending up tonight across portions of the Mid Atlantic, according to the National Weather Service’s Storm Prediction Center (SPC). Specifically, central and southern New Jersey, most of Delaware, southeastern Pennsylvania including Philadelphia, eastern Maryland including Baltimore, northeastern Virginia, and the Washington DC metro region have the highest risk level of tornadic thunderstorms later today.
According to the latest Convective Outlook issued by the SPC, forecast model solutions continue to indicate that low-level winds will intensify after dark over parts of eastern Pennsylvania and surrounding areas as a shortwave trough rotates into the area. “Favorable low-level shear profiles suggest some risk of rotating cells and tornado or two, although weak lapse rates and time-of-day will be unfavorable for robust updrafts,” wrote the SPC.
Unfortunately, this means the best chance of tornadic thunderstorms will be during the overnight hours and nocturnal tornadoes can be lethal. According to the National Weather Service, severe weather that occurs overnight can increase personal vulnerability and have significant potential impact on the public. This is due to the public being less likely to receive warnings overnight as many people are asleep, tornadoes are much more difficult to spot at night, and more people who are inside vulnerable housing and building structures such as mobile homes are there at day rather than night. The National Weather Service warns that nighttime tornadoes are more likely to cause fatalities than daytime tornadoes.
At this time, it appears the greatest threat of tornadic thunderstorms is between 8 pm and 3 am.
There is a risk of nocturnal tornadoes tonight in portions of New Jersey, Delaware, & Pennsylvania. DON’T BE THAT DUCK!
— the Weatherboy (@theWeatherboy) August 14, 2023
Beyond the threat of tornadoes, severe thunderstorms can also produce large hail, damaging wind gusts, and even heavy rain. Some thunderstorms may dump copious amounts of rain and move slowly, creating isolated flash flood concerns too. The National Weather Service advises, “Turn around, don’t drown; never drive through flood waters.”
The threat of tornadic storms and severe thunderstorms with heavy rain will linger in portions of southern New England and the southern Delmarva region into Tuesday morning and afternoon while fading away elsewhere.