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Tracking Hurricanes, Recording Hurricanes, And Just What Does El Nino Have To Do With It?The subject of Hurricanes is a big one - in fact it has spread over five pages of this website. Part 1 - Hurricane Basics was concerned mainly with definitions and the way hurricanes are named and classified.
Part 4, More Hurricane Resources , lists some of the hurricane information, such as DVDs, books and posters, that don't require an internet connection to be enjoyed. And Part 5 - Ever wondered what it's like to stay on as a hurricane passes overhead? Check out Hurricane Safety for an account of sitting through Hurricane Wilma as it struck Southern Florida in October 2005.
But back to Part 2 - this article. Here we'll look at how hurricanes move, why their paths differ from one storm to the next, and how to use your home weather station and other resources when a hurricane is on its way.
Hurricane Tracking
Even though a tropical depression may have intensified to a
hurricane, its future is by no means clear. A patch of
drier air at mid levels, strong opposing winds at height,
or an area of cooler water can cause it to fade away.
Hurricane Anna, 1964 - the first
If it does persist, its future path is difficult to predict. The general trend in the North Atlantic hurricane area is for hurricanes to move to the west with a tendency to veer to the north.
The main controlling feature is an east-west axis of high pressure called the subtropical ridge which exists to the north of the hurricane zone. The tendency of many hurricanes is to work their way around this ridge, moving north around its western edge and often curving back to the east.
The strength of the ridge plays a significant part in determining whether the hurricane continues west across the Caribbean to Mexico and southern Texas, swings around towards Florida, or curves further towards the north east coast of the USA, even heading out to sea.
Study of the overall weather system allows meteorologists to predict a hurricane's path and likely fate. But hurricanes can last for weeks, and long range weather forecasts are not the most precise tool in a forecaster's arsenal. Consequently initial predictions can be expected to change as the hurricane carves its path across the area, and they need to be updated continuously.
Once a hurricane crosses the coast it loses its source of energy from warm sea waters, and begins to degenerate. Winds drop rapidly, and, depending on location in relation to the centre, rain may also cease quite quickly.
However, the depression often has some life left in it, and depending on its path, its location, and other weather conditions, it may reform if it returns to warm waters.
Otherwise it may become a rain depression and cause major inland flooding, or it may contribute to thunderstorm and tornado development, particularly in southern states.
Observing Hurricanes
As usual with severe weather, your own safety should be your first and main consideration. If you live in a low lying coastal area in a hurricane's path your best move is to leave, with plenty of time to spare. In the more severe hurricanes (Category 4 or 5) you can expect a storm surge in excess of 12 feet (3.7m). This will begin to cause flooding well in advance of the storm center, and could cut your escape route. A reliable Weather Radio tuned to local warnings must be regarded as essential.
So with the sea rising, the rain falling, and the winds horizontal, the best place to be is somewhere else.
Apart from anything else, very few weather stations, whether
home or official, can continue working through a severe
hurricane. Damage from strong winds and flying debris is
common, and power is almost always lost soon after wind
speeds reach hurricane strength. So even if your
anemometer keeps spinning at record rates, without power
you'll have no records to confirm it.
Landfall of Hurricane Georges,
In safer circumstances, your home weather station will provide very interesting records of one of weather's major events. If you can reinforce the data with personal observations, photos, or videos. Changes in cloud types, and their direction of movement, are certainly worth noting.
You will also be able to keep track of a hurricane's position through satellite images, and, once in range, through radar.
Which leads to remote tracking and follow up.
When a hurricane is in the area it can easily be tracked by keeping up with watches and warnings on radio, TV, and the internet. The National Hurricane Center has blank tracking charts of the Caribbean/Western Atlantic area available as a pdf file.
Satellite imagery is also available, plus other tracking information. Radar may be hard to find until hurricanes are close to the US coast (or Puerto Rico).
And after the event is over, you can find a complete and detailed of the history of the hurricane, from its causes to its final disappearance, in the NHC's excellent archive section.
Hurricanes and El Nino
Since the causes and processes of El Nino/La Nina events began to be understood during the early 1980s, El Nino has been blamed for most occurrences of severe or unusual weather, crop failures, stock market collapses and more.
The blame is not always well directed, but these world wide climatic oscillations do have significant effects on weather, particularly in Tropical and nearby areas.
But since all El Nino events differ in some respects from each other, the responses of weather to an El Nino will not always be consistent or predictable.
However, in the case of North Atlantic hurricanes there is a clear tendency for fewer hurricanes in an El Nino year. There is also a tendency for the hurricane paths to be further to the east, with fewer landfalls on continental USA. In contrast, a La Nina year may be expected to result in more hurricanes.
More information on El Nino will be available in a future article.
More information can be found among the Severe Weather articles, the links at the top of this page, and you'll find heaps of other great resources -DVDs, videos, books, posters etc - at More Hurricane Resources This link will take you back to the Top, or, when you're ready, here's how to return to the Home page.
Click Here For Your Free 20 Page Report on Solving
Last update 12/12/2006
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