Thunderstorm Wind in Cape May County, New Jersey

Wires were downed on US-9 in both directions.

A highly anomalous weather system affected much of the eastern United States on April 13. From the night of April 12 through the day on April 13, strengthening low pressure tracked in an almost due northerly direction from the Ohio Valley, through the Great Lakes, and into Canada. A record strong low level jet developed ahead of it along the East Coast. In the mid-Atlantic, a warm front moved through the region during the morning of the 13th, bringing showery weather. During and after the warm frontal passage, mixing with the low level jet brought destructive wind gusts to the surface, especially near the coast where gusts were enhanced by a well-defined gravity wave.

During the afternoon hours, a strong cold front approached, providing strong forcing to an environment of strong to extreme wind shear. Instability was limited due to a lack of clearing following the morning warm frontal passage. However, enough heating occurred by mid-afternoon that a line of strong to severe thunderstorms did manage to develop, producing a number of damaging wind reports as it moved towards the coast.