Hurricanes are one of nature’s most powerful storms. They produce strong winds, storm surge flooding, and heavy rainfall that can lead to inland flooding, tornadoes, and rip currents.
What is a hurricane?
Hurricanes, known generically as tropical cyclones are low-pressure systems with organized thunderstorm activity that form over tropical or subtropical waters. They gain their energy from warm ocean waters.As storm systems strengthen into hurricanes, the surface winds move continuously in a circular motion. Meteorologists refer to this pattern as “closed circulation." The direction of circulation is different depending on where the storm is located: it is counter-clockwise in the Northern hemisphere and clockwise in the Southern hemisphere.
These rotating winds lead to the development of the characteristic “eye” of the hurricane, the calm, clear center of the storm. The eye is surrounded by the eye wall , where winds are strongest.
Tropical cyclones are classified by their maximum wind speed.
Winds less than 39 mph: Tropical depressions
Winds 39-73 mph: Tropical storms
Winds 74 mph or greater: Hurricanes
Major hurricanes have winds of at least 111 mph and can reach speeds of over 180 mph, with gusts of 200 mph.
How do Hurricanes Form?
On the west coast of Africa to the north of the equator, a typical towering thunderstorm cloud is present but it could soon change into a hurricane, there are many other thunderstorms that form in that particular area. And all those dark clouds start rotating around this creates an area of low atmospheric pressure which is known as the low depression area. It draws enough energy from the warmth of ocean water. The cycling stromes might grow as strong thunderstorms. In many other warm tropical areas it occurs in the world. In the Atlantic, these storms are called hurricanes and in different parts of the world, these are called typhoons or tropical storms. For the formation of hurricanes, warm water must be humid, moist air is needed in that region. Now, when the humid air is rising above at a low-pressure zone or area the water then is released from the air creating storm clouds. As it rises hurricanes air also starts rotating. Towards the northern hemisphere, the air gets curved which is present in the middle of the hurricanes and then the same air rotates towards the southern hemisphere forming clockwise and anticlockwise rotation.
To conclude , Forecasts during Hurricane Elena derived from the three different NWS numerical forecast models showed considerable differences, especially at the time three critical changes in direction of movement of the hurricane occurred. The consequence of the different forecasts from the three numerical models was a loss of confidence by NHC forecasters.
The National Meteorological Center should continue to make increased efforts to improve its ability to analyze and forecast tropical cyclones. This should include improvement in accuracy as well as a single unified forecast presentation for use by NHC.
Comments
Post a Comment