Preliminary Report
Tropical Storm Alberto
30 June - 07 July 1994

1994 PRELIMINARY REPORTS

Tropical Storm Alberto (TS)
Tropical Storm Beryl (TS)
Hurricane Chris (1)
Tropical Storm Debby (TS)
Tropical Storm Ernesto (TS)
Hurricane Florence (2)
Hurricane Gordon (1)

Tropical Storm Alberto caused minor damage and no casualties when it came ashore in the Florida panhandle. Although the winds then quickly diminished, the remnants meandered for four days through eastern Alabama and western Georgia, producing record-breaking rainfall, and floods that over the course of a week took 28 lives in Georgia and 2 lives in Alabama. Alberto caused damage estimated at $500 Million.

a. Synoptic History

Alberto's origin is traced to a tropical wave detected in Dakar, Senegal rawindsonde data on 18 June. Satellite pictures indicate that the wave then progressed steadily westward for several days accompanied by a broad area of low clouds and a hint of dust. The wave produced showers over the Lesser Antilles, but little deep convection occurred until a cluster of thunderstorms developed over the waters just north of the Virgin Islands and Puerto Rico early on the 26th. When the cluster neared the central Bahamas two days later, however, it was sheared apart by westerly winds aloft associated with a short-wave trough progressing eastward into the Atlantic.

Beginning on the 28th, water vapor imagery and sounding data showed the axis of a narrow mid- to upper-level trough or cyclonic shear zone becoming nearly stationary from south Florida to the nortern Yucutan peninsula. (This feature developed between the short-wave trough noted above and a slow-moving east-west oriented trough over the southern Gulf of Mexico.) Southwesterly winds ahead of the axis were rather light. Hence, when the tropical wave moved across Cuba and the adjacent waters of Caribbean Sea on the 29th, it encountered a light vertical wind shear. Deep convection quickly increased and became concentrated over central Cuba. Rawindsonde data from Camaguey, Cuba indicated the pressure of a closed low at 850 and 700 mb. A little later, surface data showed the first signs of an associated surface low in that area.

By midday on the 30th, the disturbed weather crossed the Isle of Youth and was centered near the Western tip of Cuba. The first reconnaissance flight into the area, by a NOAA aircraft, indicated a well-defined circulation at 1000 feet altitude and a central pressure of 1008 mb at 1902 UTC. Based on those observations, and earlier ship and land reports, it is estimated that the system became Tropical Depression One with 30 mph surface winds near 0600 UTC on the 30th. The depression initially moved westward at about 8 mph.

A low aloft was then forming within the trough just to the west of the depression. That low moved quickly westward and was located over the south-central Gulf of Mexico by the 1st of July. In addition, the next mid-latitude short-wave trough swept eastward across the northern Gulf. This combination put the depression in a modest, mainly southerly steering flow and shear. The depression gradually turned more to the north, but remained rather poorly-organized with a partially exposed low-level center seen on satellite pictures.

The low aloft shifted farther away from the depression, into the southwestern Gulf. Reconnaissance aircraft data from the U.S. Air Force Reserves indicates that the depression strengthened to become Tropical Storm Alberto near 0000 UTC on the 2nd. Later that day, the ship Robert E. Lee reported 51 mph winds about 40 nautical miles to the north of Alberto's center.

A third short-wave trough approached the central Guf states late on the 2nd. The steering flow ahead of the trough axis accelerated Alberto northward, from 8 to 14 mph, toward the Florida panhandle. Alberto continued to strengthen with its circulation center becoming more embedded within deep convection. Alberto was at its peak intensity, 993 mb and 63 mph winds, when the center made landfall near Dustin, Florida at 1500 UTC on the 3rd. At that time, visible satellite pictures showed a recessed spot near the middle of the central cloud feature that may have indicated the first stages in the development of an eye.

Winds then quickly subsided and Alberto's central pressure rose rapidly. Alberto weakened back to a tropical depression near 0000 UTC on the 4th. Alberto's northward progress was then retarded and eventually halted when it was bypassed by the third short-wave trough and blocked by an area of high pressure that built that trough, to the north of Alberto.

