Rapid intensification

Rapid intensification is a meteorological condition that occurs when a tropical cyclone intensifies dramatically in a short period of time. The United States National Hurricane Center defines rapid intensification as an increase in the maximum sustained winds of a tropical cyclone of at least 30 knots (35 mph; 55 km/h) in a 24-hour period.[1]

Maria RBTOP 2018-07-05 1330Z-2030Z
Infrared satellite loop of Typhoon Maria in July 2018, as it underwent rapid intensification

Necessary conditions


In order for rapid intensification to occur, several conditions must be in place. Water temperatures must be extremely warm (near or above 30 °C, 86 °F), and water of this temperature must be sufficiently deep such that waves do not churn deeper cooler waters up to the surface. Wind shear must be low; when wind shear is high, the convection and circulation in the cyclone will be disrupted[2]. Dry air can also limit the strengthening of tropical cyclones.[3]


Usually, an anticyclone in the upper layers of the troposphere above the storm must be present as well—for extremely low surface pressures to develop, air must be rising very rapidly in the eyewall of the storm, and an upper-level anticyclone helps channel this air away from the cyclone efficiently.[4] Hot towers have been implicated in tropical cyclone rapid intensification, though they have diagnostically seen varied impacts across basins.[5]

Previous nomenclature and definitions

The United States National Hurricane Center previously defined rapid deepening of a tropical cyclone, when the minimum central pressure decreased by 42 millibars (1.240 inHg) over a 24-hour period.[6] However it is now defined as an increase in the maximum sustained winds of a tropical cyclone of at least 30 knots (35 mph; 55 km/h) in a 24-hour period.[1]

See also


  1. ^ a b National Hurricane Center (March 25, 2013). "Glossary of NHC Terms". United States National Oceanic and Atmospheric Administration's National Weather Service. Archived from the original on April 1, 2014. Retrieved April 1, 2014.
  2. ^ Lam, Linda (October 23, 2015). "Multiple Factors Allowed Hurricane Patricia to Rapidly Intensify". The Weather Channel. Retrieved August 6, 2018.
  3. ^ Lam, Linda (7 September 2018). "Based on Hurricane Florence's Location, We Didn't Expect It to Get So Strong So Soon". The Weather Channel. Retrieved 7 September 2018.
  4. ^ Diana Engle. "Hurricane Structure and Energetics". Data Discovery Hurricane Science Center. Archived from the original on 2008-05-27. Retrieved 2008-10-26.
  5. ^ Zhuge, Xiao-Yong; Ming, Jie; Wang, Yuan (October 2015). "Reassessing the Use of Inner-Core Hot Towers to Predict Tropical Cyclone Rapid Intensification*". Weather and Forecasting. 30 (5): 1265–1279. Bibcode:2015WtFor..30.1265Z. doi:10.1175/WAF-D-15-0024.1.
  6. ^ National Hurricane Center/Tropical Prediction Center (February 7, 2005). "Glossary of NHC/TPC Terms". United States National Oceanic and Atmospheric Administration's National Weather Service. Archived from the original on October 17, 2005. Retrieved April 1, 2014.
Cyclone Ernie

Severe Tropical Cyclone Ernie was one of the quickest strengthening tropical cyclones on

record. Ernie was the first Category 5 severe tropical cyclone in the Australian region since Cyclone Marcia in 2015, and also the strongest tropical cyclone in the Australian region since Cyclone George in 2007. Ernie developed from a tropical low into a cyclone south of Indonesia in the northeast Indian Ocean on 6 April 2017, and proceeded to intensify extremely rapidly to a Category 5 severe tropical cyclone. A few days later, on 10 April, the system was downgraded below cyclone intensity following a period of rapid weakening (though not nearly as rapid as its intensification), located southwest of its original position. Ernie had no known impacts on any land areas.

