 Throughout April 18th and April 20th, the southern states were slammed with a severe weather outbreak. A severe weather outbreak is classified as a weather system or combination of weather systems that produces multiple severe thunderstorms in a region over a continuous span of time.
Starting on Thursday afternoon, parts of Mississippi and Louisiana were under flash flood, severe thunderstorm, and tornado warnings as fierce thunderstorms rolled through the region. After tornadoes left a trail of destruction in Mississippi on Thursday, Mississippi Governor Phil Bryant declared a state of emergency on Friday afternoon. There was a report of one tornado hitting just outside of Jackson, Mississippi, in Clinton which left cars scattered around a Walmart parking lot. As the storms moved east, winds and warnings increased. Wind gusts reached 81 mph in Wears Valley, Tennessee and another tornado touched down in Franklin County, Virginia, which was classified as an EF-3. More tornados touched down in multiple other places, but needed to be confirmed first. A tornado has to be confirmed by an official from the National Weather Service through surveying because there is currently not a definite method for a meteorologist to tell if a tornado has touched ground. Officials take aerial photos to see if they can find a definitive path of the tornado They also check the ground to see which direction debris fell. Storms continued into Friday night, leaving over 215,000 people without power. With strong winds associated with these powerful storms, travel delays were reported in airports along the east coast, with nearly 4,000 delays and over 1,000 cancellations according to flightaware.com. Make sure to listen to the National Weather Service for warnings and watches that are issued in times like these to stay safe. To learn more about this and other severe weather topics around the globe, be sure to click www.globalweatherclimatecenter.com/severe-weather-topics! (Credit: NWS, and Weather.com) ©2019 Weather Forecaster Allison Finch
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The United States is one of the locations where a high frequency of tornadoes strike annually in the world. Tornadic activity happens in the United States due to the warm air from the Gulf of Mexico interacting with any frontal system that comes off of the Rocky Mountains. A common conception is that people tend to think that the majority of tornadoes form in the Great Plains of the United States, but there is a second “alley” that is catching the attention of people: Dixie Alley. Dixie Alley is found in the Southeast part of the United States and includes the following states: Louisiana, Arkansas, Mississippi, Alabama, Georgia, and Tennessee. This region is geographically different and has more diverse landscapes than the Great Plains. The following are a few factors as to why a higher count of tornadoes develop in Dixie Alley: the topography of the land, the type of supercells, in particular, the high precipitation supercell, the two seasonal peaks of tornadoes due to the movement of the jet stream in the spring and fall, when tornadoes strike and the types of homes that people live in all contribute to this pattern. The land in the Southeast is covered by trees, making it more difficult to see an oncoming tornado. Unlike the Great Plains with miles upon miles of prairie grass for all to see, the trees cut down on one’s ability to see tornadoes approaching from far away. The Southeast is relatively flat, but there are some hills and plateaus that one has to consider when trying to forecast the risk for severe weather. These hills and plateaus can cause a system to become stationary, causing more threats than just tornadoes. There are also major water sources that can fuel a system as well. The Gulf of Mexico feeds a constant supply of warm, moist air to the Southeastern United States, and numerous large bodies of water that can affect the storm.  The most frequent type of supercell is a High Precipitation Supercell. A High Precipitation Supercell is a supercell thunderstorm that has a lot of precipitation associated with it. While rain reduces the chances of a drought, it often obscures the tornado. This creates a rain-wrapped tornado, which cannot be spotted by storm spotters and storm chasers unless they are unfortunate enough to be caught in this area of a supercell. This area where a possible tornado could be is called the bear’s cage, and very few storm chasers want to end up in this area. Radars as well can struggle with picking up a tornado in a high precipitation supercell because of the precipitation obscuring and scattering the signal. Radar technology has improved since its invention, but when the scans only update every five minutes, these scans may not be able to catch every tornado that touches the ground.  By looking at the graph above, the time of day that these tornadoes strike is usually after the sun has gone down, taking away a vital way of spotting tornadoes. This leads to a problem because storm chasers and storm spotters cannot be as effective due to the lack of sunlight illuminating features of the storm that can lead to one to think that there is a chance of tornadoes forming. Plus, at night, people are sleeping and are unable to receive information from multiple sources. As a result, many of the reports of nocturnal tornadoes comes from looking at radar signatures formed by the supercell in question.
