Rapid intensification

File:Hurricane Patricia RAMMB loop.gif's {{cvt|54|m/s|km/h mph|adj=on}} 24-hour wind speed increase was the largest of any tropical cyclone on record.|alt=Animated infrared satellite imagery of a tropical cyclone]]

There is no globally consistent definition of rapid intensification. Thresholds for rapid intensification{{snd}}by the magnitude of increase in maximum sustained winds and the brevity of the intensification period{{snd}}are based on the distribution of high-percentile intensification cases in the respective tropical cyclone basins. The thresholds also depend on the averaging period used to assess the storm's winds.{{cite journal |last1=Tam |first1=Hiu-fai |last2=Choy |first2=Chun-wing |last3=Wong |first3=Wai-kin |title=Development of objective forecast guidance on tropical cyclone rapid intensity change |journal=Meteorological Applications |date=March 2021 |volume=28 |issue=2 |page=1981 |doi=10.1002/met.1981|doi-access=free |bibcode=2021MeApp..28.1981T }}{{efn|The recorded sustained speed of the wind depends on the length of time over which near-instantaneous wind speeds are averaged. In contrast to wind gust measurements, sustained wind measurements are treated as representative of the background mean wind. The World Meteorological Organization standard for gauging the mean wind is a 10-minute average, but 1-minute and 3-minute averaging periods are also commonly used to estimate tropical cyclone wind speeds.{{cite report|type=Technical Document|last1=Harper |first1=B. A. |last2=Kepert |first2=J. D. |last3=Ginger |first3=J. D. |title=Guidelines for converting between various wind averaging periods in tropical cyclone conditions (WMO/TD-No. 1555)|date=August 2010 |url=https://library.wmo.int/viewer/48652?medianame=wmo-td_1555_en_ |access-date=6 November 2023 |publisher=World Meteorological Organization |location=Geneva, Switzerland}}|name=sustained}} In 2003, John Kaplan of the Hurricane Research Division and Mark DeMaria of the Regional and Mesoscale Meteorology Team at Colorado State University defined rapid intensification as an increase in the maximum one-minute sustained winds of a tropical cyclone of at least {{convert|30|knot|km/h mph|round=5}} in a 24-hour period. This increase in winds approximately corresponds to the 95th percentile of Atlantic tropical cyclone intensity changes over water from 1989 to 2000.{{cite journal |last1=Kaplan |first1=John |last2=DeMaria |first2=Mark |title=Large-Scale Characteristics of Rapidly Intensifying Tropical Cyclones in the North Atlantic Basin |journal=Weather and Forecasting |date=December 2003 |volume=18 |issue=6 |pages=1093–1108 |doi=10.1175/1520-0434(2003)018<1093:LCORIT>2.0.CO;2|doi-access=free |bibcode=2003WtFor..18.1093K }}{{cite journal |last1=Bhatia |first1=Kieran |last2=Baker |first2=Alexander |last3=Yang |first3=Wenchang |last4=Vecchi |first4=Gabriel |last5=Knutson |first5=Thomas |last6=Murakami |first6=Hiroyuki |last7=Kossin |first7=James |last8=Hodges |first8=Kevin |last9=Dixon |first9=Keith |last10=Bronselaer |first10=Benjamin |last11=Whitlock |first11=Carolyn |title=A potential explanation for the global increase in tropical cyclone rapid intensification |journal=Nature Communications |date=November 2022 |volume=13 |issue=1 |page=6626 |doi=10.1038/s41467-022-34321-6|doi-access=free |pmid=36333371 |pmc=9636401 |bibcode=2022NatCo..13.6626B }} These thresholds for defining rapid intensification are commonly used, but other thresholds are utilized in related scientific literature.{{cite journal |last1=Li |first1=Yi |last2=Tang |first2=Youmin |last3=Toumi |first3=Ralf |last4=Wang |first4=Shuai |title=Revisiting the Definition of Rapid Intensification of Tropical Cyclones by Clustering the Initial Intensity and Inner-Core Size |journal=Journal of Geophysical Research: Atmospheres |date=October 2022 |volume=127 |issue=20 |doi=10.1029/2022JD036870|arxiv=2208.13140 |bibcode=2022JGRD..12736870L }} The U.S. National Hurricane Center (NHC) reflects the thresholds of Kaplan and DeMaria in its definition of rapid intensification.{{cite web |title=Glossary of NHC Terms |url=https://www.nhc.noaa.gov/aboutgloss.shtml |publisher=National Hurricane Center |access-date=3 November 2023 |location=Miami, Florida}} The NHC also defines a similar quantity, rapid deepening, as a decrease in the minimum barometric pressure in a tropical cyclone of at least {{cvt|42|mbar|inHg|lk=on}} in 24 hours.{{cite journal |last1=Prikryl |first1=Paul |last2=Nikitina |first2=Lidia |last3=Rušin |first3=Vojto |title=Rapid intensification of tropical cyclones in the context of the solar wind-magnetosphere-ionosphere-atmosphere coupling |journal=Journal of Atmospheric and Solar-Terrestrial Physics |date=February 2019 |volume=183 |pages=36–60 |doi=10.1016/j.jastp.2018.12.009|doi-access=free |bibcode=2019JASTP.183...36P }}