February 1952 nor'easter

The February 1952 nor'easter was a significant winter storm that impacted the New England region of the United States. The storm ranked as Category 1, or "notable", on the Northeast Snowfall Impact Scale. Its rapid intensification resulted in heavy snowfall between February 17 and 18, accumulating to 12 to 30 inches (30 to 76 cm). High winds also affected central and northern New England. The nor'easter is estimated to have caused 42 fatalities. In Maine, over 1,000 travelers became stranded on roadways. Two ships cracked in two offshore New England during the storm.

Hurricane Adrian (2011)

Hurricane Adrian was an intense, albeit short-lived early-season category 4 hurricane that took part during the 2011 Pacific hurricane season. Adrian originated from an area of disturbed weather which had developed during the course of early June, off the Pacific coast of Mexico. On June 7, it acquired a sufficiently organized structure with deep convection to be classified as a tropical cyclone, and the National Hurricane Center (NHC) designated it as Tropical Depression One-E, the first one of 2011. It further strengthened to be upgraded into a tropical storm later that day. Adrian moved rather slowly; briefly recurving northward after being caught in the steering winds. After steady intensification, it was upgraded into a hurricane on June 9. The storm subsequently entered a phase of rapid intensification, developing a distinct eye with good outflow in all quadrants. Followed by this period of rapid intensification, it obtained sustained winds fast enough to be considered a major hurricane and reached its peak intensity as a category 4 hurricane that evening.

Adrian weakened throughout June 10 to June 12 as increased vertical wind shear persisted around its vicinity. It was downgraded into a tropical storm on June 11 as the once organized structure deteriorated, further so into a tropical depression the following day. Adrian subsequently decayed into a remnant low-pressure area with very little convection, all dislocated to the northeast of the low-level center. Degeneration continued and Adrian disintegrated into a swirl of low clouds, drifting due to the northwest. Since Adrian stayed at sea, its effects along coastlines were limited. Damages, if any, remains unknown, and no fatalities were reported as a result of the Adrian.

Hurricane Elida (2002)

Hurricane Elida was the first hurricane of the 2002 Pacific hurricane season to reach Category 5 strength on the Saffir-Simpson Hurricane Scale. Forming on July 23 from a tropical wave, the storm rapidly intensified from a tropical depression into a Category 5 hurricane in two days, and lasted for only six hours at that intensity before weakening. It was one of only sixteen known hurricanes in the East Pacific east of the International Date Line to have reached such an intensity. Although heavy waves were able to reach the Mexican coastline, no damages or casualties were reported in relation to the hurricane.

The hurricane moved westward due to a high pressure ridge while undergoing two eyewall replacement cycles: the first was around peak intensity and was completed when the hurricane moved over cooler waters, and the second was a brief cycle shortly after the hurricane began to weaken. The last advisory was issued while the hurricane was west of Mexico, but it was not until the remnants were west of Los Angeles, California that they finally dissipated. Elida's rapid intensification and unsteady weakening after reaching its peak intensity caused large errors in the intensity forecasting of the hurricane. Although the intensity forecasts were off, the track forecasts were better than usual compared to the ten-year period prior to that year.

Hurricane Emily (1987)

Hurricane Emily was the only major hurricane to develop during the below-average 1987 Atlantic hurricane season. Forming out of a tropical disturbance that moved off the west coast of Africa on September 20, the storm quickly attained hurricane status before undergoing rapid intensification. On September 22, the storm attained its peak intensity with winds of 125 mph (205 km/h) and a barometric pressure of 958 mbar (hPa; 28.29 inHg). The storm weakened slightly to Category 2 status before making landfall in the Dominican Republic. After weakening to a tropical storm, Emily rapidly tracked northeastward through the Atlantic Ocean, undergoing a second phase of rapid intensification before passing directly over Bermuda on September 25. The following day the final public advisory from the National Hurricane Center was issued on the storm as it transitioned into an extratropical cyclone.

