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Tropical Cyclones end their lives in a variety of ways. We will concentrate on the major ones here.
One way a storm can end is simply to move into a high shear environment. Here the low level circulation is stripped of its thunderstorms and heat and it slowly fills and cools. Other hurricanes move into areas of convergent upper level winds and the center slowly fills. Sometimes weak hurricanes move close to nearby stronger hurricanes and again are sheared apart or subsidence from the larger storm over the small storm inhibits convection. Other hurricanes merge with mid-latitude systems and lose their tropical features. By far and away most cyclones end for one of two reasons: recurving into mid-latitudes and then moving over cold water or by making landfall.
First, at least in the Atlantic, is death by recurvature. Here storms move slowly northward as they trek westward. Eventually they start moving more north than west and after reaching about 30 degrees north get caught up in the westerlies and begin trucking off to the northeast. Here they find themselves caught over colder waters and are slowly starved of their latent heat source. The storms gradually weaken over time and eventually fill in and dissipate. The storms can often last many days over cold water mostly because it takes a long time to wind down that much angular momentum. A lot of these storms actually develop a cold core in their centers making a transition from a warm core hurricane to a cold core mid-latitude system. Exactly what is going on in this process is not well understood. These transitional lows can often wreak as much havoc as their warm core parents as they reach land with high winds and very heavy rain.
By far the most interesting way for a hurricane to end its existence is if it makes landfall. Why is land the enemy of Hurricanes? Check all that apply.
A multitude of things happen as the storm reaches land. First the outer rain bands begin to feel the effects of the increase friction due to land. This increased friction causes greater inward turning of the wind and thus greater inflow into the bands and greater convection. The bands come ashore with heavy rains and gusty winds, the first precursor of the tempest to come. Well, actually high level cirrus blowing off the tops of the thunderstorms is the first sign, it is a little less noticable and before that there are often no clouds at all because of the subsidence surrounding the hurricane. As the hurricane itself comes ashore it too begins to feel the effects of friction, which often produces large complexes of violent supercells on the right front quadrant of the storm where winds moving onshore are forced to converge at a greater rate. Over the ocean this new intense convection would strengthen the storm, but over land with the loss of its surface heat source to continue to stoke the fires it is but a mere bump in the hurricane's life. Trapped over land away from its energy source the hurricane rapidly loses strength and begins to fill in. Contrary to what you may think it is not the friction of land that kills the hurricane or forces it to wind down and fill. It is the loss of latent heat to keep the center warm and pressure low. You might conjecture a warm swamp land could keep the storm going, but this is not the case. Land does not allow heat to penetrate as deeply into it as water does. The hurricane rapidly steals any heat that may be available and unlike the ocean the land can not continue to supply the hurricane with heat and without heat the hurricane is doomed.
Damage by landfalling hurricanes can be extensive, but usually the winds play a significantly smaller role than the storm surge, an effect that will be covered later. Some hurricanes spawn tornadoes, from what looks to be individual supercells and associated vortices that form in the circulation, but most wind damage comes from the storm winds produced by the primary circulation. Most damage occurs on the right side of the storm where winds coming off the ocean have been least affected by friction and where the winds are reinforced by the motion of the storm. On the left side of the storm winds have weakend greatly due to friction and the storm's motion subtracts from their effects. Dr. McGuirk jokingly refers to these as the "dirty" and "clean" sides of the hurricane respectively. Below are some figures depicting what we have just described.
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