Tropical Storm Karen was a system that brought record-breaking rainfall and flooding to southeastern Pennsylvania and other Mid-Atlantic states in October 2013.

The remnants of Karen then turned eastward and crossed Florida, before evolving into a nor'easter off the coast of North Carolina, stalling off the Delmarva Peninsula through October 12.

[1] The system travelled south of Jamaica and the Cayman Islands through the end of September, producing disorganized showers and thunderstorms.

[5] Late on October 2, the disturbance began to quickly organize,[6] though a Hurricane Hunter reconnaissance aircraft did not find a well-defined circulation.

[7] Another Hurricane Hunter aircraft investigated the storm early on October 3, finding a closed circulation as well as surface winds of 60 mph (97 km/h) and a pressure of 1004 mbar (29.65 inHg).

However, the NHC anticipated Karen to gradually strengthen into a hurricane, citing a marginally favorable environment with continuous moderate wind shear as an inhibiting factor.

[9] The cloud pattern of Karen remained sheared throughout October 3, with the LLCC partially exposed west of the convective mass.

[10] Late that day, a Hurricane Hunter aircraft found that Karen had deepened to a pressure of 999 mbar (29.5 inHg).

[10] At 21:00 UTC on October 3, Karen peaked with winds of 65 mph (105 km/h) and a central minimum pressure of 998 mbar (29.5 inHg).

The main area of convection was located around 115 miles (185 km) away from the center, and only sporadic bursts of thunderstorm activity occurred over the LLCC.

[12] A NOAA reconnaissance jet found that wind shear west of the system was stronger than previously analyzed by weather models.

[15] At 00:00 UTC on October 6, Karen weakened into a tropical depression,[1][16] as shear from an eastward-moving deep-layer trough finished off the storm.

[1] Subsequently, the remnants of Karen turned eastward and interacted with a cold front on October 7, transitioning into an extratropical cyclone soon afterward.

Afterward, the system drifted southwestward back towards Florida for the next few days, closing off a long, clockwise loop in its track.

An experimental alert system was devised after the catastrophic impact of Hurricanes Ingrid and Manuel, being put to the test during Karen's passage.

PEMEX, an oil drilling company owned by the government, was alerted to Karen's strong winds and high waves.

In Quintana Roo, authorities ordered residents to remove trash from streets and to clear debris, in the event that the objects blocked sewers during a flood.

[20] In addition, citizens were encouraged by Comisión Nacional del Agua (Conagua), the Mexican National Weather Service, to exercise extreme precautions and to continue listening to civil protection calls.

Sea vessels were advised by the agency to exercise caution in waters near the north and coast of the Yucatán Peninsula, due to the high swells.

The tropical storm generated high waves and moderate to heavy rains in Yucatán and Quintana Roo, in addition to precipitation in Veracruz, Tabasco, and Campeche.

[21] Strong winds from Karen alleviated a red mite infestation in Tabasco and Campeche, carrying the parasite off crops.

[22] While the storm was threatening the Gulf Coast of the United States, the NHC issued several tropical cyclone warnings and watches as Karen approached.

[23] The mayor of Grand Isle, Louisiana evacuated the island on October 4, while residents were also ordered to flee the Lafourche and Plaquemines parishes.

[25] Louisiana Governor Bobby Jindal authorized the mobilization of the state's National Guard members to active duty.

[32] On October 15, the extratropical remnants of Karen was situated offshore of northeast Florida, causing coastal flooding in parts of Jacksonville.

[40] A precautionary evacuation took place at a mobile home trailer park in Hellam Township, due to river flooding associated with Kreutz Creek.

In New Castle County, the strong winds caused wave action to lap over a sea wall in Bay View Beach, south of Port Penn.

The strong winds blew sand into the left lane of northbound Delaware Route 1, near the Indian River Inlet Bridge.

[59] The runoff from the heavy rain that fell caused minor flooding along the Red Clay Creek Basin on October 11.