Around 20–30% of all tropical cyclones experience at least one period of rapid intensification, including a majority of tropical cyclones with winds exceeding {{cvt|51|m/s|km/h mph}}.{{cite book |last1=Sippel |first1=J.A. |editor1-last=North |editor1-first=Gerald R. |editor2-last=Pyle |editor2-first=John |editor3-last=Zhang |editor3-first=Fuqing |title=Encyclopedia of Atmospheric Sciences |date=2015 |publisher=Elsevier |isbn=978-0-12-382225-3 |pages=32–33 |edition=Second |url=|doi=10.1016/B978-0-12-382225-3.00497-7 |chapter=Hurricane Predictability}} The tendency for strong tropical cyclones to have undergone rapid intensification and the infrequency with which storms gradually strengthen to strong intensities leads to a bimodal distribution in global tropical cyclone intensities, with weaker and stronger tropical cyclones being more commonplace than tropical cyclones of intermediate strength.{{cite journal |last1=Lee |first1=Chia-Ying |last2=Tippett |first2=Michael K. |last3=Sobel |first3=Adam H. |last4=Camargo |first4=Suzana J. |title=Rapid intensification and the bimodal distribution of tropical cyclone intensity |journal=Nature Communications |date=3 February 2016 |volume=7 |issue=1 |page=10625 |doi=10.1038/ncomms10625|doi-access=free |pmid=26838056 |pmc=4742962 |bibcode=2016NatCo...710625L }} Episodes of rapid intensification typically last longer than 24 hours. Within the North Atlantic, intensification rates are on average fastest for storms with maximum one-minute sustained wind speeds of {{cvt|70|–|80|knot|km/h mph|round=5}}. In the South-West Indian Ocean, intensification rates are fastest for storms with maximum ten-minute sustained wind speeds of {{cvt|65|–|75|knot|km/h mph|round=5}}. Smaller tropical cyclones are more likely to undergo quick intensity changes, including rapid intensification, potentially due to a greater sensitivity to their surrounding environments. Hurricane Patricia experienced a {{cvt|54|m/s|km/h mph}} increase in its maximum sustained winds over 24 hours in 2015, setting a global record for 24-hour wind speed increase.{{cite journal |last1=Rogers |first1=Robert F. |last2=Aberson |first2=Sim |last3=Bell |first3=Michael M. |last4=Cecil |first4=Daniel J. |last5=Doyle |first5=James D. |last6=Kimberlain |first6=Todd B. |last7=Morgerman |first7=Josh |last8=Shay |first8=Lynn K. |last9=Velden |first9=Christopher |title=Rewriting the Tropical Record Books: The Extraordinary Intensification of Hurricane Patricia (2015) |journal=Bulletin of the American Meteorological Society |date=October 2017 |volume=98 |issue=10 |pages=2091–2112 |doi=10.1175/BAMS-D-16-0039.1|bibcode=2017BAMS...98.2091R }} Patricia also holds the record for the largest pressure decrease in 24 hours based on RSMC data, deepening {{cvt|97|mbar|inHg}}. However, other estimates suggest Typhoon Forrest's central pressure may have deepened by as much as {{cvt|104|mbar|inHg}} in 1983, and the World Meteorological Organization lists Forrest's intensification rate as the fastest on record.{{cite web |title=Tropical Cyclone: Fastest Intensification of Tropical Cyclone |url=https://wmo.asu.edu/content/tropical-cyclone-fastest-intensification-tropical-cyclone |website=World Meteorological Organization's World Weather & Climate Extremes Archive |publisher=Arizona State University |access-date=11 November 2023}} In 2019, the Joint Typhoon Warning Center (JTWC) estimated that Cyclone Ambali's winds increased by {{cvt|51|m/s|km/h mph}} in 24 hours, marking the highest 24-hour wind speed increase for a tropical cyclone in the Southern Hemisphere since at least 1980.{{cite web |last1=Masters |first1=Jeff |title=A Rogues' Gallery of the Five Category 5 Storms of 2019 |url=https://blogs.scientificamerican.com/eye-of-the-storm/a-rogues-gallery-of-the-five-category-5-storms-of-2019/ |website=Eye of the Storm |publisher=Scientific American |access-date=6 November 2023 |date=9 January 2020}}{{cite news |last1=Cappucci |first1=Matthew |last2=Freedman |first2=Andrew |title=Record-setting Tropical Cyclone Ambali intensifies from tropical storm to borderline Category 5 monster in 24 hours |url=https://www.washingtonpost.com/weather/2019/12/06/record-setting-tropical-cyclone-ambali-intensifies-tropical-storm-category-monster-hours/ |url-access=subscription |access-date=6 November 2023 |newspaper=The Washington Post |date=6 December 2019}}

