Tropical Storm Debby was a tropical cyclone that caused extensive flooding in North Florida and Central Florida during late June 2012. The fourth tropical cyclone and named storm of the 2012 Atlantic hurricane season, Debby developed from a trough of low pressure in the central Gulf of Mexico on June 23. At the time, Debby was the earliest fourth named storm to form within the Atlantic basin on record. Despite a projected track toward landfall in Louisiana or Texas, the storm headed the opposite direction, moving slowly north-northeast and northeastward. The storm slowly strengthened, and at 1800 UTC on June 25, attained its peak intensity with maximum sustained winds of 65 mph (100 km/h). Dry air, westerly wind shear, and upwelling of cold waters prevented further intensification over the next 24 hours. Instead, Debby weakened, and by late on June 26, it was a minimal tropical storm. At 2100 UTC, the storm made landfall near Steinhatchee, Florida with winds of 40 mph (65 km/h). Once inland, the system continued to weaken while crossing Florida, and dissipated shortly after emerging into the Atlantic on June 27.
The storm dropped immense amounts of precipitation near its path. Rainfall peaked at in Curtis Mill, Florida, located in southwestern Wakulla County. The Sopchoppy River, which reached its record height, flooded at least 400 structures in Wakulla County. Additionally, the Suwannee River reached its highest level since Hurricane Dora in 1964. Further south in Pasco County, the Anclote River and Pithlachascotee River overflowed, flooding communities with "head deep" water and causing damage to 106 homes. An additional 587 homes were inundated after the Black Creek overflowed in Clay County. Several roads and highways in North Florida were left impassable, including Interstate 10 and U.S. Route 90. U.S. Routes 19 and 98 were also inundated by coastal flooding. In Central and South Florida, damage was primarily caused by tornadoes, one of which caused a fatality. Overall, Debby caused at least $250 million in losses and 8 deaths, 7 in Florida and 1 in Alabama.
Meteorological history
During mid-June, the Intertropical Convergence Zone (ITCZ) made its annual migration northward into the southern Gulf of Mexico. Coinciding with a Madden–Julian oscillation, a weak surface low pressure area developed on June 19, and subsequently moved inland over the Yucatán Peninsula. While the system crossed the peninsula, a tropical wave moved through the northwestern Caribbean Sea on June 18. The wave reached the Gulf of Mexico on June 20 and merged with the low a few days later, spawning a trough of low pressure on June 22. Located in the southeastern Gulf of Mexico, moderate vertical wind shear caused the system to remain disorganized. Nonetheless, Air Force Reserve Hurricane Hunter aircraft indicated that the trough acquired a low-level circulation on June 23, while ships in the area reported tropical storm force winds. Thus, it is estimated that Tropical Storm Debby developed at 1200 UTC on June 23, centered about south of mouth of the Mississippi River.
Becoming a tropical storm on June 23, Debby became the earliest fourth named storm in the Atlantic basin, surpassing the old record set by Hurricane Dennis on July 5, 2005, however with 2016's Danielle the record was beaten by three days. Initially, Debby was predicted to curve westward and potentially threaten Texas. A deepening trough would curve the storm westward, while wind shear was predicted to decrease. Although the storm generated very cold cloud tops, much of the convection was located more than from the center and still displaced to the east. By 1200 UTC on June 24, the forecast path was shifted from east-central Texas to southeastern Louisiana. Despite persistent wind shear, Debby was strengthening and around that time, the storm attained its maximum sustained wind speed of 65 mph (100 km/h). Later on June 24, the National Hurricane Center noted in its next advisory that this "is a very difficult and highly uncertain forecast", citing Debby's slow movement and widespread computer forecast models.
The forecast track for Debby was shifted significantly to the east late on June 24, and it was predicted that the storm would move northward and make landfall near Panama City, Florida. Based on a dropsonde estimate, Debby attained its minimum barometric pressure of at 0000 UTC on June 25. However, the storm began to weaken due to increasing wind shear, drier air, and upwelling of cold water, caused by Debby's slow movement. It was initially composed of multiple small swirls, but consolidated into one well-defined low-level circulation by early on June 25. Due to its excessively slow movement and no prediction for acceleration, the National Hurricane Center remarked that, "the cyclone does not seem to be going anywhere anytime soon." A burst in deep convection occurred later on June 25, though adverse environmental conditions prevented re-intensification. Debby began curving east-northeastward and began to speed up on June 26, in response to a mid-latitude trough digging into the western Atlantic Ocean. While approaching the Florida Big Bend, Debby produced only a small area of deep convection on satellite imagery.
