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.[1] 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.[2] The parcel descends rapidly, warming due to compression, overshoots its equilibrium level, and reaches the surface, similar to a downburst.[3]

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.

Characteristics

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.[4] 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.[5]

Causes

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.[6] 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.

Microburst cross section

Forecasting

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.[7]

Documented cases

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) [8]
14 June 2022 Tracy, Minnesota 80 °F (27 °C) 93 °F (34 °C) 13°F [9]
21 May 2022 Beja, Portugal 73.2 °F (22.9 °C) 92.1 °F (33.4 °C) 18.9°F [10]
20 May 2022 Greenville, North Carolina 73 °F (23 °C) 86 °F (30 °C) 13°F [11]
22 June 2021 Littleton, Colorado 72 °F (22 °C) 88 °F (31 °C) 16°F [12][13]
13 June 2021 Friona, Texas 70 °F (21 °C) 88.1 °F (31.2 °C) 18°F [14][15][16]
4 June 2020 Edmond, Oklahoma 97 °F (36 °C) [17]
25 July 2019 Donna Nook, Lincolnshire, England 71.6 °F (22.0 °C) 89.6 °F (32.0 °C) 18°F [18]
16 July 2017 Chicago, Illinois 72 °F (22 °C) 79 °F (26 °C) 7°F [19][20][21]
16 July 2017 Chicago, Illinois 73 °F (23 °C) 81 °F (27 °C) 8°F
July 2016[a] Hobart, Oklahoma 80.6 °F (27.0 °C) 105.7 °F (40.9 °C) 25.2°F [22]
July 2014 Calgary, Alberta 79 °F (26 °C) 84 °F (29 °C) 5°F [23][24][25][26]
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 [27][28][29]
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 [30]
15 May 2013 Dane County, Wisconsin 10°F [31]
14 May 2013 South Dakota 58 °F (14 °C) 79 °F (26 °C) 21°F [32]
1 July 2012 Georgetown, South Carolina 79 °F (26 °C) 90 °F (32 °C) 11°F [33]
3 May 2012 Bussey, Iowa 74 °F (23 °C) 85 °F (29 °C) 11°F [34][35]
29 April 2012 Torcy, Seine-et-Marne, France 56.1 °F (13.4 °C) 75 °F (24 °C) 18.9°F [36]
23 August 2011 Atlantic, Iowa 88 °F (31 °C) 102 °F (39 °C) 14°F [37][38][39]
3 July 2011 Indianapolis, Indiana 15°F [40]
9 June 2011 Wichita, Kansas 85 °F (29 °C) 102 °F (39 °C) 17°F [41]
29 October 2009 Buenos Aires, Argentina 87.8 °F (31.0 °C) 94.2 °F (34.6 °C) 6.4°F [42]
26 April 2009 Delmarva Peninsula 68 °F (20 °C) 87 °F (31 °C) 19°F [43]
18 August 2008 Edmonton, Alberta 72 °F (22 °C) 88 °F (31 °C) 16°F [44][45][46][47][48]
3 August 2008 Sioux Falls, South Dakota 70 °F (21 °C) 101 °F (38 °C) 31°F [49]
26 June 2008 Cozad, Nebraska 20°F [50][51]
16 June 2008 Midland, Texas 71 °F (22 °C) 97 °F (36 °C) 26°F [52][53]
25 May 2008 Emporia, Kansas 71 °F (22 °C) 91 °F (33 °C) 20°F [54]
16 July 2006 Canby, Minnesota 100 °F (38 °C) [55]
20 June 2006 Hastings, Nebraska 75 °F (24 °C) 94 °F (34 °C) 19°F [56][57]
12 June 2004 Wichita Falls, Texas 83 °F (28 °C) 94 °F (34 °C) 11°F [58][59]
May 1996 Chickasha, Oklahoma 87.6 °F (30.9 °C) 101.9 °F (38.8 °C) 14.3°F [60]
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 [61]
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. [62]