File:Delta 2020 rapid intensification.gif

Tropical cyclones frequently become more axisymmetric prior to rapid intensification, with a strong relationship between a storm's degree of axisymmetry during initial development and its intensification rate. However, the asymmetric emergence of strong convection and hot towers near within inner core of tropical cyclones can also portend rapid intensification. The development of localized deep convection (termed "convective bursts") increases the structural organization of tropical cyclones in the upper troposphere and offsets the entrainment of drier and more stable air from the lower stratosphere, but whether bursts of deep convection induce rapid intensification or vice versa is unclear.{{cite journal |last1=Hendricks |first1=Eric A. |last2=Braun |first2=Scott A. |last3=Vigh |first3=Jonathan L. |last4=Courtney |first4=Joseph B. |title=A summary of research advances on tropical cyclone intensity change from 2014-2018 |journal=Tropical Cyclone Research and Review |date=December 2019 |volume=8 |issue=4 |pages=219–225 |doi=10.1016/j.tcrr.2020.01.002|doi-access=free |bibcode=2019TCRR....8..219H }} Hot towers have been implicated in rapid intensification, though they have diagnostically seen varied impacts across basins.{{cite journal |last1=Zhuge |first1=Xiao-Yong |last2=Ming |first2=Jie |last3=Wang |first3=Yuan |title=Reassessing the Use of Inner-Core Hot Towers to Predict Tropical Cyclone Rapid Intensification* |journal=Weather and Forecasting |date=October 2015 |volume=30 |issue=5 |pages=1265–1279 |doi=10.1175/WAF-D-15-0024.1|doi-access=free |bibcode=2015WtFor..30.1265Z }} The frequency and intensity of lightning in the inner core region may be related to rapid intensification.{{cite journal |last1=Vagasky |first1=Chris |title=Enveloped Eyewall Lightning: The EEL Signature in Tropical Cyclones |journal=Journal of Operational Meteorology |date=November 2017 |volume=5 |issue=14 |pages=171–179 |doi=10.15191/nwajom.2017.0514|doi-access=free }}{{cite journal |last1=Slocum |first1=Christopher J. |last2=Knaff |first2=John A. |last3=Stevenson |first3=Stephanie N. |title=Lightning-Based Tropical Cyclone Rapid Intensification Guidance |journal=Weather and Forecasting |date=July 2023 |volume=38 |issue=7 |pages=1209–1227 |doi=10.1175/WAF-D-22-0157.1|bibcode=2023WtFor..38.1209S |url=https://repository.library.noaa.gov/view/noaa/54707 }}{{cite journal |last1=Duran |first1=Patrick |last2=Schultz |first2=Christopher J. |last3=Bruning |first3=Eric C. |last4=Stevenson |first4=Stephanie N. |last5=PeQueen |first5=David J. |last6=Johnson |first6=Nicholas E. |last7=Allen |first7=Roger E. |last8=Smith |first8=Matthew R. |last9=LaFontaine |first9=Frank J. |title=The Evolution of Lightning Flash Density, Flash Size, and Flash Energy During Hurricane Dorian's (2019) Intensification and Weakening |journal=Geophysical Research Letters |date=April 2021 |volume=48 |issue=8 |doi=10.1029/2020GL092067|bibcode=2021GeoRL..4892067D |url=https://repository.library.noaa.gov/view/noaa/46397 }} A survey of tropical cyclones sampled by the Tropical Rainfall Measuring Mission suggested that rapidly intensifying storms were distinguished from other storms by the large extent and high magnitude of rainfall in their inner core regions.{{cite journal |last1=Jiang |first1=Haiyan |last2=Ramirez |first2=Ellen M. |title=Necessary Conditions for Tropical Cyclone Rapid Intensification as Derived from 11 Years of TRMM Data |journal=Journal of Climate |date=September 2013 |volume=26 |issue=17 |pages=6459–6470 |doi=10.1175/JCLI-D-12-00432.1|doi-access=free |bibcode=2013JCli...26.6459J }} However, the physical mechanisms that drive rapid intensification do not appear to be fundamentally different from those that drive slower rates of intensification.{{cite journal |last1=Kowch |first1=Roman |last2=Emanuel |first2=Kerry |title=Are Special Processes at Work in the Rapid Intensification of Tropical Cyclones? |journal=Monthly Weather Review |date=March 2015 |volume=143 |issue=3 |pages=878–882 |doi=10.1175/MWR-D-14-00360.1|doi-access=free |bibcode=2015MWRv..143..878K |hdl=1721.1/98391 |hdl-access=free }}

File:MMI of Jelawat rapidly intensifying.gif imagery of Typhoon Jelawat during a period of rapid intensification in March 2018{{cite journal |last1=Zou |first1=Xiaolei |last2=Tian |first2=Xiaoxu |title=Comparison of ATMS Striping Noise Between NOAA-20 and S-NPP and Noise Impact on Warm Core Retrieval of Typhoon Jelawat (2018) |journal=IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing |date=July 2019 |volume=12 |issue=7 |pages=2504–2512 |doi=10.1109/JSTARS.2019.2891683|bibcode=2019IJSTA..12.2504Z }}|alt=Animated view of a rapidly intensifying typhoon]]

