Next week, the Southeast is under a heat dome that will bring several rounds of severe storms and flooding to the Northeast and Great Lakes.
Fall is just around the corner, but it won’t feel like it in many parts of the southern and central United States, where a heat dome stretching from the Rocky Mountains to the East Coast has caused temperatures to exceed 100 degrees over the past week, especially in Texas, Oklahoma, Kansas, Louisiana, and Arkansas. Combined with the humidity, some days it felt close to 110 degrees.
Although the heat itself may not reach many record highs over the next few days, nighttime lows are expected to be 10 to 15 degrees Celsius above normal, with some locations expected to reach over 20 degrees Celsius. More than 100 new record daily lows are possible over the next week.
But a heat dome is an area of high pressure that traps warm air beneath it, which does more than just raise the temperature. It also presents a two-pronged storm threat facing the Northeast and Great Lakes starting Tuesday.
First, they act like rocks in the jet stream, disrupting the normal flow of air and lifting the storm onto its edges. This is similar to the situation that caused deadly flooding across the Plains and Midwest earlier this month.
It also sharpens the temperature contrast between the trapped hot air and the cold air to the north and east. This contrast creates an atmospheric rotation that developing storms can use to organize and strengthen.
The first threat of heavy rain begins Sunday afternoon and continues overnight into Monday, with the heaviest rain moving through Pennsylvania and New York into New Jersey and New York City overnight.
Rain had already begun to fall across the Midwest from Chicago to Detroit on Sunday morning, and could start moving east around 6 p.m., reaching New York City by 10 or 11 p.m. A corridor stretching from the Great Lakes to southern New England could see 2 to 3 inches of rain, but there is low confidence how far east the rain will travel.
Additional rain and flooding is possible across the Northeast Tuesday into Thursday, but there is low confidence in exactly where those storms will form.
As the Earth heats up due to climate change, our warm atmosphere can hold more water and fuel, causing heavy rain to occur more frequently.