The time of year matters as well when a tornado strikes. The Southeast experiences two different annual peaks of tornadic activity because of the movement of the jet stream. As it moves down and up according to the season, it adds another piece of instability into the atmosphere. If the winds are in a different direction at the surface than aloft, then wind shear is present. These two peaks correlate to the Spring and Fall seasons and they occur in April and November. However, these two peaks do not limit the months that tornadoes can occur. They can occur year-round whenever there is a chance of severe weather with the right ingredients. Finally, where people live makes a major difference as well. There are more trailer parks in portions of the Southeast, and these homes are not made to withstand the high force winds that a tornado can bring. This statement was unfortunately proven correct when an EF-4 tornado struck the town of Beauregard, Alabama on March 3rd, 2019. The people that also live in the Southeast may not have adequate access to a tornado shelter or may not be within hearing distance of the sirens. The sirens are not meant to be heard inside, so if someone is inside a building, they may not know what is coming. There are other ways of receiving the information, such as a NOAA weather radio, but some people may not even have that. Dixie Alley is a second area in the United States for frequent tornadoes to strike. Although it is getting easier to detect when they are coming, their impacts are well known. From where and when they strike, to how people are warned, these tornadoes can often turn into significant tornadoes, forever changing the lives of those who have survived them. To Learn More About Severe Weather, make sure to check out https://www.globalweatherclimatecenter.com/severe-weather-topics ! Sources Cited: https://www.ncdc.noaa.gov/climate-information/extreme-events/us-tornado-climatology/trends https://ssl.c.photoshelter.com/img-get/I0000xgScCZjXlNs/s/860/688/wsi-stm017.jpg ©2019 Weather Forecaster Shannon Sullivan One of the biggest tornado myths out there is that tornadoes do not hit big cities. When we hear about tornadoes, we typically see them form over rural and suburban areas. What it actually comes down to is landmass. Because the United States is more country than City. In fact, only 3 percent of the entire land area in the United States is categorized as urban. It is pretty much throwing darts at a dartboard, you aren't going to hit the middle every time. Realistically, tornadoes can happen anywhere at anytime.  Today marks the 8th anniversary of the historic 2011 super tornado outbreak. It is now the largest tornado outbreak in U.S history as there were 362 tornadoes confirmed in just a 4 day time span. One of the tornadoes in this outbreak was the violent EF-4 tornado that struck Tuscaloosa and Birmingham, Alabama. This devastating tornado was 1.5 miles wide as it tore through Tuscaloosa and had estimated winds of 190 mph. It then would go on and cause destruction in Birmingham, AL where the National Weather Service found EF-4 damage. In total, this tornado was on the ground for an hour and a half and for a staggering 80.6 miles. Overall, the tornado killed 64 people and caused up to 2.2 billion dollars in damage. It was the costliest tornado in U.S history before the EF-5 Joplin tornado took the top spot in May of that same year.  Next, we a trip from Dixie Alley to the Southern Plains. On May 3rd, 1999, a supercell produced 14 tornadoes in a 3.5 hour span. One of them was the powerful and violent EF-5 tornadoes that stuck Moore, Oklahoma and Oklahoma City. The tornado first entered the western portions of Moore and produced high-end EF-4 to low-end EF-5 damage. The tornado continued to move to the northeast and then entered the southern areas in Oklahoma City where it continued to produce EF-4 damage. This tornado was so powerful, that an 18 ton freight car was tossed 3/4 of a mile across an open field. This tornado killed 56 people and injured. A total of 1800 homes were destroyed and 2500 were damaged resulting in 1 billion dollars in damage.  And finally, the last significant tornado to strike the Stateline area (Illinois/Wisconsin border) that many people might not known about was the F4 Belvidere tornado on April 21st, 1967. A 26.6 mile monster that first touched down a little before 4 PM in the afternoon a few miles southeast of Cherry Valley, IL. It then continued to move northeast and would enter the city of Belvidere right around the time students were getting on the buses to head home. One hundred twenty seven homes were destroyed, and hundreds more were damaged. The most notable and horrific part of this tornado was the mayhem at the Belvidere High School. Buses had already picked up the elementary school children and were loading the high school students when the tornado struck. In fact, 13 of the 24 fatalities occurred at the high school.  The lesson to take from this, urban areas are just as vulnerable to tornadoes as rural areas are. Whether you live downtown in a metro city, or on the outskirts of a big city, you still need to have a severe weather plan on hand in case severe weather or even a tornado rolls into your area. Have your safe place ready to go and make sure you have a way to receive watches and warnings, whether that be a weather radio, your cell phone, or tuning in to your local TV stations.
To learn more about this and other severe weather topics around the globe, be sure to click www.globalweatherclimatecenter.com/severe-weather-topics! ©2019 Meteorologist Joey Marino |
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