The characteristics of environments in which storms rapidly intensify do not vastly differ from those that engender slower intensification rates. High sea surface temperatures and oceanic heat content are potentially crucial in enabling rapid intensification.{{cite journal |last1=Elsberry |first1=Russell L. |last2=Chen |first2=Lianshou |last3=Davidson |first3=Jim |last4=Rogers |first4=Robert |last5=Wang |first5=Yuqing |last6=Wu |first6=Liguang |title=Advances in Understanding and Forecasting Rapidly Changing Phenomena in Tropical Cyclones |journal=Tropical Cyclone Research and Review |date=February 2013 |volume=2 |issue=1 |pages=13–24 |doi=10.6057/2013TCRR01.02|bibcode=2013TCRR....2...13E }} Waters with strong horizontal SST gradients or strong salinity stratification may favor stronger air–sea fluxes of enthalpy and moisture, providing more conducive conditions for rapid intensification.{{cite journal |last1=Wadler |first1=Joshua B. |last2=Rudzin |first2=Johna E. |last3=Jaimes de la Cruz |first3=Benjamin |last4=Chen |first4=Jie |last5=Fischer |first5=Michael |last6=Chen |first6=Guanghua |last7=Qin |first7=Nannan |last8=Tang |first8=Brian |last9=Li |first9=Qingqing |title=A review of Recent Research Progress on the Effect of External Influences on Tropical Cyclone Intensity Change |journal=Tropical Cyclone Research and Review |date=September 2023 |volume=12 |issue=3 |pages=200–215 |doi=10.1016/j.tcrr.2023.09.001|doi-access=free |bibcode=2023TCRR...12..200W }} The presence of a favorable environment alone does not always lead to rapid intensification.{{cite web |last1=Voiland |first1=Adam |title=A Closer Look at Rapidly Intensifying Hurricanes |url=https://earthobservatory.nasa.gov/images/91130/a-closer-look-at-rapidly-intensifying-hurricanes |website=NASA Earth Observatory |publisher=NASA |access-date=11 November 2023 |date=17 October 2017}} Vertical wind shear adds additional uncertainty in predicting the behavior of storm intensity and the timing of rapid intensification. The presence of wind shear concentrates convective available potential energy (CAPE) and helicity and strengthens inflow within the downshear{{efn|The downshear side of a tropical cyclone is the side in the direction of the wind shear vector, analogous to downwind. The upshear side of a tropical cyclone is the side opposite the direction of the wind shear vector, analogous to upwind.|name=downshear}} region of the tropical cyclone. Such conditions are conducive to vigorous rotating convection, which can induce rapid intensification if located close enough to the tropical cyclone's core of high vorticity. However, wind shear also concurrently produces conditions unfavorable to convection within a tropical cyclone's upshear{{efn|name=downshear}} region by entraining dry air into the storm and inducing subsidence. These upshear conditions can be brought into the initially favorable downshear regions, becoming deleterious to the tropical cyclone's intensity and forestalling rapid intensification. Simulations also suggest that rapid intensification episodes are sensitive to the timing of wind shear. Tropical cyclones that undergo rapid intensification in the presence of moderate ({{cvt|5|–|10|m/s|km/h mph|round=5}}) wind shear may exhibit similarly asymmetric convective structures.{{cite journal |last1=Ryglicki |first1=David R. |last2=Cossuth |first2=Joshua H. |last3=Hodyss |first3=Daniel |last4=Doyle |first4=James D. |title=The Unexpected Rapid Intensification of Tropical Cyclones in Moderate Vertical Wind Shear. Part I: Overview and Observations |journal=Monthly Weather Review |date=November 2018 |volume=146 |issue=11 |pages=3773–3800 |doi=10.1175/MWR-D-18-0020.1|doi-access=free |bibcode=2018MWRv..146.3773R }} In such cases, outflow from the sheared tropical cyclone may interact with the surrounding environment in ways that locally reduce wind shear and permit further intensification.{{cite journal |last1=Ryglicki |first1=David R. |last2=Doyle |first2=James D. |last3=Hodyss |first3=Daniel |last4=Cossuth |first4=Joshua H. |last5=Jin |first5=Yi |last6=Viner |first6=Kevin C. |last7=Schmidt |first7=Jerome M. |title=The Unexpected Rapid Intensification of Tropical Cyclones in Moderate Vertical Wind Shear. Part III: Outflow–Environment Interaction |journal=Monthly Weather Review |date=August 2019 |volume=147 |issue=8 |pages=2919–2940 |doi=10.1175/MWR-D-18-0370.1|doi-access=free |bibcode=2019MWRv..147.2919R }} The interaction of tropical cyclones with upper-tropospheric troughs can also be conducive to rapid intensification, particularly when involving troughs with shorter wavelengths and larger distances between the trough and the tropical cyclone.

Within environments favorable for rapid intensification, stochastic internal processes within storms play a larger role in modulating the rate of intensification. In some cases, the onset of rapid intensification is preceded by the large release of convective instability from moist air (characterized by high equivalent potential temperature), enabling an increase in convection around the center of the tropical cyclone. Rapid intensification events may also be related to the character and distribution of convection about the tropical cyclone. One study indicated that a substantial increase in stratiform precipitation throughout the storm signified the beginning of rapid intensification. In 2023, a National Center for Atmospheric Research study of rapid intensification using computer simulations identified two pathways for tropical cyclones to rapidly intensifying. In the "marathon" mode of rapid intensification, conducive environmental conditions including low wind shear and high SSTs promote symmetric intensification of tropical cyclone at a relatively moderate pace over a prolonged period. The "sprint" mode of rapid intensification is faster and more brief, but typically occurs in conditions long assumed to be unfavorable for intensification, such as in the presence of strong wind shear. This faster mode involves convective bursts removed from the tropical cyclone center that can rearrange the storm circulation or produce a new center of circulation. The modeled tropical cyclones undergoing the sprint mode of rapid intensification tended to peak at lower intensities (sustained winds below {{cvt|51|m/s|km/h mph|round=5}}) than those undergoing the marathon mode of rapid intensification.{{cite journal |last1=Judt |first1=Falko |last2=Rios-Berrios |first2=Rosimar |last3=Bryan |first3=George H. |title=Marathon versus Sprint: Two Modes of Tropical Cyclone Rapid Intensification in a Global Convection-Permitting Simulation |journal=Monthly Weather Review |date=October 2023 |volume=151 |issue=10 |pages=2683–2699 |doi=10.1175/MWR-D-23-0038.1|bibcode=2023MWRv..151.2683J }}{{cite web |last1=Hosansky |first1=David |title=Scientists find two ways that hurricanes rapidly intensify |url=https://news.ucar.edu/132924/scientists-find-two-ways-hurricanes-rapidly-intensify |website=NCAR & UCAR News |publisher=University Corporation for Atmospheric Research |access-date=6 November 2023 |date=26 October 2023}}

