|Part of a series on|
In meteorology, a heat burst is a rare atmospheric phenomenon characterized by a sudden, localized increase in air temperature near the Earth's surface. Heat bursts typically occur during night-time and are associated with decaying thunderstorms.  They are also characterized by extremely dry air and are sometimes associated with very strong, even damaging, winds.
Although the phenomenon is not fully understood, the event is thought to occur when rain evaporates (virga) into a parcel of cold, dry air high in the atmosphere, making the air denser than its surroundings.  The parcel descends rapidly, warming due to compression, overshoots its equilibrium level, and reaches the surface, similar to a downburst. 
Recorded temperatures during heat bursts have reached well above 40 °C (104 °F ), sometimes rising by 10 °C (18 °F) or more within only a few minutes.
In general, heat bursts occur during the late spring and summer seasons. During these times, air-mass thunderstorms tend to generate due to daytime heating and lose their main energy during the evening hours.  Due to the potential temperature increase, heat bursts normally occur at night, though they have also been recorded during the daytime. Heat bursts can vary widely in duration, from a couple of minutes to several hours. The phenomenon is usually accompanied by strong gusty winds, extreme temperature changes, and an extreme decrease in humidity. They may occur near the end of a weakening thunderstorm cluster. Dry air and a low-level temperature inversion may also be present during the storm. 
Heat bursts are thought to be caused by a mechanism similar to that of downbursts. As the thunderstorm starts to dissipate, the layer of clouds starts to rise. After the clouds have risen, a rain-cooled layer remains. The cluster shoots a burst of unsaturated air down towards the ground. In doing so, the system loses all of its updraft-related fuel.  The raindrops begin to evaporate into dry air, which reinforces the effects of the heat burst (evaporation cools the air, increasing its density). As the unsaturated air descends into lower levels of the atmosphere, the air pressure increases. The descending air parcel warms at the dry adiabatic lapse rate of approximately 10 °C per 1000 meters (5.5 °F per 1000 feet) of descent. The warm air from the cluster replaces the cool air on the ground. The effect is similar to someone blowing down on a puddle of water.
On 4 March 1990, the National Weather Service in Goodland, Kansas, detected a system that had weakened, containing light rain showers and snow showers. It was followed by gusty winds and a temperature increase. The detection proved that heat bursts can occur in both summer months and winter months, and also that a weakening thunderstorm was not necessary for the development of a heat burst.
The first step in forecasting and preparing for heat bursts is recognizing the events that precede them. Rain from a high convection cloud falls below cloud level and evaporates, cooling the air. Air parcels that are cooler than the surrounding environment descend in altitude. Lastly, temperature conversion mixed with a downdraft momentum continues downward until the air reaches the ground. The air parcels then become warmer than their environment.
McPherson, Lane, Crawford, and McPherson Jr. researched the heat burst system at the Oklahoma Mesonet, which is owned by both the University of Oklahoma and Oklahoma State University. The purpose of their research was to discover any technological benefits and challenges in detecting heat bursts, to document the time of day and year at which heat bursts are most likely to occur, and to research the topography of where heat bursts are most likely to occur in Oklahoma.
Scientists and meteorologists use archived data to manually study data that detected 390 potential heat burst days during a fifteen-year period. In studying the archived data, they observed that 58% of the potential days had dry line passages, frontal passages, or a temperature change due to an increase in solar radiation in the hours of the morning or a daytime precipitation weather system.
By studying the archived data, scientists have the ability to determine the beginning, peak, and end of heat burst conditions. The peak of heat burst conditions is the maximum observed temperature. The beginning of a heat burst is the time during which the air temperature increases without decreasing until after the peak; the end of a heat burst is when the system ceases to affect the temperature and dew point of the area.
In addition to researching the life cycle and characteristics of heat bursts, a group of scientists concluded that the topography of Oklahoma coincided with the change in atmospheric moisture between northwest and southeast Oklahoma. An increase in convection normally occurs over the High Plains of the United States during the late spring and summer. They also concluded that a higher increase in convection develops if a mid-tropospheric lifting mechanism interacts with an elevated moist layer. 