Hurricane Emily brought heavy rains and strong winds in the Windward Islands on September 21, leaving numerous homes damaged and severe losses in the banana industry. Losses throughout the islands amounted to $291,000. In the Dominican Republic, despite the storm's high intensity, relatively moderate damage occurred. Three people were killed by the storm and damages amounted to $30 million. Unexpected intensification of the storm led to severe impact in Bermuda. The storm caused $50 million in damages and injured 16 people.

Hurricane Gilma (1994)

Hurricane Gilma was one of the most intense Pacific hurricanes on record and the second of three Category 5 hurricanes during the active 1994 Pacific hurricane season. Developing from a westward tracking tropical wave over the open waters of the eastern Pacific Ocean on July 21, the pre-Gilma tropical depression was initially large and disorganized. Gradual development took place over the following day before rapid intensification began. By July 23, the storm intensified into a hurricane and later a Category 5 storm on July 24. As Gilma reached this intensity, it crossed into the Central Pacific basin, the fourth consecutive storm to do so.

The storm peaked early on July 24 with winds of 160 mph (260 km/h) and a barometric pressure estimated at 920 mbar (hPa; 27.17 inHg). The following day, unknown factors caused the storm to suddenly weaken before increasing wind shear took over. The storm gradually weakened for the duration of its existence, turning slowly to the northwest. Late on July 28, the storm brushed Johnston Atoll, bringing gusty winds and light rainfall to the region. Gilma persisted until July 31 at which time it was downgraded to a tropical depression and dissipated over open waters.

Hurricane Guillermo (1997)

Hurricane Guillermo was the ninth-most intense Pacific hurricane on record, attaining peak winds of 160 mph (260 km/h) and a barometric pressure of 919 hPa (27.14 inHg). Forming out of a tropical wave on July 30, 1997, roughly 345 mi (555 km) south of Salina Cruz, Mexico, Guillermo tracked in a steady west-northwestward direction while intensifying. The system reached hurricane status by August 1 before undergoing rapid intensification the following day. At the end of this phase, the storm attained its peak intensity as a powerful Category 5 hurricane. The storm began to weaken during the afternoon of August 5 and was downgraded to a tropical storm on August 8. Once entering the Central Pacific Hurricane Center's area of responsibility, Guillermo briefly weakened to a tropical depression before re-attaining tropical storm status. On August 15, the storm reached an unusually high latitude of 41.8°N before transitioning into an extratropical cyclone. The remnants persisted for more than a week as they tracked towards the northeast and later south and east before being absorbed by a larger extratropical system off the coast of California on August 24.

Throughout Guillermo's track, the storm never threatened any major landmass, resulting in little impact on land. However, because of its extreme intensity, it produced large swells across the Pacific Ocean, affecting areas from Hawaii to coastal Mexico. Along the American Pacific coast, three people drowned amid high waves, two in Baja California and one in California. At its peak, Guillermo was the second strongest known Pacific hurricane on record; however, it has since been surpassed by seven other storms, including Linda later that year. The effects of Guillermo were not deemed severe enough to justify retirement of its name.

Hurricane Hilary (2011)

Hurricane Hilary was a powerful tropical cyclone that developed during the 2011 Pacific hurricane season. The fourth Category 4 and major hurricane, seventh hurricane, and eighth tropical storm of the season, Hilary developed from an area of low pressure off the Pacific coast of Central America in mid-September. Organizing quickly, the system became a tropical depression on September 21, after gaining enough organization to be declared as such. While moving towards the west-northwest, the depression continued to gather strength, and was subsequently upgraded to a tropical storm just several hours later. On September 21, Hilary was declared as a Category 1 hurricane, while located close to the Mexican coastline, where the storm brought heavy rainfall and flooding. Undergoing rapid intensification, Hilary strengthened into a Category 4 hurricane on September 22, recognized with a distinct eye feature. Beginning to enter cooler Ocean temperatures, Hilary began to weaken by September 25, but briefly restrengthened into a Category 4 the following day. Atmospheric conditions became increasingly unfavorable late on September 26, and the system began to weaken. During the afternoon hours of September 30, Hilary became a remnant low, while located several hundred miles away from any landmasses.