File:Intensity error, OWID.svgs as a key area for improvement.|alt=Graph of trends in intensity errors]]

Rapid intensification is a significant source of error in tropical cyclone forecasting, and the timing of rapid intensification episodes has low predictability.{{cite journal |last1=Wang |first1=Y. |last2=Wu |first2=C.-C. |title=Current understanding of tropical cyclone structure and intensity changes ? a review |journal=Meteorology and Atmospheric Physics |date=December 2004 |volume=87 |issue=4 |pages=257–278 |doi=10.1007/s00703-003-0055-6|bibcode=2004MAP....87..257W }} Rapid intensity changes near land can greatly influence tropical cyclone preparedness and public risk perception. Increasing the predictability of rapid intensity changes has been identified as a top priority by operational forecasting centers. In 2012, the NHC listed prediction of rapid intensification as their highest priority item for improvement.{{cite journal |last1=Carrasco |first1=Cristina Alexandra |last2=Landsea |first2=Christopher William |last3=Lin |first3=Yuh-Lang |title=The Influence of Tropical Cyclone Size on Its Intensification |journal=Weather and Forecasting |date=June 2014 |volume=29 |issue=3 |pages=582–590 |doi=10.1175/WAF-D-13-00092.1|doi-access=free |bibcode=2014WtFor..29..582C }} Genesis and Rapid Intensification Processes (GRIP) was a field experiment led by NASA Earth Science to in part study rapid intensification. Multiple aircraft including the uncrewed Northrop Grumman RQ-4 Global Hawk were used to probe the rapid intensification events of hurricanes Earl and Karl during the 2010 Atlantic hurricane season.{{cite journal |last1=Braun |first1=Scott A. |last2=Kakar |first2=Ramesh |last3=Zipser |first3=Edward |last4=Heymsfield |first4=Gerald |last5=Albers |first5=Cerese |last6=Brown |first6=Shannon |last7=Durden |first7=Stephen L. |last8=Guimond |first8=Stephen |last9=Halverson |first9=Jeffery |last10=Heymsfield |first10=Andrew |last11=Ismail |first11=Syed |last12=Lambrigtsen |first12=Bjorn |last13=Miller |first13=Timothy |last14=Tanelli |first14=Simone |last15=Thomas |first15=Janel |last16=Zawislak |first16=Jon |title=NASA's Genesis and Rapid Intensification Processes (GRIP) Field Experiment |journal=Bulletin of the American Meteorological Society |date=March 2013 |volume=94 |issue=3 |pages=345–363 |doi=10.1175/BAMS-D-11-00232.1|doi-access=free |bibcode=2013BAMS...94..345B |hdl=11603/28542 |hdl-access=free }}{{cite web |title=Genesis and Rapid Intensification Processes (GRIP) |url=https://ghrc.nsstc.nasa.gov/home/field-campaigns/grip |website=GHRC |publisher=NASA |access-date=5 November 2023}} In December 2016, the CYGNSS SmallSat constellation was launched with a goal of measure ocean surface wind speeds with sufficiently high temporal resolution to resolve rapid intensification events.{{cite web |title=Cyclone Global Navigation Satellite System (CYGNSS) |url=http://cygnss.engin.umich.edu/wp-content/uploads/sites/534/2021/06/CYGNSS_FactSheet_171020.pdf |publisher=University of Michigan |access-date=6 November 2023 |location=Ann Arbor, Michigan }}{{cite web |last1=Ruf |first1=Chris |title=Five Years and Counting – Happy Birthday to the CYGNSS Octuplets! |url=https://earthobservatory.nasa.gov/blogs/fromthefield/2021/12/15/five-years-and-counting-happy-birthday-to-the-cygnss-octuplets/ |website=Notes from the Field |publisher=NASA Earth Observatory |access-date=6 November 2023 |date=15 December 2021}}{{cite journal |last1=Leroux |first1=Marie-Dominique |last2=Wood |first2=Kimberly |last3=Elsberry |first3=Russell L. |last4=Cayanan |first4=Esperanza O. |last5=Hendricks |first5=Eric |last6=Kucas |first6=Matthew |last7=Otto |first7=Peter |last8=Rogers |first8=Robert |last9=Sampson |first9=Buck |last10=Yu |first10=Zifeng |title=Recent Advances in Research and Forecasting of Tropical Cyclone Track, Intensity, and Structure at Landfall |journal=Tropical Cyclone Research and Review |date=May 2018 |volume=7 |issue=2 |pages=85–105 |doi=10.6057/2018TCRR02.02|bibcode=2018TCRR....7...85L }} The TROPICS satellite constellation includes studying rapid changes in tropical cyclones as one of its core science objectives.