Monday, 21 January 2013

Can the current Tropical Low Pressure turn into a cyclone?

A nice question were asked, what's going to happen to the tropical low when it moves over the ocean, will it disappear or could it turn into a cyclone ?

The formation of tropical cyclones is the topic of extensive ongoing research and is still not fully understood. While six factors appear to be generally necessary, tropical cyclones may occasionally form without meeting all of the following conditions. In most situations, water temperatures of at least 26.5 °C (79.7 °F) are needed down to a depth of at least 50 m (160 ft); waters of this temperature cause the overlying atmosphere to be unstable enough to sustain convection and thunderstorms. Another factor is rapid cooling with height, which allows the release of the heat of condensation that powers a tropical cyclone. High humidity is needed, especially in the lower-to-mid troposphere; when there is a great deal of moisture in the atmosphere, conditions are more favorable for disturbances to develop. Low amounts of wind shear are needed, as high shear is disruptive to the storm's circulation. Tropical cyclones generally need to form more than 555 km (345 mi) or five degrees of latitude away from the equator, allowing the Coriolis effect to deflect winds blowing towards the low pressure center and creating a circulation. Lastly, a formative tropical cyclone needs a pre-existing system of disturbed weather, although without a circulation no cyclonic development will take place. Low-latitude and low-level westerly wind bursts associated with the Madden-Julian oscillation can create favorable conditions for tropical cyclogenesis by initiating tropical disturbances.A tropical cyclone can dissipate when it moves over waters significantly below 26.5 °C (79.7 °F). This will cause the storm to lose its tropical characteristics (i.e. thunderstorms near the center and warm core) and become a remnant low pressure area, which can persist for several days.

Great interest is expressed by many about this past weekend's heavy rain, the causes and the probability of the TLP system possibly developing into a cyclone. Are these system rare and uncommon? In my opinion not. We have experienced similar TLP systems in the past (2011 + 2010) which also caused damage, deaths and flooding. Definitely in my opinion not uncommon or rare. The following satellite images downloaded by me in January 2010 reflect such a system which caused severe flooding in parts of South Africa.

If this tropical low develops further it will be a first that I know of. We should however still keep an eye on this Tropical Low Pressure system and it's movements.

- SAWDOS + Wikipedia + SAT24

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