See also

Notes

  1. ^ This event lasted from 11:00 PM CDT, 6 July, to 12:15 AM CDT, 7 July

References

  1. ^ American Meteorological Society. (2000). Glossary of Meteorology. American Meteorological Society. ISBN 1-878220-34-9. Archived from the original on 6 June 2011.
  2. ^ "Oklahoma "heat burst" sends temperatures soaring". USA Today. 8 July 1999. Retrieved 9 May 2007.
  3. ^ Johnson, Jeffrey (December 2003). "Examination of a Long-Lived Heat Burst Event in the Northern Plains". National Weather Digest. National Weather Association. 27: 27–34. Archived from the original on 11 June 2005.
  4. ^ National Weather Service Albuquerque, NM Weather Forecast Office. "Heat Bursts". Retrieved from http://www.srh.noaa.gov/abq/?n=localfeatureheatburst
  5. ^ "All About Heat Bursts". National Weather Service. Retrieved 30 January 2015.
  6. ^ National Weather Service. Wilmington, North Carolina. "Georgetown Heat Burst." Retrieved from www.weather.gov/ilm/GeorgetownHeatBurst.
  7. ^ Kenneth Crawford, Justin Lane, Renee McPherson, William McPherson Jr. "A Climatological Analysis of Heat Bursts in Oklahoma (1994-2009)." International Journal of Climatology. Volume 31. Issue 4. Pages 531-544. (10 Mar.).
  8. ^ US Department of Commerce, NOAA. "Time Series Viewer". www.weather.gov. Retrieved 23 August 2022.
  9. ^ "NWS Twin Cities on Twitter". Twitter. Archived from the original on 14 June 2022. Retrieved 29 July 2022.
  10. ^ "IPMA - Detalhe noticia". www.ipma.pt. Retrieved 30 May 2022.
  11. ^ "NWS Newport/Morehead On Twitter". Twitter. Archived from the original on 23 June 2021. Retrieved 29 July 2022.
  12. ^ "NWS Boulder On Twitter". Twitter. Archived from the original on 23 June 2021. Retrieved 29 July 2022.
  13. ^ "Heat burst raises temperature 16 degrees in 30 minutes near Chatfield Reservoir". KDVR. June 2021. Archived from the original on 6 October 2021. Retrieved 29 July 2022.
  14. ^ "Mesonet Observation". West Texas Mesonet. 13 June 2021. Retrieved 13 June 2021.
  15. ^ IEMBot LUB [@iembot_lub] (13 June 2021). "At 1:55 AM CDT, 2 NE Friona [Parmer Co, TX] MESONET reports NON-TSTM WND GST of M68 MPH. HEAT BURST WITH SURFACE TEMPERATURE WARMING 18 DEGREES TO 88 DEGREES ACCOMPANIED BY A 68 MPH WIND GUST. TEMPERATURE WARMED TO 90 AT 30 FOOT AS WELL. NO LIGHTNING" (Tweet) – via Twitter.
  16. ^ NWS Lubbock [@NWSLubbock] (13 June 2021). "A heat burst just occurred at the West Texas Mesonet site in Friona. There was a wind gust of 68mph at 1:55am along with the temperature jumping from 70F to 87F. #lubwx #txwx" (Tweet) – via Twitter.
  17. ^ Cody Willis [@CodWWillisWX] (4 June 2020). "@spann Heat burst right now Edmond Oklahoma, it's 97 degrees at 10:17!" (Tweet) – via Twitter.
  18. ^ "'Heat burst': If you slept badly last night, this could be why". Sky News. 26 July 2019. Retrieved 26 July 2019.
  19. ^ "July 16, 2017: Sharp Overnight Temperature Climb Observed; Heat Burst?". NWS Chicago. 16 July 2017. Retrieved 13 June 2021.
  20. ^ "MESOWEST STATION INTERFACE". mesowest.utah.edu. Retrieved 13 June 2021.
  21. ^ "MESOWEST STATION INTERFACE". mesowest.utah.edu. Retrieved 13 June 2021.
  22. ^ "MESOWEST STATION INTERFACE". mesowest.utah.edu. Retrieved 15 September 2017.
  23. ^ "After Calgary's heat burst, what's in store for Wednesday?", The Weather Network, 31 July 2014, retrieved 2 August 2014
  24. ^ "Warm west - cool east", Valley Weather, Montreal, Quebec, 31 July 2014, retrieved 1 August 2014
  25. ^ "Hourly Data Report for July 29, 2014", Environment Canada Weather Office, 29 July 2014, archived from the original on 12 August 2014, retrieved 6 August 2014
  26. ^ "Calgary hit with not one, but two rare heat bursts, says Environment Canada", The Calgary Sun, 3 August 2014, archived from the original on 8 August 2014, retrieved 6 August 2014
  27. ^ "Latest Weather Observations for Laverton". Bureau of Meteorology. Archived from the original on 15 January 2014. Retrieved 15 January 2014.