|Date||Location||Temperature °F/°C (Initial)||Temperature °F/°C (Final)||Difference (Max)||Reference(s)|
|11 October 2022||Durban, South Africa||88°F (31°C)||100°F (38°C)||12°F (7°C)|||
|14 June 2022||Tracy, Minnesota||80 °F (27 °C)||93 °F (34 °C)||13°F|||
|21 May 2022||Beja, Portugal||73.2 °F (22.9 °C)||92.1 °F (33.4 °C)||18.9°F|||
|20 May 2022||Greenville, North Carolina||73 °F (23 °C)||86 °F (30 °C)||13°F|||
|22 June 2021||Littleton, Colorado||72 °F (22 °C)||88 °F (31 °C)||16°F|| |
|13 June 2021||Friona, Texas||70 °F (21 °C)||88.1 °F (31.2 °C)||18°F||  |
|4 June 2020||Edmond, Oklahoma||—||97 °F (36 °C)||—|||
|25 July 2019||Donna Nook, Lincolnshire, England||71.6 °F (22.0 °C)||89.6 °F (32.0 °C)||18°F|||
|16 July 2017||Chicago, Illinois||72 °F (22 °C)||79 °F (26 °C)||7°F||  |
|16 July 2017||Chicago, Illinois||73 °F (23 °C)||81 °F (27 °C)||8°F|
|July 2016 [lower-alpha 1]||Hobart, Oklahoma||80.6 °F (27.0 °C)||105.7 °F (40.9 °C)||25.2°F|||
|July 2014||Calgary, Alberta||79 °F (26 °C)||84 °F (29 °C)||5°F||   |
|31 July 2014||Calgary, Alberta||79 °F (26 °C)||84 °F (29 °C)||5°F|
|January 2014||Melbourne, Victoria||85.8 °F (29.9 °C)||102 °F (39 °C)||16.2°F||  |
|75.6 °F (24.2 °C)||90.5 °F (32.5 °C)||14.9°F|
|79.9 °F (26.6 °C)||92.5 °F (33.6 °C)||12.6°F|
|92.5 °F (33.6 °C)||97.5 °F (36.4 °C)||5°F|
|11 June 2013||Grand Island, Nebraska||74.2 °F (23.4 °C)||93.7 °F (34.3 °C)||19.5°F|||
|15 May 2013||Dane County, Wisconsin||—||—||10°F|||
|14 May 2013||South Dakota||58 °F (14 °C)||79 °F (26 °C)||21°F|||
|1 July 2012||Georgetown, South Carolina||79 °F (26 °C)||90 °F (32 °C)||11°F|||
|3 May 2012||Bussey, Iowa||74 °F (23 °C)||85 °F (29 °C)||11°F|| |
|29 April 2012||Torcy, Seine-et-Marne, France||56.1 °F (13.4 °C)||75 °F (24 °C)||18.9°F|||
|23 August 2011||Atlantic, Iowa||88 °F (31 °C)||102 °F (39 °C)||14°F||  |
|3 July 2011||Indianapolis, Indiana||—||—||15°F|||
|9 June 2011||Wichita, Kansas||85 °F (29 °C)||102 °F (39 °C)||17°F|||
|29 October 2009||Buenos Aires, Argentina||87.8 °F (31.0 °C)||94.2 °F (34.6 °C)||6.4°F|||
|26 April 2009||Delmarva Peninsula||68 °F (20 °C)||87 °F (31 °C)||19°F|||
|18 August 2008||Edmonton, Alberta||72 °F (22 °C)||88 °F (31 °C)||16°F||    |
|3 August 2008||Sioux Falls, South Dakota||70 °F (21 °C)||101 °F (38 °C)||31°F|||
|26 June 2008||Cozad, Nebraska||—||—||20°F|| |
|16 June 2008||Midland, Texas||71 °F (22 °C)||97 °F (36 °C)||26°F|| |
|25 May 2008||Emporia, Kansas||71 °F (22 °C)||91 °F (33 °C)||20°F|||
|16 July 2006||Canby, Minnesota||—||100 °F (38 °C)||—|||
|20 June 2006||Hastings, Nebraska||75 °F (24 °C)||94 °F (34 °C)||19°F|| |
|12 June 2004||Wichita Falls, Texas||83 °F (28 °C)||94 °F (34 °C)||11°F|| |
|May 1996||Chickasha, Oklahoma||87.6 °F (30.9 °C)||101.9 °F (38.8 °C)||14.3°F|||
|May 1996||Ninnekah, Oklahoma||87.9 °F (31.1 °C)||101.4 °F (38.6 °C)||13.5°F|
|2 July 1994||Barcelona, Spain||—||—||23°F|||
|August 1993||Barcelona, Spain||—||—||23 °F|
|15 June 1960||Kopperl, Texas||75 °F (24 °C)||100 °F (38 °C)||25 °F||Possible that temps rose to or above 140 °F (60 °C) as thermometers designed to detect such temperatures broke. |
A thunderstorm, also known as an electrical storm or a lightning storm, is a storm characterized by the presence of lightning and its acoustic effect on the Earth's atmosphere, known as thunder. Relatively weak thunderstorms are sometimes called thundershowers. Thunderstorms occur in a type of cloud known as a cumulonimbus. They are usually accompanied by strong winds and often produce heavy rain and sometimes snow, sleet, or hail, but some thunderstorms produce little precipitation or no precipitation at all. Thunderstorms may line up in a series or become a rainband, known as a squall line. Strong or severe thunderstorms include some of the most dangerous weather phenomena, including large hail, strong winds, and tornadoes. Some of the most persistent severe thunderstorms, known as supercells, rotate as do cyclones. While most thunderstorms move with the mean wind flow through the layer of the troposphere that they occupy, vertical wind shear sometimes causes a deviation in their course at a right angle to the wind shear direction.
