Tornado outbreak
The examples and perspective in this article deal primarily with the United States and Canada and do not represent a worldwide view of the subject. (October 2019) |
A tornado outbreak is the occurrence of multiple tornadoes spawned by the same synoptic scale weather system.[1] The number of tornadoes required to qualify as an outbreak typically are at least six to ten, with at least two rotational locations (if squall line) or at least two supercells producing multiple tornadoes.[2][3]
The tornadoes usually occur within the same day or continue into the early morning hours of the succeeding day, and within the same region. Most definitions allow for a break in tornado activity (time elapsed from the end of the last tornado to the beginning of the next tornado) of six hours. If tornado activity indeed resumes after such a lull, many definitions consider the event to be a new outbreak. A series of continuous or nearly continuous tornado outbreak days is a
Very large tornado outbreaks are known as
Tornado outbreak sequence
A tornado outbreak sequence, or tornado outbreak day sequence, sometimes referred to as an extended tornado outbreak, is a period of continuous or nearly continuous high tornado activity consisting of a series of tornado outbreaks over multiple days with no or very few days lacking tornado outbreaks.[4]
Major tornado outbreak sequences occurred in the
Tornado outbreak sequences tend to dominate the tornado statistics for a year and often cause a spike in tornado numbers for the entire year. Not all periods of active tornado occurrences are outbreak sequences, there must be no break in the activity to satisfy the definition. Active periods occur ranging from every year to every several years whereas continuously active periods are less common and can be rare depending on the parameters applied to define a sequence. By the late 2010s, medium to long range forecasting advanced sufficiently that some periods of high tornado activity can be somewhat reliably predicted several days to several weeks in advance.[12]
See also
References
- ISBN 978-1-878220-34-9. Archived from the originalon 6 June 2011.
- ISBN 978-1-879362-03-1.
- .
- ^ a b Schneider, Russell; H.E. Brooks; J.T. Schaefer (October 2004). "Tornado Outbreak Day Sequences: historic events and climatology (1875-2003)". 22nd Conf. Severe Local Storms. Hyannis, MA: American Meteorological Society.
- ^ Schneider, Russell; H. E. Brooks; J. T. Schaefer (2004). "Tornado Outbreak Days: an updated and expanded climatology (1875-2003)". 22nd Conference on Severe Local Storms. Hyannis, MA: American Meteorological Society.
- S2CID 129795283.
- ^ Doswell, Charles A. III (2007). "Small Sample Size and Data Quality Issues Illustrated Using Tornado Occurrence Data". Electron. J. Sev. Storms Meteorol. 2 (5): 1–16.
- .
- .
- ^ Grazulis, Tom; Doris Grazulis. "1896 Tornadoes". The Tornado Project. Archived from the original on 26 February 2014. Retrieved 8 May 2008.
- S2CID 56010947. Archived from the original(PDF) on 18 February 2019.
- ^ a b Scientists forecasted late May tornado outbreak nearly four weeks before it ripped through U.S.
Further reading
- Corfidi, Stephen (2013). "Noteworthy North American Tornado Outbreaks". NOAA-NWS-NCEP Storm Prediction Center (poster).
- doi:10.1175/WAF959.1.
- Edwards, Roger; R. L. Thompson; C. Crosbie; J. A. Hart; C. A. Doswell (2004). "Proposals for modernizing definitions of tornado and severe thunderstorm outbreaks". 22nd Conference on Severe Local Storms. Hyannis, MA: American Meteorological Society.
- Forbes, Gregory S. (2006). "Meteorological aspects of high-impact tornado outbreaks". Symposium on the Challenges of Severe Convective Storms. Atlanta, GA: American Meteorological Society.
- Mercer, Andrew E.; C.M. Shafer; C.A. Doswell III; L.M. Leslie; M.B. Richman (December 2009). "Objective Classification of Tornadic and Nontornadic Severe Weather Outbreaks". Mon. Wea. Rev. 137 (12): 4355–68. S2CID 15831045.
- Moller, Alan R. (1979). "The Climatology and Synoptic Meteorology of Southern Plains' Tornado Outbreaks". M.S. Thesis. Norman, OK: University of Oklahoma.
- Shafer, Chad; C. Doswell (2011). "Using kernel density estimation to identify, rank, and classify severe weather outbreak events". Electron. J. Sev. Storms Meteorol. 6 (2).
- Shafer, Chad; C. Doswell; L. Leslie; M. Richman (2010). "On the use of areal coverage of parameters favorable for severe weather to discriminate major outbreaks". Electron. J. Sev. Storms Meteorol. 5 (7).
- Shafer, Chad; C.A. Doswell (2010). "A Multivariate Index for Ranking and Classifying Severe Weather Outbreaks". Electron. J. Sev. Storms Meteorol. 5 (1).
- Thompson, Richard L.; M.D. Vescio (1998). "The Destruction Potential Index – a method for comparing tornado days (DPI)". 19th Conference on Severe Local Storms. Minneapolis, MN: American Meteorological Society.
- Verbout, Stephanie M.; H.E. Brooks; L.M. Leslie; D.M. Schultz (2006). "Evolution of the U.S. Tornado Database: 1954-2003". Weather Forecast. 21 (1): 86–93. doi:10.1175/WAF910.1.
- Trapp, Robert J. (2014). "On the Significance of Multiple Consecutive Days of Tornado Activity". Mon. Wea. Rev. 142 (4): 1452–9. .