  28. ^ "Latest Weather Observations for Cerberus". Bureau of Meteorology. Archived from the original on 15 January 2014. Retrieved 15 January 2014.
  29. ^ "Latest Weather Observations for Melbourne". Bureau of Meteorology. Archived from the original on 15 January 2014. Retrieved 15 January 2014.
  30. ^ "Riverside/Barr Weather". Wunderground.com. Retrieved 15 September 2017.
  31. ^ "'Heat burst' winds leave trail of downed lines". jsonline.com. Retrieved 15 September 2017.
  32. ^ "Gusty Winds This Morning From Apparent Heat Bursts". crh.noaa.gov. Retrieved 15 September 2017.
  33. ^ "Georgetown Heat Burst". www.weather.gov. Retrieved 25 March 2019.
  34. ^ "Rare phenomenon leads to bizarre weather event in Central Iowa". Des Moines Register.[permanent dead link]
  35. ^ "Rare heat burst just occurred in Iowa". KCCI. Archived from the original on 4 May 2012.
  36. ^ "24 °C en Île-de-France la nuit dernière, des rafales à 110 km/h !". METEO CONSULT - La Chaine Météo / Groupe Figaro.
  37. ^ "Heat Burst Affects Southwest Iowa". National Weather Service Des Moines, Iowa.
  38. ^ "Rare "Heat burst" hits Atlantic area". Radio Iowa. 24 August 2011.
  39. ^ "Temps Rocket From 80s to 102 in Minutes". KCCI. Archived from the original on 22 March 2012.
  40. ^ "Heat Burst Occurs in the Indianapolis Area".
  41. ^ http://www.kwch.com/kwch-jab-did-you-feel-this-mornings-heat-burst-20110609,0,5006130.story[permanent dead link]
  42. ^ "Heat Burst in Buenos Aires". meteored.com. Archived from the original on 12 July 2012. Retrieved 15 September 2017.
  43. ^ http://www.erh.noaa.gov/akq/wx_events/severe/HeatBurst42609/heatburst_20090426.htm[bare URL]
  44. ^ "The heat burst of 18 August 2008". University of Manitoba. University of Manitoba. Retrieved 19 March 2016.
  45. ^ "Hourly Data Report for August 18, 2008". Environment Canada. Environment Canada. Archived from the original on 29 March 2016. Retrieved 19 March 2016.
  46. ^ "Observations". University of Manitoba. University of Manitoba. Retrieved 19 March 2016.
  47. ^ "The evening tephigram from the region". University of Manitoba. University of Manitoba. Retrieved 19 March 2016.
  48. ^ "Reflectivity animation (RADAR)". University of Manitoba. University of Manitoba. Retrieved 19 March 2016.
  49. ^ "Convective Heat Burst moves across Sioux Falls". crh.noaa.gov. Retrieved 15 September 2017.
  50. ^ "Cozad, Nebraska - News - Evri". Archived from the original on 23 July 2011. Retrieved 12 November 2010.
  51. ^ "NTV - KHGI/KWNB/WSWS-CA - Where your news comes first. - Grand Island, Kearney, Hastings, Lincoln | Cozad Witnesses Rare Weather". Archived from the original on 30 June 2008.
  52. ^ http://www.mywesttexas.com/articles/2008/06/17/news/top_stories/doc4857af7c54b33314052160.txt[permanent dead link]
  53. ^ "Midland Heat Burst - Damage Survey". noaa.gov. Retrieved 15 September 2017.
  54. ^ "Special Weather Statement". National Weather Service, Topeka, Kansas. Retrieved 25 May 2008.
  55. ^ "Late Night Heat Burst in Western Minnesota on 16–17 July 2006". National Weather Service, Twin Cities. Archived from the original on 1 September 2006. Retrieved 9 May 2007.
  56. ^ "Weather History for Hastings, NE". wunderground.com. Retrieved 15 September 2017.
  57. ^ "Hastings, NE". crh.noaa.gov. Retrieved 15 September 2017.
  58. ^ "Daily Historical Weather Browser". Archived from the original on 19 October 2012. Retrieved 9 June 2011.
  59. ^ "Heat Burst strikes OK/KS late Friday night". storm2k.org. Retrieved 15 September 2017.
  60. ^ Cappella, Chris (23 June 1999). "Heat burst captured by weather network". USA Today. Retrieved 9 May 2007.
  61. ^ ARÚS DUMENJO, J. (2001): "Reventones de tipo cálido en Cataluña", V Simposio nacional de predicción del Instituto Nacional de Meteorología, Ministerio de Medio Ambiente, Madrid, págs. 1-7 Repositorio Arcimís, http://repositorio.aemet.es/handle/20.500.11765/4699 (versión electrónica).[1] [2] [3] [4]
  62. ^ "The Kopperl Heat Burst". 15 June 2009.