At 2100 UTC June 26, Debby made landfall near Steinhatchee, Florida with winds of 40 mph (65 km/h). The storm weakened quickly after moving inland, and by early on June 27, it was downgraded to a tropical depression, while located about north of Gainesville, Florida. Debby maintained tropical cyclone status while crossing Florida, but degenerated into a trough of low pressure by 1800 UTC on June 27. In the final advisory issued by the National Hurricane Center three hours later, the agency noted that Debby could eventually reacquire tropical characteristics. After its dissipation, however, the remnants did not regenerate into a tropical cyclone, but re-developed a new center of circulation and strengthened slightly due to baroclinic conditions. As it accelerated northward, Debby's remnants became increasingly frontal in nature, and once again degenerated into an open trough at 1800 UTC on June 30; at this time, the disturbance was located south of Newfoundland.
Preparations
Upon development of Debby on June 23, a tropical storm warning was issued from the mouth of the Pearl River to Morgan City, Louisiana, excluding New Orleans or Lake Pontchartrain. On the following day, a separate tropical storm warning was put into effect from the Mississippi and Alabama border to the mouth of the Ochlockonee River in Florida. At 1500 UTC on June 24, the tropical storm warning was extended to the mouth of the Suwannee River. Simultaneously, a tropical storm watch was issued from the Suwannee River to Anclote Key. These were all canceled at 1500 UTC on June 25, though a tropical storm warning was then implemented from Destin to Englewood, Florida. Early on June 26, a tropical storm warning was issued from Mexico Beach to Englewood, Florida. By 2100 UTC that day, the tropical storm warning was extended to the mouth of Steinhatchee River in Florida. This was discontinued after Debby became a tropical depression.
Several additional preparations took place in addition to tropical cyclone warnings and watches. According to the Federal government of the United States, nearly 25% of crude oil and natural gas production in the Gulf of Mexico was shut down. In Louisiana, Governor Bobby Jindal declared a state of emergency. On June 24, voluntary evacuations were issued for several areas in northwest Florida during the approach of the storm, especially Taylor and Wakulla Counties. Governor of Florida Rick Scott also declared a state of emergency on June 25. Additionally, mandatory evacuations were issued for St. George Island, Alligator Point, and other low-lying areas of Franklin County.
Impact Throughout the Southeastern United States, eight people were killed in relation to Tropical Storm Debby. Of these, seven took place in Florida and one in Alabama. Throughout Central and South Florida, the outer bands of the storm spawned 13 tornadoes: five in Collier County, two in Glades County, one in Hardee County, two in Highlands County, one in Miami-Dade County, and two in Palm Beach County. Overall, losses from the storm were estimated to have reached at least $250 million.
Florida
North Florida and Panhandle
Throughout June 25, an intense complex of thunderstorms developed to the north of Debby's center and produced torrential rains over the Florida Panhandle for much of the day. Many areas received rainfall in excess of . Precipitation peaked at in Curtis Mill, which is located in Wakulla County. In Panacea, a Mesonet station recorded a 24‑hour rainfall of . Rainfall caused numerous small creeks, streams, and rivers to rapidly exceed their banks and flood adjacent communities. The Sopchoppy River crested at , which was a record height. Numerous homes were flooded, some up to the second story. Two bridges were damaged, and numerous roads around the county were washed out or closed. Over 400 structures were affected by flooding, including more than 170 mobile homes and nearly 200 single-family residences. Of these structures, 40 were destroyed, 61 had major flood damage, 41 suffered minor flood damage, and 271 were affected by flooding. Additionally, coastal flooding impacted the county, with a storm surge of and tides up in St. Marks. Numerous roads were underwater and several area businesses received water intrusion in that city. U.S. Route 98 was over-washed just north of St. Marks. As a result, mandatory evacuations were ordered south of U.S. Route 98 and around the Sopchoppy River. In total, 67 people required rescuing. Losses throughout the county were assessed at $9.09 million.
The storm also produced adverse effects in Franklin County. In Apalachicola, a gust of was observed as well as of rainfall on June 24, resulting in widespread flash flooding. The John Gorrie Memorial Bridge connecting Apalachicola to Eastpoint was closed on June 24 due to high winds. A wind gust of was reported at the Apalachicola Regional Airport. The St. George Island Bridge, a bridge connecting Eastpoint to St. George Island over the Apalachicola Bay, was also closed on June 24 due to high winds. The bridge was opened later that day as both St. George Island and Alligator Point were put under a mandatory evacuation, requiring all people to leave immediately, and those remaining on the islands subject to arrest. St. George Island, a popular resort community and tourist destination, lost all power on June 24 due to high winds destroying three power poles in the Apalachicola Bay; a Progress Energy spokesperson stated that it could be days before power was restored because the conditions are too unsafe for workers. In Bay County, moderate beach erosion occurred, with a storm surge reaching and storm tide of in Panama City. Flooding forced the closure of a few roads in Jefferson County, including U.S. Route 27 west of U.S. Route 19.