Early August Updated Forecast of Atlantic Seasonal Hurricane Activity for 1994

摘要

This paper presents details of the author's forecast for the amount of tropicalcyclone activity expected to occur in the Atlantic Ocean region including the Caribbean Sea and the Gulf of Mexico during 1994. This forecast is based on the author and colleague's ongoing research relating the amount of seasonal Atlantic tropical cyclone activity to five basic physical parameters. These are: (1) the quasi-Biennial Oscillation (QBO) of equatorial stratospheric wind; (2) the El Nino Southern Oscillation (ENSO); (3) West African Rainfall (AR) anomalies; (4) anomalous west to east gradients of surface pressure and surface temperature (delta PT) in West Africa during February through May; and (5) Caribbean Basin Sea Level Pressure and Upper Level Zonal Wind Anomalies (SLPA and ZWA respectively). Information received by the author through 4 August 1994 indicates that the overall 1994 hurricane season should be below average with about 4 hurricanes (average is 5.7), 7 named storms (average is 9.2) of at least tropical storm intensity, a total of about 12 hurricane days (average is 23), 30 named storm days (average is 46) and total Hurricane Destruction Potential (HDP) of 35 (average is 69). It is also expected that there should be only one intense or major hurricane of Saffir/Simpson intensity category 3, 4 or 5 this season (average is 2.1) and only about 1 major hurricane day (average is 4.5). These parameters represent an overall measure of total hurricane and tropical cyclone activity which is only about 55% of the last 44-year average. The amount of hurricane activity in this forecast has been reduced from that in the author's 19 November 1993 forecast and update 7 June 1994 forecast. This forecast reduction is due to the slower than anticipated dissipation of the current El Nino, new estimates of below average West African rainfall, and much above average values of June-July Caribbean basin sea level pressure.