Hurricane Jova (2011)

Hurricane Jova was a strong Pacific hurricane that made landfall over Jalisco, Mexico. The tenth tropical depression and named storm, ninth hurricane, and fifth major hurricane of the 2011 Pacific hurricane season, Jova developed from an area of showers and thunderstorms that became better organized in early October. Moving towards the west-northwest, the area became better organized, and late on October 5, the National Hurricane Center began issuing advisories on Tropical Depression Ten-E. Steadily organizing, the storm was upgraded to Tropical Storm Jova later the following day, and by October 8, the storm had been classified as a Category 1 hurricane on the Saffir-Simpson hurricane scale. The storm attained Category 2 hurricane status late on October 9, and after a round of rapid intensification early on October 10, Jova had become a major hurricane.

Hurricane Julia

Hurricane Julia was the easternmost Category 4 hurricane recorded in the Atlantic basin since reliable satellite observations became available. The twelfth tropical cyclone, fifth hurricane and fourth major hurricane of the 2010 Atlantic hurricane season, Julia rapidly developed on September 12 from a tropical wave near Cape Verde. Passing near the islands, the system quickly organized into Tropical Storm Julia the next day. On September 14, Julia attained hurricane status and subsequently entered a trend of rapid intensification; the storm strengthened from a minimal hurricane to a low-end Category 4 in only 24 hours. After peaking in intensity, further development was impeded as interaction with nearby Hurricane Igor began to occur; the storm was downgraded to a tropical storm by September 18. It subsequently moved into a region of unfavorable conditions, heading toward lower sea surface temperatures. Correspondingly, Julia entered an extratropical transition on September 20, and advisories on the storm were discontinued by that time.

As Julia never posed any significant threat to land, damage related to the storm was minimal. Trace amounts of rain reportedly fell across the Cape Verde islands, causing locally light flooding and minor inconveniences. Gusts battering the territory peaked at 30 mph (48 km/h), resulting in some wind damage to crops. In addition, these winds produced rough sea conditions, and high waves posed few threats along coastlines.

Hurricane Rick (2009)

Hurricane Rick is the third-most intense Pacific hurricane on record. Developing south of Mexico on October 15, 2009, Hurricane Rick traversed an area favoring rapid intensification, allowing it to become a hurricane within 24 hours of being declared a tropical depression. An eye began to form during the afternoon of October 16; once fully formed, the storm underwent another period of rapid strengthening. During the afternoon of October 17, the storm attained Category 5 status on the Saffir–Simpson hurricane wind scale. Several hours later, Rick attained its peak intensity as the third-strongest Pacific hurricane on record with winds of 180 mph (285 km/h) and a barometric pressure of 906 mbar (hPa; 26.75 inHg).

After maintaining this intensity for several hours, Rick began to weaken in response to a combination of an eyewall replacement cycle and increasing wind shear. By October 19, the storm was downgraded to a Category 3 hurricane and the following day to a tropical storm. The long-anticipated northeast turn took place near the end of this phase, also accompanied by a brief decrease in forward motion. On October 21, Rick quickly moved northeast, brushing the tip of Baja California Sur before making landfall near Mazatlán with winds of 60 mph (97 km/h; 52 kn). Several hours after moving inland, the final advisory from the NHC was issued as the storm weakened to a tropical depression and dissipated.

Prior to landfall, the National Hurricane Center (NHC) initially forecast Rick to make landfall in southern Baja California as a high-end Category 2 hurricane, prompting hurricane watches. Officials ordered several hundred residents to evacuate from low-lying areas, although tropical storm warnings replaced the hurricane watches after the storm had weakened. Overall, the damage from Rick was significantly less than initially anticipated. In Mexico, three people were killed by the storm, one in Oaxaca and two in Baja California Sur.

