Preliminary Report
Hurricane Frederic
29 August - 15 September 1979

1979 PRELIMINARY REPORTS

Tropical Storm Ana (TS)
Hurricane Bob (1)
Tropical Storm Claudette (TS)
Hurricane David (5)
Tropical Storm Elena (TS)
Hurricane Frederic (3)
Hurricane Gloria (2)
Hurricane Henri (1)

a. Synoptic History

The tropical wave from which Frederic developed left the west African coast late on August 27th with little to distinguish it from most other waves. By midday on August 28, however, satellite pictures showed a rather large, circular area of convection south of the Cape Verde Islands. Peripheral ship and satellite data indicated that a tropical depression had formed by 0600 UTC on August 29. The depression gradually strengthened while moving westward at 21 mph for the next 24 hours and reached tropical storm strength near 11.5°N 36.0°W about 1200 UTC on the 30th. Frederic continued at a remarkably steady 21 mph foward movement for the next 48 hours while gradually turning to the northwest. Conditions appeared ideal for Frederic to become a very intense hurricane as David had in the same area. An eye became visible on infared satellite pictures about 0600 UTC on September 1 and Frederic was upgraded to a hurricane near 13°N 49°W.

About this time the outflow from David, which had become a very intense hurricane lashing Hispaniola, began to descend from the northwest right over Frederic, and the newborn hurricane weakened to a tropical storm again by 0000 UTC on September 2. Frederic gradually turned more to the west and decelerated with the weakening trend continued until winds finally dropped below storm strength just north of Haiti about 1800 UTC on September 6.

Frederic passed over Puerto Rico and Dominican Republic which helped disrupt the low level wind circulation in addition to the continued unfavourable impact of the outflow from David. The storm actually moved towards the southwest at less than 12 mph while southeast of the Dominican Republic, and then suddenly changed course towards the northwest during the afternoon of September 5 in a manner similar to David, passing just west of Santo Domingo about 0000 UTC on the 6th.

As David weakened over the northeastern U.S., Frederic continued slowly westward over or just south of the Cuban coast for the next four days. Excaping the unfavourable influence of David, Fredreic proceeded to strengthen beginning about 100 miles east of the Isles of Pines, Cuba about 0000 UTC on September 9. Frederic turned to the northwest during the next 48 hours, moving at an average speed of 5 mph, and regained hurricane intensity over the western end of Cuba about 1200 UTC September 10. Factors which probably contributed to the strengthening while the center was so close to land where the very warm sea surface temperatures of 29-30°C, the large cyclonic envelope of the storm, and the establishment of a large anticyclone at 200 mb over the storm.

Except for the trochoidal motion frequently observed with tropical cyclones, Frederic moved steadily northwest and turned to the north-northwest with increasing forward speed for the next 60 hours, the eye passing across Dauphin Island, Alabama about 0300 UTC on September 13 and crossing the coastline near the Mississippi-Alabama border about 1 hour later.

Frederic turned north and northeast and increased its forward speed to 23 mph during the next 24 hours, losing hurricane intensity near Meridian, Mississippi about 1200 UTC on the 13th and becoming part of a frontal low pressure area near the southwest corner of Pennsylvania about 1200 UTC on the 14th. The extratropical remnants of Frederic moved very rapidly northeastward through Pennsylvania, New York and western New England during the day and exited from northern Maine that evening.

b. Meteorological Statistics

The maximum sustianed winds in Frederic during its lifetime were estimated at 132 mph based on aircraft reconnaissance and pressure-wind relationships. The NOAA research aircraft reported a flight level wind of 159 mph a short time prior to landfall, very close to that observed at Dauphin Island. The lowest central pressure of 943 mb was reported by Air Force reconnaissance aircraft about 1200 UTC on the 12th, when the center was about 200 miles southeast of Mobile. However, the central pressure reported by reconnaissance aircraft during the last 6 hours was 946 mb. Unofficial pressure reports along the coast in the eye were Dauphin Island Sea Lab 943 mb, Grand Bay, Alabama 931 mb (appears unrealistic), Pascagoula Civil Defense 946 mb. Meridian, Mississippi had a minimum sea level pressure of 977 mb...the lowest in their records. Calm winds were observed at Pascagoula for about 1 hour, and over the western end of Dauphin Island. Calm winds were not observed in Mobile.

