Tropical Storm Debby has been moving over land after making landfall in the Big Bend, Florida, area on Monday morning with winds of 80 mph, gradually losing strength but still producing large amounts of rain and potentially catastrophic impacts. threaten.
At 11 a.m. ET Tuesday, Debbie was a low-level tropical storm with winds of 40 mph located off the Georgia coast about 15 miles south of Savannah, slowly heading northeast at 6 mph move.
Debbie Weather Forecast
The center of Debbie is moving over the water and is expected to remain off the South Carolina coast through Thursday morning. Debbie's water temperatures will reach 28-29 degrees Celsius (82-84°F), and there will be plenty of thermal energy to steadily re-intensify. The NHC predicts winds will increase to 60 mph by Thursday when Debbie makes its second landfall. During this time, Debbie will be crawling at a forward speed of nearly 5 mph, performing sea loops. This will allow this rejuvenated storm to bring catastrophic heavy rains to much of coastal South Carolina and southern North Carolina.
This historic flooding event will finally begin to weaken on Friday and Saturday, when a trough of low pressure will pull Debbie northeastward. However, Debbie's flooding threat will then spread to the mid-Atlantic and northeastern United States: widespread rainfall of 6-8 inches is expected over the next five days (Figure 1), causing severe flooding. A large portion of Tuesday's rainfall totals are not expected to be directly related to Debbie: Moisture pushing north of Debbie will collide with an east-west frontal system that could bring 3-6 inches of rain in many locations. A moderate risk warning for excess rainfall and flash flooding was issued Tuesday for eastern Pennsylvania, much of New Jersey, and southeastern New York, including New York City and Philadelphia. Tuesday's rain will only heighten the risk of additional flooding later this week when Debbie eventually moves northeast.
NOAA's excess rainfall discussion, held at 4:27 a.m. ET on Tuesday, puts parts of coastal Georgia, South Carolina and North Carolina at “high risk” for heavy rainfall on Tuesday , and warned of “multiple severe to catastrophic flooding in rural and urban areas” in areas with rising rivers, particularly in eastern South Carolina. They expect high-risk areas to cover much of coastal South Carolina and parts of southeastern North Carolina on Wednesday and Thursday. In the United States, only about 4% of days are classified as high-risk areas, but these areas account for about one-third of all flood deaths and about 80% of flood-related losses. The three-day outlook warns that “widespread, multiple flash flooding is possible, with the potential for severe and potentially catastrophic flooding.”
Florida's major rivers flood
South of Tampa Bay, which received up to 21 inches of rain on Sunday and Monday (see tweet above), the Manatee River peaked at 20.12 feet Tuesday morning, breaking the previous record of 20.0 feet set on July 21, 1962. The Little Manatee River also saw record flooding. The National Oceanic and Atmospheric Administration (NOAA) is forecasting significant river flooding on three northern Florida rivers on Wednesday: the Suwannee, St. Mary's and Santa Fe rivers.
Up to a foot of rain has fallen in South Carolina
Measurements by the South Carolina CoCoRaHS rain gauge network during the 24 hours between 7 a.m. and 9 a.m. EDT Tuesday showed heavy reports of more than 10 inches of rain, with two rain stations near the southeast coast of Charleston reporting amounts of rain. is 12 to 13 inches (see tweet below). Additional rainfall amounts of 8-20 inches are expected across much of coastal South Carolina, jeopardizing the state's all-time rainfall record for tropical cyclones (23.63 inches from Hurricane Florence in 2018).
NOAA is currently forecasting major river flooding later this week on three rivers in Georgia, one river in South Carolina and two rivers in North Carolina.
Tornadoes rip through South Carolina coast
The National Oceanic and Atmospheric Administration (NOAA) Storm Prediction Center issued a “slight risk” (Level 2 of 5) risk level for coastal areas of South Carolina and southernmost North Carolina on Tuesday, mainly due to the supercell There is a brief risk of tornadoes from the storm, which may develop in areas of favorable wind shear to the north. Several tornadoes (and/or waterspouts moving ashore) were reported in South Carolina overnight, including one that destroyed numerous trees on Edisto Island and another that destroyed near Moncks Point trees.
The next tropical wave to watch will be in the Caribbean
Tropical waves that swept across the southern Caribbean Sea on Tuesday will be monitored over the next few days. The disturbance is centered off the northern coast of Venezuela and is moving westward at about 10 mph with unorganized showers and thunderstorms (convection) ahead. As the wave embedded in the moist atmosphere and moved across the southern Caribbean Sea, sea surface temperatures were unusually warm at 29 degrees Celsius (84 degrees Fahrenheit), about 1°C (2°F) above average, but wind shear was strong Any progress should be suppressed for the next few days.
As suggested by some members of the GFS and European Group members, this wave may turn toward the northwest Caribbean and into the southern Gulf of Mexico early next week (see Figure 3). However, it seems more likely that this wave will continue westward into Central America or southern Mexico before it has a chance to become a powerful tropical cyclone.
In a Tropical Weather Discussion posted at 8 a.m. ET Tuesday, the National Hurricane Center gave the probability of the disturbance becoming at least a tropical depression within 2 days and 30 percent within 7 days. The next name on Atlantic's list is Ernesto.