Hurricane Uleki

Hurricane Uleki, also referred as Typhoon Uleki, was a long-lived tropical cyclone in August–September 1988 that had minimal effects on land. Originating from a disturbance in the Intertropical Convergence Zone in late-August, Uleki was identified as a tropical depression well to the southeast of Hawaii on August 28. Steady organization ensued as it moved west, becoming a tropical storm on August 30 and a hurricane on August 31. Rapid intensification took place thereafter and the storm reached its peak intensity on September 2 as a Category 3 on the Saffir–Simpson hurricane wind scale. Hurricane Hunters investigating the cyclone found peak winds of 125 mph (205 km/h) and a barometric pressure of 957 mbar (hPa; 28.26 inHg). Thereafter, Uleki stalled for two days to the southwest of Hawaii, resulting in heavy surf across the state. The dangerous swells killed two people on Oahu.

Unfavorable environmental conditions caused weakening of the hurricane by September 4 as it resumed a west-northwest course away from Hawaii. Conditions later became favorable and Uleki acquired winds of 105 mph (165 mph) on September 7, constituting its secondary peak. The hurricane crossed the International Dateline on September 8 and was reclassified as typhoon. Remaining well away from land, the cyclone steadily weakened to a tropical storm by September 12. Gradually turning north and later east, the degrading cyclone transitioned into an extratropical cyclone four days later and ultimately dissipated on September 17 near the International Dateline.

Meteorological history of Hurricane Patricia

Hurricane Patricia was the most intense tropical cyclone ever recorded in the Western Hemisphere and the second-most intense worldwide in terms of barometric pressure. It also featured the highest one-minute maximum sustained winds ever recorded in a tropical cyclone. Originating from a sprawling disturbance near the Gulf of Tehuantepec in mid-October 2015, Patricia was first classified a tropical depression on October 20. Initial development was slow, with only modest strengthening within the first day of its classification. The system later became a tropical storm and was named Patricia, the twenty-fourth named storm of the annual hurricane season. Exceptionally favorable environmental conditions fueled explosive intensification on October 22. A well-defined eye developed within an intense central dense overcast and Patricia grew from a tropical storm to a Category 5 hurricane in just 24 hours—a near-record pace. The magnitude of intensification was poorly forecast and both forecast models and meteorologists suffered from record-high prediction errors.

On October 23, two Hurricane Hunter missions both revealed the storm to have acquired maximum sustained winds of 205 mph (335 km/h) and a pressure of 879 mbar (hPa; 25.96 inHg). Since the peak intensity was assessed to have occurred between the missions, the National Hurricane Center ultimately estimated Patricia to have acquired winds of 215 mph (345 km/h) and pressure of 872 mbar (hPa; 25.75 inHg). This ranked it just below Typhoon Tip of 1979 as the most intense tropical cyclone on record. Patricia's exceptional intensity prompted the retirement of its name in April 2016. Late on October 23, Patricia made landfall in a significantly weakened state near Cuixmala, Jalisco. Despite weakening greatly, it was the strongest landfalling Pacific hurricane with winds estimated at 150 mph (240 km/h). Interaction with the mountainous terrain of Mexico induced dramatic weakening, faster than the storm had intensified. Within 24 hours of moving ashore, Patricia degraded into a tropical depression and dissipated soon thereafter late on October 24.

Typhoon Elsie (1989)

Typhoon Elsie, known in the Philippines as Typhoon Tasing, was one of the most intense known tropical cyclones to make landfall in the Philippines. A powerful Category 5 super typhoon, Elsie formed out of a tropical disturbance on October 13, 1989, and initially moved relatively slowly in an area of weak steering currents. On October 15, the storm underwent a period of rapid intensification, attaining an intensity that corresponds to a Category 3 hurricane on the Saffir–Simpson Hurricane Scale. After taking a due west track towards the northern Philippines, the storm intensified further, becoming a Category 5 super typhoon hours before making landfall in Luzon. After moving inland, the typhoon rapidly weakened to a tropical storm. Once back over water in the South China Sea, wind shear prevented re-intensifcation. Elsie eventually made landfall in Vietnam on October 22 and dissipated the following day over Laos.

