![]() ![]() At 1200 UTC on August 30, the tropical depression was upgraded to tropical storm status and thus named Frederic. Upon developing into a tropical cyclone, the depression moved at an unusually rapid pace westward, gradually curving towards the west-northwest and slowly intensifying in ideal conditions. At 0600 UTC on August 29, the National Hurricane Center (NHC) classified the system as a tropical depression based on observational data from ships nearby in conjunction with satellite images. The following day, satellite images indicated that the tropical wave had become more defined, and was beginning to show signs of cyclonic rotation. The precursor to Hurricane Frederic emerged as a loosely defined tropical wave off the west coast of Africa late on August 27. FEMA, which had been established only three months before Frederic hit, was the focal point for nearly $250 million in federal aid for recovery, $188 million of which went to Alabama (1979 USD). Over the United States, Frederic weakened for a final time before becoming extratropical in Pennsylvania on September 14 and dissipating the next day.ĭamage estimates vary from $6–9 billion (2008 USD), with variations due to inadequate reporting of private insurance claims as well as lack of hard data on uninsured damage. From then on, Frederic moved northwestward, intensifying to its peak intensity in the Gulf of Mexico with winds of 135 mph (215 km/h) on September 12, shortly before making landfall on the border between Alabama and Mississippi. The tropical cyclone nearly dissipated over Cuba before redeveloping on September 9 near the Isle of Youth. However, outflow from nearby Hurricane David began to inhibit further intensification and would continue to do so for roughly a week, weakening Frederic as it tracked across the Greater Antilles. ![]() ![]() Favorable conditions in the open Atlantic allowed for Frederic to reach hurricane intensity on September 1. Tracking at a steady clip westward, the primitive cyclone reached tropical storm intensity the next day. Analyses of time series of radar reflectivities and 5 min peak wind gusts at the surface indicate that the maximum surface winds near the glut occurred a few kilometers inside the radar eye.Frederic developed from a tropical depression south of the Cape Verde Islands on August 28, 1979. Land areas with the greatest wind damage were highly correlated with the location of radar-observed reflectivities ≥ 41 dB(Z). In this four-hour period, 3% of the land area within 100 km of the center had hourly rainfall > 50 mm h −1, and 39% of the same area had rain rates of 25–50 mm h -1. During the four hours that the most intense convection in the north eyewall was near the coast, maximum hourly rainfall rates were 50–75 min. Frederic’s maximum accumulated rainfall was slightly below average, relative to other hurricanes that have made landfall along the Gulf Coast of the United States. Maximum rainfall totals measured by gages and determined by radar were ∼250 mm. Raingage-radar comparisons indicate that the storm-total rainfall estimated by the radar is probably within a factor of 2 of the true. The storm-total rainfall maximum along the coast was explained by a rapid increase in the intensity and area coverage of deep convection in mesoscale rainbands in the north eyewall that occurred as the north eyewall interacted with the coastline. Calculations of storm-total rainfall indicate that local rainfall maxima tended to occur in two general areas: 1) parallel to the coast near the point of landfall, with a northward extension approximately along Frederic’s track, and 2) on a long band oriented from south-southeast to north-northwest ∼50 kin to the west of the storm track. Although the recorder taken to Pensacola was damaged in transit, the recording system at Slidell collected digital data for 26 h as Frederic moved ashore at 6–7 m s −1, approximately 125 km to the cast of Slidell. ![]() The researchers were in position at the National Weather Service offices at Slidell, Louisiana and Pensacola, Florida, a few hours before Frederic’s outer convective bands reached the Gulf Coast. In September 1979, two research teams traveled to the coastal area in the path of Hurricane Frederic to record observations of the storm’s rainbands with mobile radar recorders. ![]()
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