Frederic weakened approaching the Leeward Islands and post-analysis indicates sustained winds had dropped below hurricane force well before the center reached the Leeward Islands. Maximum sustianed winds were 29-35 mph with gusts of 52-69 mph.

Frederic continued to weaken to a tropical depression while over eastern Cuba, but regained hurricane status before leaving western Cuba. Heavy rains occurred over the Dominican Republic for several days after the center passed, augmenting the damage caused by David. Rains diminished as Frederic moved over eastern Cuba, but heavy rains and gale force winds were reported over western Cuba as the depression reagined hurricane strength.

As Frederic strengthened over the southeastern Gulf of Mexico, winds of 52-58 mph were reported from at Dry Tortugas during the evening of the 10th and morning of 11th.

The highest winds reported in squalls and gusts are as follows: Dauphin Island bridge 145 mph, Dauphin Island Sea Lab 137 mph before equipment destroyed; Pascagoula Ingalls Ship Yard 127 mph; Pascagoula Civil Defense 115 mph before equipment broke; Biloxi Civil Defense, Keesler AFB, and Gulfport Air National Guard all 98 mph; Mobile Airport and Civil Defense both 97 mph; Pensacola Naval Air Station 95 mph; Hattiesburg, Mississippi 90 mph; Meridian, Mississippi Airport 81 mph; Pensacola Municipal Airport 78 mph; Hancock County, Mississippi 74 mph.

Gale force winds in gusts occurred near the track of Frederic throughout eastern Mississippi, western Alabama and many sections of Tennessee, Kentucky, southern Ohio, western portions of Ohio, New York and through western New England. Along the coasts, gale force winds or higher occurred from the New Orleans east area southward to the Mississippi River delta and eastward to the Panama City area, as well as along portions of the New England coast.

1. Storm Surge Data

Tides of 8 to 12 feet above normal were reported in the hurricane warning area from Pascagoula, Mississippi to western Santa Rosa Island. Tides were 12 feet at Gulf Shores, Alabama...11 feet at Fort Morgan, Alabama....9.5 feet at Gulf State Park... 12 feet just south of Mobile Tunnel and 8 feet just north of Tunnel...10 feet on the east end of Dauphin Island and 7.5 feet on the west end...9 feet at Bayou La Batre...9 feet at Fairhope and 9 feet on western Santa Rosa Island, Florida.

2. Rainfall Data

Rainfall amounts in the Leeward Islands, Virgin Islands and Puerto Rico was 10 inches in 12 hours in eastern Puerto Rico, 12 inches in 24 hours in St. Thomas and 24 inches in 30 hours in St. Croix.

In the US rainfall amounts of 8 to 12 inches fell from Pascagoula to Mobile with 4 to 6 inches through other parts of eastern Mississippi and western Alabama, and northwestern Florida and northward through Tennessee. Amounts of 2 to 4 inches were reported along the track all the way to New England. No rainfall induced flooding of any consequence was associated with Frederic in the United States.

3. Tornadoes

A few tornadoes were reported in the Virgin Islands and Puerto Rico.

Over a dozen tornadoes were reported mostly along the Gulf coastal sections, but they resulted in no deaths or injuries and only minor property damage.

c. Casualty and Damage Statistics

There were 9 deaths attributed to Alicia; 7 in St. Maarten and 2 in US.

Seven deaths were reported in St. Maarten

Eleven storm related deaths have been attributed to Frederic in the U.S., but only 2 were caused directly.

Preliminary estimates of damage is estimated at $2.3 Billion make it likely that Frederic will rank as the costliest hurricane to ever hit the U.S. Insurance industry estimates of insured losses stand at $750 Million.

Preliminary estimates of persosons evacuated are between 300,000 and 400,000.