Surface weather analysis is a special type of weather map that provides a view of weather elements over a geographical area at a specified time based on information from ground-based weather stations.
The National Weather Service (NWS) is an agency of the United States federal government that is tasked with providing weather forecasts, warnings of hazardous weather, and other weather-related products to organizations and the public for the purposes of protection, safety, and general information. It is a part of the National Oceanic and Atmospheric Administration (NOAA) branch of the Department of Commerce, and is headquartered in Silver Spring, Maryland, within the Washington metropolitan area. The agency was known as the United States Weather Bureau from 1890 until it adopted its current name in 1970.
A squall line, or more accurately a quasi-linear convective system (QLCS), is a line of thunderstorms, often forming along or ahead of a cold front. In the early 20th century, the term was used as a synonym for cold front. Linear thunderstorm structures often contain heavy precipitation, hail, frequent lightning, strong straight-line winds, and occasionally tornadoes or waterspouts. Particularly strong straight-line winds can occur where the linear structure forms into the shape of a bow echo. Tornadoes can occur along waves within a line echo wave pattern (LEWP), where mesoscale low-pressure areas are present. Some bow echoes can grow to become derechos as they move swiftly across a large area. On the back edge of the rainband associated with mature squall lines, a wake low can be present, on very rare occasions associated with a heat burst.
The climate of Chicago is classified as hot-summer humid continental. All four seasons are distinctly represented: Winters are cold and often see snow with below 0 Celsius temperatures and windchills, while summers are warm and humid with temperatures being hotter inland, spring and fall bring bouts of both cool and warm weather and fairly sunny skies. Annual precipitation in Chicago is moderate and relatively evenly distributed, the driest months being January and February and the wettest July and August. Chicago's weather is influenced during all four seasons by the nearby presence of Lake Michigan.
A weather front is a boundary separating air masses for which several characteristics differ, such as air density, wind, temperature, and humidity. Disturbed and unstable weather due to these differences often arises along the boundary. For instance, cold fronts can bring bands of thunderstorms and cumulonimbus precipitation or be preceded by squall lines, while warm fronts are usually preceded by stratiform precipitation and fog. In summer, subtler humidity gradients known as dry lines can trigger severe weather. Some fronts produce no precipitation and little cloudiness, although there is invariably always a wind shift.
A mesoscale convective system (MCS) is a complex of thunderstorms that becomes organized on a scale larger than the individual thunderstorms but smaller than extratropical cyclones, and normally persists for several hours or more. A mesoscale convective system's overall cloud and precipitation pattern may be round or linear in shape, and include weather systems such as tropical cyclones, squall lines, lake-effect snow events, polar lows, and mesoscale convective complexes (MCCs), and generally forms near weather fronts. The type that forms during the warm season over land has been noted across North and South America, Europe, and Asia, with a maximum in activity noted during the late afternoon and evening hours.
Severe weather is any dangerous meteorological phenomenon with the potential to cause damage, serious social disruption, or loss of human life. Types of severe weather phenomena vary, depending on the latitude, altitude, topography, and atmospheric conditions. High winds, hail, excessive precipitation, and wildfires are forms and effects of severe weather, as are thunderstorms, downbursts, tornadoes, waterspouts, tropical cyclones, and extratropical cyclones. Regional and seasonal severe weather phenomena include blizzards (snowstorms), ice storms, and duststorms. Extreme weather phenomena which cause extreme heat, cold, wetness or drought often will bring severe weather events. One of the principal effects of anthropogenic climate change is changes in severe and extreme weather patterns.
A wake low, or wake depression, is a mesoscale low-pressure area which trails the mesoscale high following a squall line. Due to the subsiding warm air associated with the system's formation, clearing skies are associated with the wake low. Once difficult to detect in surface weather observations due to their broad spacing, the formation of mesoscale weather station networks, or mesonets, has increased their detection. Severe weather, in the form of high winds, can be generated by the wake low when the pressure difference between the mesohigh preceding it and the wake low is intense enough. When the squall line is in the process of decay, heat bursts can be generated near the wake low. Once new thunderstorm activity along the squall line concludes, the wake low associated with it weakens in tandem.
