140 North Atlantic Hurricanes Contributed by African Easterly Waves North and South of the African Easterly Jet

Thursday, 3 April 2014
Golden Ballroom (Town and Country Resort )
Joshua J. Alland, University at Albany, SUNY, Albany, NY; and T. C. Chen

Handout (7.2 MB)

Although tropical cyclone (TC) track forecasting has improved within the last 10 years, intensification forecasting remains difficult. Understanding TC intensification is of utmost importance, as intensification is not well predicted by operational meteorological forecasts. This study aims to examine African Easterly Waves (AEWs), which are weather disturbances that travel westward from the western coast of Africa. Some of these waves dissipate quickly, but others develop into TCs and in some cases, powerful hurricanes. It is hypothesized that waves developing north of the African Easterly Jet (AEJ), or northern waves, do not strengthen, as moisture is restricted in this region due to the Saharan Air Layer. On the contrary, it is hypothesized that waves developing south of the AEJ, or southern waves, have a greater likelihood of eventual intensification due to ample moisture in this region. Results suggest that this is true. In addition, northern waves are examined from 1990-2010 to determine the physical mechanism that causes these waves to penetrate and cross the AEJ. Preliminary results suggest that a combination of strong northerly flow and an AEJ positioned sufficiently high in the atmosphere enhance the likelihood of penetration and crossing.
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