A multiday severe weather event is forecast to shift eastward across the United States on Tuesday, placing over 116 million people in a threat zone for severe storms. The storms carry the risk of tornadoes, damaging winds, and large hail, accompanied by heavy rain that increases the likelihood of widespread flash flooding.
The severe weather threat has been elevated to Level 3 out of 5 for 35 million people, with an additional 50 million under a Level 2 threat. The initial wave of storms began developing Tuesday morning, affecting areas from eastern Virginia up through the Tri-State area and into southern New England. These early storms are expected to produce gusty winds and torrential downpours, with a possibility of impacting the morning commute through flash flooding, particularly in urban areas.
"Significant flash flooding is also on the table, and we could be looking at more scenes of underwater roads and flooded subways," the FOX Forecast Center stated.
Main Storm System
The primary line of thunderstorms is expected to intensify throughout Tuesday afternoon as it moves east along a trough ahead of a cold front. The system is projected to reach the I-95 corridor during or shortly after the evening rush hour. Damaging winds capable of downing trees are anticipated to be the main threat, with a few tornadoes also possible. The FOX Forecast Center indicated that western New York and eastern Pennsylvania have the highest confidence for tornado development. Hail is also expected in this region and extending back toward the middle Ohio Valley, while the Mid-Atlantic states face the greatest risk of widespread, high-impact damaging winds.
Flash Flooding Concerns
The potential for flash flooding is a significant concern, with Tuesday's weather pattern described as remarkably similar to the event that caused substantial flooding across New York City, New Jersey, and western Pennsylvania the previous Saturday. Atmospheric moisture is expected to support rainfall rates as high as 2.5 inches per hour, which is nearly half the monthly average for July. This intensity, falling on ground already saturated from prior rainfall, heightens the risk of widespread flooding.
The main storm system is predicted to move through the I-95 Megalopolis between 6 p.m. and 8 p.m. before moving offshore by midnight. Torrential rain is also anticipated along the I-95 corridor, extending from the Delmarva Peninsula into southern New England.
The multiday severe weather event began on Monday, impacting the Upper Midwest with tornado-warned storms, large hail, and damaging winds. Iowa reported wind gusts of 80 mph, and Michigan experienced 3-inch hail.