Occurrence of tropical depressions and cyclones in the north eastern Australian region during the season 1958-1959

During the year ended 30th June 1959 there were only six tropical disturbances which were associated with gale force winds. Of these the February 1959 cyclone was the third most intense on record. This storm was associated with a central pressure of 948 mb (28.00 ins) and 116 mph winds lasting for about two hours at Bowen. This cyclone could almost be described as "classical" in regard to its behaviour in relation to the various forecasting aids. Concerning these, the cyclone season confirmed previous experience in regard to the value of certain aids. Those found to be of particular value were sferics for detection, radar for tracking, divergence on the warm side of the 200 millibar jet and the “Durst Sutcliffe” effect for development, Mintz’s rule for steering when a horizontal temperature gradient was clearly established, and the 200 millibar zonal discontinuity whenever the disturbance was clearly to one side or the other of the discontinuity. The season gave increasing evidence of the fact that there appears to be a direct relationship between the strength of the 200 millibar jet and the intensity and speed of deepening of the surface disturbance. When cyclones were well developed it was possible to forecast direction of movement with a fairly high degree of accuracy but some difficulties were evident in this respect in the case of the smaller and weaker disturbances.