Distribution Of Tornadoes Research Articles

Effects of Anthropogenic Climate Change on the Occurrence of Supercellular Tornadoes in the USA

The United States of America (USA) experiences the most tornadoes of any nation in the world, with these extreme weather events causing many deaths and billions of dollars of damage each year. With the recent warming of the climate due to human activity, it is likely that the occurrence of USA tornadoes will be affected. However, exactly how the spatial and temporal distribution of tornadoes in the USA will be affected by climate change is still an area of active research. The trends in the literature show that as the climate has warmed, there has been an observed clustering of USA tornadoes onto fewer, more active tornado days, as well as an eastward movement of the average centre of USA tornado activity. This review shows that these observed changes could be explained by shifts in environmental parameters related to tornado formation due to anthropogenic climate change. This research will allow for better tornado preparedness and prediction in tornado-affected areas as the climate warms. Future research may focus on more precisely modelling the impacts of global warming on USA tornado occurrence by using higher-resolution climate models.

Characteristics of Extratropical Cyclones That Cause Tornadoes in Italy: A Preliminary Study

Characteristics of extratropical cyclones that cause tornadoes in Italy are investigated. Tornadoes between 2007 and 2016 are analyzed, and statistical analysis of the associated cyclone structures and environments is performed using the JRA-55 reanalysis. Tornadoes are distributed sporadically around the cyclone location within a window of 10° × 10°. The difference in the cyclone tracks partially explains the seasonal variability in the distribution of tornadoes. The highest number of tornadoes occur south of the cyclone centers, mainly in the warm sector, while a few are observed along the cold front. Composite mesoscale parameters are examined to identify the environmental conditions associated with tornadoes in different seasons. Potential instability is favorable to tornado development in autumn. The highest convective available potential energy (CAPE) in this season is associated with relatively high-temperature and humidity at low-levels, mainly due to the strong evaporation over the warm Mediterranean Sea. Upper-level potential vorticity (PV) anomalies and the associated cold air reduce the static stability above the cyclone center, mainly in spring and winter. On average, the values of CAPE are lower than for US tornadoes and comparable with those occurring in Japan, while storm relative helicity (SREH) is comparable with US tornadoes and higher than Japanese tornadoes, indicating that the environmental conditions for Italian tornadoes have peculiar characteristics. Overall, the conditions emerging in this study are close to the high-shear, low-CAPE environments typical of cool-season tornadoes in the Southeastern US.

Seasonal Frequency and Spatial Distribution of Tornadoes in the United States and Their Relationship to the El Niño/Southern Oscillation

Tornadoes are extremely destructive phenomena that can cause tremendous loss of life and catastrophic damage to the natural and built landscape. Their frequency of occurrence varies notably from season to season and from year to year. Tornado variability in the United States and its covariates have been the focus of numerous recent studies. The El Niño/Southern Oscillation has emerged as a covariate with some predictive skill, but most recent studies have focused on its link to tornado activity in boreal winter and spring. This study provides an analysis of the relationship between tornado activity in the United States and the El Niño/Southern Oscillation in all four seasons and for multiple regions. In doing so, this study illustrates that the relationship between tornado activity and the El Niño/Southern Oscillation is seasonally and regionally dependent. The relationship in winter and spring is confirmed but only in the Southeast and Midwest regions. Furthermore, the relationship is stronger in winter than in spring in the Southeast and Midwest. The ability of the El Niño/Southern Oscillation to predict the odds of below- or above-normal tornado activity is also greatest in winter in these regions. There is little evidence of a relationship between tornado frequency and the El Niño/Southern Oscillation in summer and fall, with the exception of a positive correlation between the El Niño/Southern Oscillation in spring and tornado frequency in summer. Key Words: El Niño/Southern Oscillation, seasonal tornado frequency, spatial distribution of tornadoes, United States.

