Regional And Mesoscale Meteorology Team
Daily Satellite Discussion
Monday October 13,1997
On September 6, 1995 at 15Z hurricane Luis was located just northeast of Puerto Rico and was moving to the west-northwest. This hurricane had maximum sustained winds of 115 knots and a surface pressure of 943mb. A one hour (15Z to 16Z) average image of Luis is shown in Fig. 1, with the manually-tracked upper level (~200 mb) winds for that same period. Note the asymmetries both in direction and strength of the wind field. A closer view of the center of the storm is shown in Fig. 2, overlaid with divergence as calculated from the satellite derived wind field. The winds result in a strong wave number one asymmetry in the divergence field with convergence(divergence) to the right and front (left and rear) of the hurricane's motion. In a similar fashion vorticity is calculated and displayed over the same one hour average image in Fig. 3. In the inner radii of this very intense hurricane the upper level outflow is strongly cyclonic.
In the future, satellite derived wind sets, along with winds from aircraft reconnaissance flights, will produce a detailed three-dimensional view of the wind field of tropical cyclones. The use of such wind fields should result in better forecasts of tropical cyclone intensity.