{{cite journal |last1=Blackwell |first1=W. J. |last2=Braun |first2=S. |last3=Bennartz |first3=R. |last4=Velden |first4=C. |last5=DeMaria |first5=M. |last6=Atlas |first6=R. |last7=Dunion |first7=J. |last8=Marks |first8=F. |last9=Rogers |first9=R. |last10=Annane |first10=B. |last11=Leslie |first11=R. V. |title=An overview of the TROPICS NASA Earth Venture Mission |journal=Quarterly Journal of the Royal Meteorological Society |date=November 2018 |volume=144 |issue=S1 |pages=16–26 |doi=10.1002/qj.3290 |pmid=30774158 |pmc=6360932|bibcode=2018QJRMS.144...16B }} Weather models have also shown an improved ability to project rapid intensification events,{{cite journal |last1=Cangialosi |first1=John P. |last2=Blake |first2=Eric |last3=DeMaria |first3=Mark |last4=Penny |first4=Andrew |last5=Latto |first5=Andrew |last6=Rappaport |first6=Edward |last7=Tallapragada |first7=Vijay |title=Recent Progress in Tropical Cyclone Intensity Forecasting at the National Hurricane Center |journal=Weather and Forecasting |date=1 October 2020 |volume=35 |issue=5 |pages=1913–1922 |doi=10.1175/WAF-D-20-0059.1|doi-access=free |bibcode=2020WtFor..35.1913C }} but continue to face difficulties in accurately depicting their timing and magnitude.{{cite journal |last1=Zhang |first1=Zhan |last2=Wang |first2=Weiguo |last3=Doyle |first3=James D. |last4=Moskaitis |first4=Jonathan |last5=Komaromi |first5=William A. |last6=Heming |first6=Julian |last7=Magnusson |first7=Linus |last8=Cangialosi |first8=John P. |last9=Cowan |first9=Levi |last10=Brennan |first10=Michael |last11=Ma |first11=Suhong |last12=Das |first12=Ananda Kumar |last13=Takuya |first13=Hosomi |last14=Clegg |first14=Peter |last15=Birchard |first15=Thomas |last16=Knaff |first16=John A. |last17=Kaplan |first17=John |last18=Mohapatra |first18=Mrutyunjay |last19=Sharma |first19=Monica |last20=Masaaki |first20=Ikegami |last21=Wu |first21=Liguang |last22=Blake |first22=Eric |title=A review of recent advances (2018–2021) on tropical cyclone intensity change from operational perspectives, part 1: Dynamical model guidance |journal=Tropical Cyclone Research and Review |date=March 2023 |volume=12 |issue=1 |pages=30–49 |doi=10.1016/j.tcrr.2023.05.004|doi-access=free |bibcode=2023TCRR...12...30Z }} Statistical models show greater forecast skill in anticipating rapid intensification compared to dynamical weather models.{{cite journal |last1=Kaplan |first1=John |last2=Rozoff |first2=Christopher M. |last3=DeMaria |first3=Mark |last4=Sampson |first4=Charles R. |last5=Kossin |first5=James P. |last6=Velden |first6=Christopher S. |last7=Cione |first7=Joseph J. |last8=Dunion |first8=Jason P. |last9=Knaff |first9=John A. |last10=Zhang |first10=Jun A. |last11=Dostalek |first11=John F. |last12=Hawkins |first12=Jeffrey D. |last13=Lee |first13=Thomas F. |last14=Solbrig |first14=Jeremy E. |title=Evaluating Environmental Impacts on Tropical Cyclone Rapid Intensification Predictability Utilizing Statistical Models |journal=Weather and Forecasting |date=October 2015 |volume=30 |issue=5 |pages=1374–1396 |doi=10.1175/WAF-D-15-0032.1|doi-access=free |bibcode=2015WtFor..30.1374K }} Intensity predictions derived from artificial neural networks may also provide more accurate predictions of rapid intensification than established methods.

