EF2 tornado in Mercer County, New Jersey

The tornado which began in New Hope, Pennsylvania crossed the Delaware

River and entered Mercer County, New Jersey, in the area of

Washington Crossing. Multiple reports of residential tree damage

were received from Washington Crossing, and the survey team

observed tree damage along River Rd on the New Jersey side of the

Delaware River. From there the tornado continued southeast and

crossed Pleasant Valley Rd. The first indications of EF2 damage

came on that road, with numerous large hardwood and softwood trees

snapped, sheared, and/or uprooted. The tornado continued

southeastward and crossed through Baldpate Mountain. Continued

heavy tree damage was observed in this area. An access road to the

top of the mountain was barely passable when the survey team

reached it in late afternoon, after many hours of tree clearing

work by local parks officials and private companies. Hundreds of

trees were snapped or damaged on this mountain. Damage continued

down the mountain through Fiddlers Creek Rd and Church Rd. The

tornado path then crossed Washington Crossing State Park. Further

damage was observed just southeast along Bear Tavern Rd. In fact,

some of the largest downed trees were observed in this area.

However, by this point damage became increasingly unidirectional

as the storm's rear flank downdraft likely wrapped around the

tornadic circulation. Sufficient evidence of tornadic winds still

existed in the Bear Tavern Rd area, but it is estimated the

tornado lifted soon after, shortly before entering much more

densely populated areas near the Trenton Mercer Airport.

A strong shortwave trough moved east-southeastward out of the Great Lakes region on July 29. An associated, strengthening surface low also tracked out of the Great Lakes and into upstate New York. A warm front associated with this low moved through most of New Jersey and eastern Pennsylvania during the late morning and early afternoon hours. This front, combined with the remains of widespread convection to the west from the previous overnight and morning hours, brought significant cloud cover to the eastern mid-Atlantic for much of the day on the 29th. This was mainly in the form of mid and high level cloud cover, however, and temperatures still warmed to near seasonal levels behind the warm front, allowing moderate to strong instability to build. Meanwhile, the robust surface and upper level disturbances approaching the region brought both strong forcing and unseasonably strong wind shear. By mid-afternoon, an unusually favorable convective environment existed over eastern Pennsylvania and New Jersey.

The result of this environment was a rare tornado outbreak across the area. Initially, during the mid-afternoon hours, mixed convective modes over east-central Pennsylvania produced a couple instances of damaging wind and brief tornadoes as storms attempted to overcome cloud cover and some light stratiform rain in the area. With time, as storms moved into better instability and a less contaminated environment over far eastern Pennsylvania and New Jersey, they took on more supercellular structures. Multiple cyclic supercells would go on to produce several tornadoes, three of them strong (EF2+) over eastern Pennsylvania and New Jersey. Convection persisted past the sunset hour with little to no loss in intensity due to the strong forcing. The only thing that put an end to the outbreak was the coastline, as storms moved offshore towards 9 to 10PM local time. Even offshore, one supercell continued to exhibit strong rotation and likely produced a strong waterspout for tens of miles over the Atlantic.

Fortunately, and miraculously, no serious injuries or loss of life occurred as a result of this outbreak. With the passage of a cold front late on the evening of the 29th, cooler, drier, and much less active weather would grace the region for several days as clean-up efforts began.