The following is a glossary of tornado terms. It includes scientific as well as selected informal terminology.
This page documents notable tornadoes and tornado outbreaks worldwide in 2020. Strong and destructive tornadoes form most frequently in the United States, Argentina, Brazil, Bangladesh, and eastern India, but can occur almost anywhere under the right conditions. Tornadoes also develop occasionally in southern Canada during the Northern Hemisphere's summer and somewhat regularly at other times of the year across Europe, Asia, Argentina, Australia and New Zealand. Tornadic events are often accompanied by other forms of severe weather, including strong thunderstorms, strong winds, and hail.
During the afternoon and evening of April 22, 2020, an outbreak of discrete supercell thunderstorms across portions of Oklahoma, Texas, and Louisiana led to widespread severe weather, including multiple strong tornadoes. Two people were killed by a high-end EF2 that struck the town of Madill, Oklahoma, and three more were killed by an EF3 wedge tornado that moved through Onalaska, Texas. Dozens of others were injured as well. The event came to fruition as a trough progressed eastward across the United States, interacting with a moist and unstable environment. Tornado activity continued into Arkansas, Louisiana, Mississippi, Alabama, Florida, and Georgia overnight into the day on April 23.
This page documents notable tornadoes and tornado outbreaks worldwide in 2021. Strong and destructive tornadoes form most frequently in the United States, Argentina, Brazil, Bangladesh, and Eastern India, but can occur almost anywhere under the right conditions. Tornadoes also develop occasionally in southern Canada during the Northern Hemisphere's summer and somewhat regularly at other times of the year across Europe, Asia, Argentina, Australia and New Zealand. Tornadic events are often accompanied by other forms of severe weather, including strong thunderstorms, strong winds, and hail.
This page documents notable tornadoes and tornado outbreaks worldwide in 2022. Strong and destructive tornadoes form most frequently in the United States, Argentina, Brazil, Bangladesh, and Eastern India, but can occur almost anywhere under the right conditions. Tornadoes also develop occasionally in southern Canada during the Northern Hemisphere's summer and somewhat regularly at other times of the year across Europe, Asia, Argentina, Australia and New Zealand. Tornadic events are often accompanied by other forms of severe weather, including strong thunderstorms, strong winds, and hail.
Between March 29–31, 2022, a line of strong to severe thunderstorms and multiple supercells swept through portions of the United States and brought widespread wind damage and several strong tornadoes across a large part of the Midwestern, Southern, and Eastern United States. An EF3 tornado was confirmed in Springdale, Arkansas, while an EF1 tornado passed close to downtown Jackson, Mississippi. Numerous tornadoes, some of which were strong occurred over Mississippi, Alabama the evening of March 30 and into the early morning of March 31. Multiple tornadoes also occurred in the Florida Panhandle, including an intense EF3 tornado that killed two people and injured three others near Alford, Florida, and in other states such as North Carolina and Pennsylvania. One fatality occurred in Pope, Mississippi as a result of an EF1 tornado as well.
From April 4–5, 2022, a mesoscale convective system and numerous discrete supercells produced a swath of severe weather and several tornadoes in the Southeastern United States, including several strong, long tracked tornadoes. An EF3 tornado damaged or destroyed several homes in Bonaire, Georgia while a large EF3 tornado prompted a tornado emergency for Allendale and Sycamore, South Carolina. A violent EF4 tornado in Black Creek, Georgia resulted in one fatality as it destroyed several neighborhoods and another large EF3 tornado caused widespread heavy tree damage northeast of Ulmer, South Carolina. More severe storms occurred across a large portion of the Southeast ahead of a cold front on April 6–7, with more tornadoes reported in South and Central Georgia and further south into Florida, all of which were weak. Along with the one tornadic death, falling trees killed one person each in Louisiana and Texas.
The April 2022 North American storm complex affected much of the Rocky Mountains and the Midwestern United States with tornadoes, heavy snow, and gusty winds. The system in general first began impacting the Northwest on April 11, before moving eastward into the Rocky Mountains the following day. It was also responsible for producing a large severe weather outbreak of tornadoes and damaging straight-line wind in the Midwest and South while contributing to a powerful blizzard in the upper Midwest states of North and South Dakota.
On May 12, 2022, a severe squall line followed by a derecho took place across the Midwestern United States. Two fatalities occurred from the first line of storms while three more deaths occurred from the derecho itself.