File:Marcus 2018-03-21 0600Z.jpg was an instance in which operational intensity forecasts successfully predicted rapid intensification with the aid of RI forecast aids.|alt=Satellite image of a tropical cyclone]]

Because forecast errors at 24-hour leadtimes are greater for rapidly intensifying tropical cyclones than other cases, operational forecasts do not typically depict rapid intensification.{{cite journal |last1=Courtney |first1=Joseph B. |last2=Langlade |first2=Sébastien |last3=Barlow |first3=Stephen |last4=Birchard |first4=Thomas |last5=Knaff |first5=John A. |last6=Kotal |first6=S.D. |last7=Kriat |first7=Tarik |last8=Lee |first8=Woojeong |last9=Pasch |first9=Richard |last10=Sampson |first10=Charles R. |last11=Shimada |first11=Udai |last12=Singh |first12=Amit |title=Operational perspectives on tropical cyclone intensity change Part 2: forecasts by operational agencies |journal=Tropical Cyclone Research and Review |date=December 2019 |volume=8 |issue=4 |pages=226–239 |doi=10.1016/j.tcrr.2020.01.003|doi-access=free |bibcode=2019TCRR....8..226C }} Probabilistic and deterministic forecasting tools have been developed to increase forecast confidence and aid forecasters in anticipating rapid intensification episodes. These aids have been integrated into the operational forecasting procedures of Regional Specialized Meteorological Centers (RSMCs) and are factored into tropical cyclone intensity forecasts worldwide. For example, the Rapid Intensification Index (RII){{snd}}a quantification of the likelihood of rapid intensification for varying degrees of wind increases based on forecasts of environmental parameters{{cite journal |last1=Kaplan |first1=John |last2=DeMaria |first2=Mark |last3=Knaff |first3=John A. |title=A Revised Tropical Cyclone Rapid Intensification Index for the Atlantic and Eastern North Pacific Basins |journal=Weather and Forecasting |date=February 2010 |volume=25 |issue=1 |pages=220–241 |doi=10.1175/2009WAF2222280.1|doi-access=free |bibcode=2010WtFor..25..220K }}{{snd}}is utilized by RSMC Tokyo–Typhoon Center, the Australian Bureau of Meteorology (BOM), and the NHC. An intensity prediction product is being developed at RSMC La Réunion for the South-West Indian Ocean based on tools developed in other tropical cyclone basins. The Rapid Intensity Prediction Aid (RIPA) increases the consensus intensity forecast provided by the JTWC's principal tropical cyclone intensity forecasting aid if at least a 40% chance of rapid intensification is assessed and has been used since 2018. The JTWC reported that a large increasing trend in the probability of rapid intensification assessed using RIPA was associated with higher likelihoods of rapid intensification. The JTWC is also experimenting with additional rapid intensification forecasting aids relying on a variety of statistical methods.{{cite journal |last1=Wang |first1=Weiguo |last2=Zhang |first2=Zhan |last3=Cangialosi |first3=John P. |last4=Brennan |first4=Michael |last5=Cowan |first5=Levi |last6=Clegg |first6=Peter |last7=Takuya |first7=Hosomi |last8=Masaaki |first8=Ikegami |last9=Das |first9=Ananda Kumar |last10=Mohapatra |first10=Mrutyunjay |last11=Sharma |first11=Monica |last12=Knaff |first12=John A. |last13=Kaplan |first13=John |last14=Birchard |first14=Thomas |last15=Doyle |first15=James D. |last16=Heming |first16=Julian |last17=Moskaitis |first17=Jonathan |last18=Komaromi |first18=William A. |last19=Ma |first19=Suhong |last20=Sampson |first20=Charles |last21=Wu |first21=Liguang |last22=Blake |first22=Eric |title=A review of recent advances (2018–2021) on tropical cyclone intensity change from operational perspectives, part 2: Forecasts by operational centers |journal=Tropical Cyclone Research and Review |date=March 2023 |volume=12 |issue=1 |pages=50–63 |doi=10.1016/j.tcrr.2023.05.003|doi-access=free |bibcode=2023TCRR...12...50W }} Intensity forecasting tools incorporating predictors for rapid intensification are also being developed and used in operations at other forecasting agencies such as the Korea Meteorological Administration and the Indian Meteorological Department.{{cite journal |last1=Courtney |first1=Joseph B. |last2=Langlade |first2=Sébastien |last3=Sampson |first3=Charles R. |last4=Knaff |first4=John A. |last5=Birchard |first5=Thomas |last6=Barlow |first6=Stephen |last7=Kotal |first7=S.D. |last8=Kriat |first8=Tarik |last9=Lee |first9=Woojeong |last10=Pasch |first10=Richard |last11=Shimada |first11=Udai |title=Operational Perspectives on Tropical Cyclone Intensity Change Part 1: recent advances in intensity guidance |journal=Tropical Cyclone Research and Review |date=September 2019 |volume=8 |issue=3 |pages=123–133 |doi=10.1016/j.tcrr.2019.10.002|doi-access=free |bibcode=2019TCRR....8..123C }}

