Flash floods, rapid rises in water levels with high flow velocities – can occur in a matter of seconds. Make sure you monitor weather service announcements during big storms in case of a flash flood warning. If you live in a region that is prone to flash floods, make sure you have a map to the quickest region of high ground. With these figures readily available, weather services can provide predictions and early warnings to give inhabitants of the region time to move to higher ground. Flash flood guidance is the amount of rainfall for a given duration necessary to produce flash flooding.
The forecast center for your region calculates flash flood guidance for all the bodies of water in the area. Areas with a high risk of flash floods (such as the land surrounding large dams) often have warning systems in place to help alert the population in advance of a flood. Dry riverbeds can channel water long distances and create dangerous flood waves, due to the ground being too dry to quickly absorb the water and the lack of plant life to slow the water’s course. Even deserts are not immune to flash flooding. A similar situation occurred in Rapid City, South Dakota, in 1972 when 237 people were killed.
In mountainous regions the rainfall can run down a steep mountain and pick up so much speed that it becomes a dangerous wave moving too fast for people to escape. The roofs, sidewalks, and roads of a city create dangerous amounts of runoff water during big storms, and this runoff can easily become a flash flood if an adequate storm sewer system is not in place. Urbanization is also an important cause of flash floods. Factors such as rainfall intensity and duration, as well as regional topography, can all contribute to a flash flood situation.
If a new mesocyclone develops, the cycle may begin again, generating a new tornado, and in some cases there may be 2 or more funnels touching the earth at any one time. As the first mesocyclone and associated tornado dissipate, the storm’s inflow is concentrated into a new area closer to the center of the storm. As the tornado enters the dissipating stage, its associated mesocyclone often weakens as well, as the rear flank downdraft cuts off the air flow powering it.
As the mesocyclone nears the ground, a visible funnel appears from the base of the storm clouds. This downdraft accelerates as it approaches the ground, and drags the rotating mesocyclone towards the ground with it. As rainfall in the storm increases, it drags with it an area of quickly descending air known as the rear flank downdraft. The life cycle of a tornado begins when a strong thunderstorm develops a rotating mesocyclone high up in the atmosphere.
Tornadoes have been observed on every continent on earth except Antarctica, the majority the world’s tornadoes occur in the United States and in particular Tornado Alley. Some tornadoes can have winds of more than 280mph, can be more than a mile across, and stay on the ground for tens of miles. Most tornadoes have winds of 100mph or less, are approximately 90 meters wide, and travel a few miles before fizzling out.
Tornadoes typically have a visible funnel, with the narrow end touching the surface of the earth. Tornadoes are defined as an aggressively rotating column of air which is in contact with both a cloud base and the earth.
Those caught up in a hurricane know only too well when the eye is above them, and although it can buy a bit of valuable time to move, help, or rescue victims, many often describe this moment as a deafening silence. There is an eerie silence within this eye and often clear blue skies and light winds can be usual. A characteristic of a hurricane is the eye and the eye of the storm can be anything from 4 to 25 miles in diameter. The condensation releases latent heat and this heat then powers the hurricane.
Moisture then condenses, clouds are formed, and the rains begin. As this warm air rises around the storms center, it cools. Therefore, the perfect conditions for a hurricane to form are basically warm water and humid air. Hurricanes occur over oceans where the water is 27°C (80°F) or above, and the air has to also be extremely humid and thick. Katrina, by the way, sustained winds of up to 140 mph.
In order to reach hurricane status it has to have sustainable winds exceeding 74 miles per hour. But a hurricane is not just any tropical storm. Well, without going into to much meteorological detail, a hurricane is basically a tropical storm so therefore can only be found in the tropics, namely the Southern Atlantic Ocean, Caribbean Sea, Gulf of Mexico, and in the eastern Pacific Ocean. So just what are hurricanes and why do they occur in certain parts of the world and not others? It’s not the purpose of this short piece to look for someone or something to blame, as lessons have probably already been learnt from the powers that be, but I just hope that the United States governments and responsible departments do everything in their power to ensure such a catastrophe, as was caused by Katrina, never happens again.
Hurricanes can be highly destructive to say the least. Depending which part of the world you come, from you may here about natures ravaging winds being called tropical cyclones or typhoons, but where I come from in the USA, we know them as hurricanes.
Through the use of the various NOAA (National Oceanic and Atmospheric Administration’s) weather radars, we are able to stay informed about current and future weather conditions. The role of the NOAA National Weather Service is to help predict the weather and warn us of any danger such as hurricanes or flash floods. Since there is such a variety of colors, you will have to find a chart either online or in a textbook that can help you. The different colors that are visible on the image represent rainfall rates.
The radar images on their site are updated every thirty minutes. The National Weather Service has a very comprehensive website that will help you learn more about the NOAA weather radars. Storm-total precipitation is an image that represents how much rainfall or precipitation is determined for a storm. One-hour precipitation reports help establish rainfall amount and assess any flash food warnings. This helps us understand a given storm’s general makeup and its strength.
NOAA weather radars use NEXRAD or Next Generation Radar to gather data that will help us understand current and future weather conditions. There are a series of NOAA weather radars that help them do their job. They track weather and climate trends as well as current conditions. The NOAA (National Oceanic and Atmospheric Administration) National Weather Service is responsible for monitoring the weather throughout the country. Following the weather patterns can help enhance the quality of our own lives.
So much of our lives are dependent on the weather. Even if you are not an expert, it is still beneficial to learn how to read the National Weather Service radar imagery. There are plenty of resources both in books and online that can help. Satellite images are available to view online, but you may need some guidance when interpreting them. Such a large occurrence of radars allows for more accurate readings.
Experts whose specialty is to interpret the data monitor the National Weather Service radars. From the radar images, data is interpreted and updated constantly to keep all information current. To do so, there is a large network of National Weather Service radars that help gather this information. The National Weather Service is responsible for keeping track of the weather patterns, trends and current conditions in the United States.
Composite reflectivity is often compared with base reflectivity. From this, you can spot any precipitation, understand and measure a storm’s makeup, establish whether or not a hailstorm is possible and better understand the atmosphere. Base reflectivity measures the strength of the signal that is reflected back to the antennae. These are base reflectivity, composite reflectivity, one-hour precipitation and storm total precipitation. There are four types of images that come about because of this technology.
Some areas have a higher concentration of National Weather Service Radars than others, which probably has to do with the conditions of a given area. There is also one above Puerto Rico and one above Guam. National Weather Service Radars are located in each state except all the New England states that are small and can be serviced by the same handful of radars. All these images make up the full picture of storm and weather predictions.
They are base reflectivity, composite reflectivity, one-hour total rainfall and storm total rainfall. There are generally four types of data and images that are produced from these radars. The National Weather Service radars use NEXROD, or Next Generation Radar technology and Doppler radars. All these avenues serve to help us understand the weather conditions and patterns in our own backyards. They then publish some of their images and findings on their website and in other media, such as radio and television.
