Early on the morning of August 10, 1980, major Hurricane Allen roared ashore over Brownsville, Texas. A classic Cape Verde hurricane, Allen had cut a path across the Caribbean Sea and Gulf of Mexico over the previous six days, to become one of the landmark storms of the era. It was also provided a cornucopia of scientific information which led to insights about storm dynamics, precipitation structure, and eyewall replacement cycles.
On August 1st, Allen formed from an easterly wave which had moved off of Africa two days before. For the next two days, the storm steadily organized and strengthened, becoming a hurricane on August 3rd. It then began to rapidly intensify as it approached the Windward Islands and passed north of Barbados and very near to St. Lucia as a Category-3 hurricane. The destruction on St. Lucia was particularly catastrophic with 6 people killed and US$235 million in damage. And Allen continued to rapidly intensify, becoming a Category-5 storm as it passed south of Puerto Rico.
Although the hurricane’s eye wove between Hispañola, Jamaica, and Cuba, the large storm managed to inflict death and destruction on those islands. The rampage through the Greater Antilles cost 238 lives and over half a billion US dollars in destruction, the majority in Haiti. During this passage, Allen diminished to a Category-4 hurricane, but as it neared the Yucatan Channel west of Cuba on August 7th, it again regained Category-5 status. The eye passed north of the Yucatan, but Allen dumped heavy rain on the peninsula.
Allen was constantly monitored by satellite, Air Force and NOAA aircraft, and land-based radar during its passage across the Gulf of Mexico. Another cycle of slight weakening and restrengthening was noted during this portion of Allen’s track. But as it approached the U.S./Mexico border, it once again diminished to Category-4 status. The hurricane brought a 12-foot storm surge to coastal Texas, with sustained winds estimated at 125 mph (205 km/hr), and over 20 inches of rain to the area. Since this portion of Texas and Mexico were sparsely occupied, casualties were low, with only six deaths reported in Texas. However, Allen caused nearly US$300 million in damage at landfall, nearly a third of that as a result of a hurricane-spawned tornado in Austin.
Allen provided a trove of scientific information. The recently-acquired NOAA P-3 aircraft flew nine missions into the hurricane in addition to four flights carried out by the NOAA C-130. A number of these were simultaneous multi-aircraft missions while Allen was at Category-5 status. The P-3’s lower fuselage and tail radars provided unprecedented detailed views of the eyewall and rainbands of a major hurricane. Careful study of the radar and flight-level data collected led to the formulation of the Eyewall Replacement Cycle paradigm, provided statistics on tropical cyclone vertical wind motions, and better understanding of the primary and secondary circulation structure. Attempts were made by National Hurricane Research Laboratory and National Weather Service scientists to record the land-based radars at Victoria and Brownsville, Texas, but technical difficulties prevented any useful data being collected.
On a more personal note, Allen provided many research scientists with their first (and for some only) encounter with a hurricane of this magnitude. A NOAA reconnaissance flight on August 6th proved particularly turbulent. The shaking from updraft/downdraft couplets knocked the coffee pot in the galley loose as well as a cabinet-full of data tapes and a 20-man life raft. After this memorable flight, one scientist kissed the ground upon landing at Miami International Airport and resigned from the National Hurricane Research Laboratory days later, never to fly hurricanes again.
NHRL/HRD papers as the result of Hurricane Allen data:
- Jones, W. L., P. G. Black, V. E. Delnore, and C. T. Swift, 1981: Airborne microwave remote-sensing measurements of Hurricane Allen. Science, 214, 274–280.
- Willoughby, H. E., J. A. Clos, and M. B. Shoreibah, 1982: Concentric eyewalls, secondary wind maxima, and the development of the hurricane vortex. J. Atmos. Sci., 39, 395–411.
- Willoughby, H. E. and M. B. Chelmow, 1982: Objective Determination of Hurricane Tracks from Aircraft Observations. Mon. Wea. Rev., 110, 1298–1305.
- Shapiro, L. J. and H. E. Willoughby, 1982: The Response of Balanced Hurricanes to Local Sources of Heat and Momentum. J. Atmos. Sci., 39, 378–394.
- Hawkins, H. F., 1983: Hurricane Allen and Island Obstacles. J. Atmos. Sci., 40, 1360–1361.
Shapiro, L. J., 1983: The Asymmetric Boundary layer Flow Under a Translating Hurricane. J. Atmos. Sci., 40, 1984–1998.
Jorgensen, D. P., 1984: Mesoscale and convective-scale characteristics of mature hurricanes. Part I: General observations by research aircraft. J. Atmos. Sci., 41, 1268–1285.
- Jorgensen, D. P., 1984: Mesoscale and Convective-Scale Characteristics of Mature Hurricanes. Part II. Inner Core Structure of Hurricane Allen (1980). J. Atmos. Sci., 41, 1287–1311.
Jorgensen, D. P., E. J. Zipser, and M. A. LeMone, 1985: Vertical motions in intense hurricanes. J. Atmos. Sci., 42, 839–85
Willoughby, H. E., D. P Jorgensen, R. A. Black, and S. L. Rosenthal, 1985: Project Stormfury: A scientific chronicle. Bull. Amer. Meteor. Soc., 66, 505–5
Marks Jr.,F. D., 1985: Evolution of the Structure of Precipitation in Hurricane Allen (1980). Mon. Wea. Rev., 113, 909–930.
- Black, R. A. and J. Hallett, 1986: Observations of the distribution of ice in Hurricanes. J. Atmos. Sci., 43, 802 – 822.
- Jones, R. W., 1986: Mature Structure and Motion of a Model Tropical Cyclone with Latent Heating by the Resolvable Scales. Mon. Wea. Rev., 114, 973–990.
- Samsury, C. E., and E. J. Zipser, 1995: Secondary Wind Maxima in Hurricanes: Airflow and Relationship to Rainbands. Mon. Wea. Rev., 123, 3502–3517.
- Willoughby, H. E., and M. E. Rahn, 2004: Parametric Representation of the Primary Hurricane Vortex. Part I: Observations and Evaluation of the Holland (1980) Model. Mon. Wea. Rev., 132, 3033–3048.
- Zhang, J. A., F. D. Marks, M. T. Montgomery, and S. Lorsolo, 2011: An Estimation of Turbulent Characteristics in the Low-Level Region of Intense Hurricanes Allen (1980) and Hugo (1989). Mon. Wea. Rev., 139, 1447–1462.
Gopalakrishnan, S. G., F. Marks Jr., J. A. Zhang, X. Zhang, J.-W. Bao, and V. Tallapragada, 2013: A Study of the Impacts of Vertical Diffusion on the Structure and Intensity of the Tropical Cyclones Using the High-Resolution HWRF System. J. Atmos. Sci., 70, 524–541.
Zhang, J. A., and M. T. Montgomery, 2012: Observational Estimates of the Horizontal Eddy Diffusivity and Mixing Length in the Low-Level Region of Intense Hurricanes. J. Atmos. Sci., 69, 1306–1316.