{{see also|Tropical cyclones and climate change}}

The first working group report of the IPCC Sixth Assessment Report{{snd}}published in 2021{{snd}}assessed that the global occurrence of rapid intensification likely increased over the preceding four decades (during the period of reliable satellite data), with "medium confidence" in this change exceeding the effect of natural climate variability and thus stemming from anthropogenic climate change.{{cite book|last1=Seneviratne |first1=Sonia I. |last2=Zhang |first2=Xuebin |last3=Adnan |first3=Muhammad |last4=Badi |first4=Wafae |last5=Dereczynski |first5=Claudine |last6=Di Luca |first6=Alejandro |last7=Ghosh |first7=Subimal |last8=Iskandar |first8=Iskhaq |last9=Kossin |first9=James |last10=Lewis |first10=Sophie |last11=Otto |first11=Friederike |last12=Pinto |first12=Izidine |last13=Satoh |first13=Masaki |last14=Vicente-Serrano |first14=Sergio M. |last15=Wehner |first15=Masaki |last16=Zhou |first16=Botao |editor1-last=Masson-Delmotte |editor1-first=Valérie |editor2-last=Zhai |editor2-first=Panmao |editor3-last=Pirani |editor3-first=Anna |editor4-last=Connors |editor4-first=Sarah L. |editor5-last=Péan |editor5-first=Clotilde |editor6-last=Berger |editor6-first=Sophie |editor7-last=Caud |editor7-first=Nada |editor8-last=Chen |editor8-first=Yang |editor9-last=Goldfarb |editor9-first=Leah |editor10-last=Gomis |editor10-first=Melissa I. |editor11-last=Huang |editor11-first=Mengtian |editor12-last=Leitzell |editor12-first=Katherine |editor13-last=Lonnoy |editor13-first=Elisabeth |editor14-last=Matthews |editor14-first=J.B. Robin |editor15-last=Maycock |editor15-first=Thomas K. |editor16-last=Waterfield |editor16-first=Tim |editor17-last=Yelekçi |editor17-first=Ozge |editor18-last=Yu |editor18-first=Rong |editor19-last=Zhou |editor19-first=Baiquan |title=Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change |chapter=Weather and Climate Extreme Events in a Changing Climate |date=2021 |pages=1513–1766 |doi=10.1017/9781009157896.013 |publisher=Cambridge University Press |location=Cambridge, United Kingdom|isbn=978-1-009-15789-6 }}{{rp|pp=1519,1585}} The likelihood of a tropical cyclone with hurricane-force winds undergoing rapid intensification has increased from 1 percent in the 1980s to 5 percent.{{cite news |last1=Shao |first1=Elena |title=A 'Nightmare' for Forecasters: Here's Why Hurricanes Are Getting Stronger, Faster |url=https://www.nytimes.com/2022/09/26/climate/hurricane-ian-rapid-intensification.html |access-date=6 November 2023 |work=The New York Times |date=6 January 2023|orig-date=26 September 2022}} Statistically significant increases in the frequency of tropical cyclones undergoing multiple episodes of rapid intensification have also been observed since the 1980s.{{cite journal |last1=Manikanta |first1=N. D. |last2=Joseph |first2=Sudheer |last3=Naidu |first3=C. V. |title=Recent global increase in multiple rapid intensification of tropical cyclones |journal=Scientific Reports |date=September 2023 |volume=13 |issue=1 |page=15949 |doi=10.1038/s41598-023-43290-9|doi-access=free |pmid=37743385 |pmc=10518314 |bibcode=2023NatSR..1315949M }} These increases have been observed across the various tropical cyclone basins and may be associated with the thermodynamic properties of environments becoming increasingly conducive to intensification as a result of anthropogenic emissions. Reductions of wind shear due to climate change may also increase the probability of rapid intensification.{{cite journal |last1=Ting |first1=Mingfang |last2=Kossin |first2=James P. |last3=Camargo |first3=Suzana J. |last4=Li |first4=Cuihua |title=Past and Future Hurricane Intensity Change along the U.S. East Coast |journal=Scientific Reports |date=May 2019 |volume=9 |issue=1 |page=7795 |doi=10.1038/s41598-019-44252-w |pmid=31127128|doi-access=free |pmc=6534560 |bibcode=2019NatSR...9.7795T }} The frequency of rapid intensification within {{cvt|400|km}} of coastlines has also tripled between 1980 and 2020. This trend may be caused by a warming of coastal waters and a westward trend in the locations of peak tropical cyclone intensities stemming from broader changes to environmental steering flows.{{cite journal |last1=Li |first1=Yi |last2=Tang |first2=Youmin |last3=Wang |first3=Shuai |last4=Toumi |first4=Ralf |last5=Song |first5=Xiangzhou |last6=Wang |first6=Qiang |title=Recent increases in tropical cyclone rapid intensification events in global offshore regions |journal=Nature Communications |date=August 2023 |volume=14 |issue=1 |page=5167 |doi=10.1038/s41467-023-40605-2|doi-access=free |pmid=37620321 |pmc=10449825 |bibcode=2023NatCo..14.5167L }} A long-term increase in the magnitude of rapid intensification has also been observed over the Central and Tropical Atlantic as well as the western North Pacific.{{cite journal |last1=Balaguru |first1=Karthik |last2=Foltz |first2=Gregory R. |last3=Leung |first3=L. Ruby |title=Increasing Magnitude of Hurricane Rapid Intensification in the Central and Eastern Tropical Atlantic |journal=Geophysical Research Letters |date=May 2018 |volume=45 |issue=9 |pages=4238–4247 |doi=10.1029/2018GL077597|bibcode=2018GeoRL..45.4238B }}{{cite journal |last1=Song |first1=Jinjie |last2=Duan |first2=Yihong |last3=Klotzbach |first3=Philip J |title=Increasing trend in rapid intensification magnitude of tropical cyclones over the western North Pacific |journal=Environmental Research Letters |date=August 2020 |volume=15 |issue=8 |pages=084043 |doi=10.1088/1748-9326/ab9140|doi-access=free |bibcode=2020ERL....15h4043S }} However, CMIP5 climate projections suggest that environmental conditions in by the end of the 21st century may be less favorable for rapid intensification in all tropical cyclone basins outside of the North Indian Ocean.{{cite journal |last1=Walsh |first1=Kevin J.E. |last2=McBride |first2=John L. |last3=Klotzbach |first3=Philip J. |last4=Balachandran |first4=Sethurathinam |last5=Camargo |first5=Suzana J. |last6=Holland |first6=Greg |last7=Knutson |first7=Thomas R. |last8=Kossin |first8=James P. |last9=Lee |first9=Tsz-cheung |last10=Sobel |first10=Adam |last11=Sugi |first11=Masato |title=Tropical cyclones and climate change |journal=WIREs Climate Change |date=January 2016 |volume=7 |issue=1 |pages=65–89 |doi=10.1002/wcc.371|bibcode=2016WIRCC...7...65W |hdl=1721.1/62558 |hdl-access=free }}

{{Portal|Tropical cyclone}}

• List of the most intense tropical cyclones
• List of tropical cyclone records
• Annular tropical cyclone

{{Notelist}}

{{Reflist}}

{{Cyclones}}

{{DEFAULTSORT:Rapid deepening}}

Category:Tropical cyclone meteorology

Category:Weather hazards