By 1800 UTC on the 4th, the central pressure increased to 1014 mb and surface winds speeds decreased to around 23 mph. Surface data indicate that the cyclonic circulation spun down very slowly after that time. In addition, satellite pictures and WSR-88D radar data continued to show a well-defined, cyclonically turning cloud and reflectivity pattern moving slowly through eastern Alabama and western Georgia until late on 7 July. The system produced locally torrential rain during that period, inducing numerous floods that continued many days after the tropical cyclone dissipated.

b. Meteorological Statistics

The highest officially recorded 1-min wind speed at the surface was 40 mph, observed at Eglin AFB/Valparaiso (VPS) and Hurlburt Field (HRT). The Coast Guard Station at Destin recorded a gust to 75 mph. VPS had a peak gust of 68 mph. An unofficial gust to 86 mph at 1405 UTC was reported from a portable anemometer in an open exposure in Destin. This comparable to the highest wind speed just above the shoreline shown by Eglin AFB/Valparaiso (KEVX) WSR-88D radar about 50 minutes later. The reconnaissance flight at about that time had peak 1500 feett flight-level winds of about 77 mph.

Alberto's estimated minimum pressure of 993 mb is based on reconnaissance measurements of that value and an unofficial observation of 994 mb at Destin.

1. Storm Surge Data

A storm tide of 5 feet was estimated near Destin. A 3 foot storm surge (NGVD) occurred at Panama City, Panama City Beach, Turkey Point and Apalachicola.

2. Rainfall Data

The Isle of Youth, Cuba had about 10 inches of rain while Alberto became organized into a depression. Rainfall totals for the landfall area in northwest Florida were about 5 inches. Record rains occurred farther to the north in association with the slowly-weakening depression over the following several days. The KEVX WSR-88D radar indicated a roughly 50 nautical miles wide swath of greater than 5 inches of rainfall extending from near Crestview, Florida to west-central Georgia during the 35-hour period ending near 2000 UTC on the 6th. It also showed a maximum of 14.6 inches for that period.

Americus, Georgia received more than 21 inches of rain in a 24-hour period ending on the morning of 6 July and 27.61 inches fell there from 4-7 July. Macon, Georgia established their one-day rainfall record with 10.25 inches. When the depression headed westward on the 6th, heavy rains returned to the Florida panhandle and rainfall up to 8 inches was estimated to have fallen on the night of the 6th-7th near D'Iberville, Mississippi.

Many rivers and creeks in Georgia and in the Florida panhandle flooded. The Flint River crested above flood stage by about 24 feet in Albany, Georgia. Some dams were overtopped and broken by the river torrents in Georgia.

c. Casualty and Damage Statistics

Although 13 people were rescued offshore, no casualties and mostly minor damage (e.g., limited beach erosion, downed trees and power lines) are attributed to Alberto through about the first day following landfall. The most extensive beach erosion (up to 14 feet) was reported on Cape San Blas.

Subsequent rains resulted in the failure of two hydroelectric dams and 82 small dams. The associated floods, in some instances exceeded 100-year event thresholds. The floods were directly responsible for the loss of 28 lives in Georgia and 2 in Alabama. Some of the fatalities were reported as much as a week after Alberto's landfall and days after the last vestiges of Alberto's circulation and rain disappeared.

The American Insurance Services Group preliminary estimated Alberto's damage at $500 Million, of which $250-300 Million was insured. A component of the insured loss, damage to buildings and vehicles, was estimated at $70 Million in Georgia, $15 Million in Florida and $10 Million in Alabama, and likely to rise further. Crop losses alone accounted for a $100 Million loss in Georgia. The total loss in Florida has been estimated at about $80 Million.

About 20,000 people evacuated from Albany, Georgia, 2,000 people left Bainbridge, Georgia, and about 4,000 people were evacuated from the Florida panhandle because of the threat of fresh-water flooding. Evacuations also occurred in parts of Alabama.

A total of 55 counties in Georgia, 13 in Florida, and 10 in Alabama were declared disaster areas.