Upper Tropospheric Cyclonic Vortex - Interaction With Tropical Cyclones

Interaction With Tropical Cyclones

The summer TUTT in the Southern Hemisphere lies over the trade wind region of the east central Pacific and can cause tropical cyclogenesis offshore Central America. University of Hawaii Professor James C. Sadler has documented tropical cyclones over the eastern North Pacific that were revealed by weather satellite observations, and suggested that the upper-tropospheric circulation is a factor in the development, as well as the life history, of the tropical cyclones. Ralph Huschke and Gary Atkinson proposed that a moist southwest wind that results from southeast trades of the eastern South Pacific deflecting towards the Pacific coasts of Central America between June and November, is known as the "temporale". Temporales are most frequent in July and August, when they can reach gale force and cause rough seas/swell. The area of heavy rain is generally located in the northeast quadrant approximately 5° of latitude (or 555 kilometres (300 nmi)) from the eye. In the western Pacific, tropical upper tropospheric lows are the main cause for the few tropical cyclones which develop north of the 20th parallel north and east of the 160th meridian east during La Nina events.

Trailing upper cyclones and upper troughs can cause additional outflow channels and aid in the intensification process of tropical cyclones. Developing tropical disturbances can help create or deepen upper troughs or upper lows in their wake due to the outflow jet stream emanating from the developing tropical disturbance/cyclone. In the western North Pacific, there are strong reciprocal relationships between the areas of formative tropical cyclones and that of the lower tropospheric monsoon troughs and the tropical upper tropospheric trough. Tropical cyclone movement can also be influenced by TUTT cells within 1,700 kilometres (920 nmi) of their position, which can lead to non-climatological tropical cyclone tracks.