Spatiotemporal variability of tornadoes in the Czech Lands, 1801–2017

Tornadoes are severe, small-scale weather phenomena that may cause loss of human lives and give rise to great material damage on a local (regional) scale. Because of their limited spatial extent, they are usually seldom recorded in the standard network of meteorological stations and corresponding information has therefore to be gathered from various documentary sources (narrative sources, taxation data, newspapers, special reports, etc.). Qualitative description of such events over the territory of the Czech Lands (recently, the Czech Republic) has facilitated the creation of a database of tornadoes and the classification of them as “proven” or “probable” for the 1801–2017 period. A total of 367 tornadoes and 299 days with tornado have been detected. The temporal distribution of tornadoes is very non-regular and reflects the availability of documentary sources inspected and general public interest in them. Decades in which their frequency was highest were found in 2001–2010, 1931–1940 and 1921–1930. They occurred mainly in the summer months (70.3%) with a July maximum (28.1%). Moderate tornadoes (F1 on the Fujita scale) were the most frequent (41.7%). Uprooted fruit trees and damage to hop gardens and vineyards, together with considerable damage to structures or buildings destroyed, constituted the most common types of damage. At least 17 people were killed and more than 127 people injured during the 367 documented tornadoes. Seventeen tornadoes with F2–F3 and seven with F3 are listed and briefly characterised. Three F3 events from 11 May 1910, 20 April 1950 and 9 June 2004 are described in more detail. Results related to the spatiotemporal variability of tornadoes in the Czech Lands are further discussed from the viewpoint of data uncertainty and the broader European context.

The spatial distribution of tornadoes and high wind impacts associated with inland-moving tropical cyclones in the southeastern United States

The southeastern United States is routinely hit by tropical cyclones (TC). As TC track inland and dissipate their inland impacts can be substantial. This study examined the spatial patterns of societal impacts associated with tornadoes and high winds with 31 inland-moving TC that made landfall from 1985 to 2008. Hourly weather information was collected from all available first-order weather stations affected by each storm, as well as tropical cyclone preliminary reports issued from the National Hurricane Center. Societal impacts were identified through selected newspapers across the region and the National Climatic Data Center’s Storm Data. Geographic Information System (GIS) software was employed to make geometric measurements of the distance and direction of the impacts relative to storm center. From these measurements, the spatial distribution of the societal and meteorological impacts was plotted relative to the track (e.g., left vs. right) and location (forward vs. rear sector) of the cyclone center. Various tropical cyclone attributes, including size, strength, and forward speed of movement were then related to the occurrence of different impacts and their location relative to the cyclone track. The majority of tropical cyclone tornado and high wind impacts occur in the right-forward sector of the tropical cyclone. However, many TC produce impacts that occur in other sectors far from the center of circulation. These abnormalities are associated in many cases with interactions between the tropical cyclone circulation, topography, peripheral dry air, and extratropical synoptic weather features.

Tornado activity in Greece within the 20th century

Abstract. Tornado activity is associated with extreme convective weather which can cause extended damage and even in some cases the loss of life. The complex inland terrain of Greece along with the Ionian Sea at the west and the Aegean Sea at the east appear to be a favorable area for fury phenomena such as tornadoes, waterspouts and funnel clouds. In this study, the spatial and temporal variability of tornado activity in Greece for the period 1900–1999 are presented. The spatial distribution of tornadoes, waterspouts and funnel clouds reveals the vulnerability of specific geographical areas, such as the west Greece and the south Aegean Sea. As far as the intra annual variability is concerned, the maximum of tornado activity dominates within the cold period of the year (October–March) while according to the daily distribution, tornadoes happen frequently during the warm hours of the day. It is remarkable to mention that in Greece, within the 20th century, the tornado activity caused the loss of 4 lifes, the injury of 40 people and numerous damages on human constructions and cultivations.

An Empirical Method of Forecasting Tornado Development

The frequency distribution of tornadoes in the United States is discussed briefly and an empirical method of forecasting these and allied severe local storms is described. It is shown that the formation of such storms can be forecast by evaluating certain empirical criteria related to the stability of the air column, the horizontal and vertical distributions of the moisture content and the wind. A typical tornado development is discussed from a synoptic point of view. An unusual situation and the verification of 35 experimental forecasts are briefly described.

TORNADOES IN ARKANSAS, 1879–1926

Abstract SYNOPSIS The article presents three tables: One showing the place, date, and certain statistics regarding 225 tornadoes which occurred in Arkansas from 1879 to 1926; one showing the distribution of tornadoes by months and years; one showing the number of tornadoes by months from 1908 to 1926, the number of thunderstorms in Little Rock for the same period, and a comparison of tornadoes in Arkansas and thunderstorms at Little Rock. A chart showing the distribution of tornadoes over the State is given with arrows showing the direction of tornadoes at Fort Smith, Little Rock, Heber Springs, and Hot Springs. The chart and tables are discussed, also some of the larger features of topography and their probable effect on the courses and distribution of tornadoes. Ibis pointed out that tornadoes usually form in the southeastern portion of the LOW and move northeast-ward; and reasons are given for the movement of some tornadoes in other directions and for the occurrence of tornado families.