In the Philippines, Elsie worsened the situation already left in the wakes of typhoons Angela and Dan. Although it was stronger than the previous two, Elsie caused far less damage due to the relatively sparse population in the area of landfall. During the storm's passage, 47 people were killed and another 363 were injured. Damages throughout the country amounted to $35.4 million and roughly 332,000 people were left homeless.

Typhoon Keith

Typhoon Keith was the tenth of a record eleven super typhoons to develop during the unusually intense 1997 Pacific typhoon season. Originating from a near-equatorial trough on October 26, the precursor depression to Keith slowly organized into a tropical storm. After two days of gradual strengthening, the storm underwent a period of rapid intensification on October 30 as winds increased to 195 km/h (120 mph). On November 1, the storm further intensified into a super typhoon and later attained peak winds of 285 km/h (180 mph). The following day, the powerful storm passed between Rota and Tinian in the Northern Mariana Islands. After fluctuating in strength over the following few days, a steady weakening trend established itself by November 5 as the typhoon accelerated towards the northeast. On October 8, Keith transitioned into an extratropical cyclone and was last noted early the following day near the International Dateline.

Despite Typhoon Keith's close passage to the islands of Rota and Tinian as a powerful storm, neither island received sustained winds over 160 km/h (105 mph). However, these winds resulted in significant damage across the island chain. More than 800 homes were damaged or destroyed by the storm and losses amounted to $15 million (1997 USD). There were no reports of fatalities in relation to the storm; however, one person was injured.

Typhoon Maria (2018)

Typhoon Maria, known in the Philippines as Typhoon Gardo, was a powerful tropical cyclone that affected Guam, Taiwan, and China. Developing into the eighth named tropical storm of the northwest Pacific Ocean and impacting the Mariana Islands on July 4, Maria strengthened into the fourth typhoon of this season and underwent extremely rapid intensification the next day, due to favorable environmental conditions. The typhoon reached its first peak intensity on July 6; subsequently, Maria weakened due to an eyewall replacement cycle, but it re-intensified and reached its second peak intensity on July 8. Later, it started to gradually weaken due to colder sea surface temperatures. After hitting the Yaeyama Islands and affecting Taiwan on July 10, Maria ultimately made landfall over Fujian, China, early on July 11, before dissipating on the next day.

Typhoon Meranti (2004)

Typhoon Meranti was the first of the record nine named storms to develop during August within the 2004 Pacific typhoon season. Forming from an area of low pressure on August 3, Meranti gradually strengthened. On August 5, the storm underwent a brief period of rapid intensification, attaining its peak intensity later that day. According to the Japan Meteorological Agency, the storm attained winds of 140 km/h (85 mph 10-minute winds) while the Joint Typhoon Warning Center reported that the storm attained winds of 165 km/h (105 mph 1-minute winds). The following day, the typhoon quickly weakened to a tropical storm due to unfavorable conditions. By August 9, the system completed an extratropical transition; the remnants of the storm persisted until August 13, at which time it was absorbed by a large, non-tropical low.

Typhoon Rita (1978)

Super Typhoon Rita, known in the Philippines as Typhoon Kading, was the most powerful tropical cyclone during the 1978 Pacific typhoon season and one of the most intense tropical cyclones on record. A long-lived and destructive tropical cyclone, Rita began its journey east of the Marshall Islands and rapidly moved westwards, becoming a typhoon on October 20. Rita continued rapid intensification and attained super typhoon status and later an atmospheric pressure of 878 mbar (25.9 inHg) on October 25. Rita struck the Philippines overnight on October 26 and entered the South China Sea as a minimal typhoon. Rita caused extreme damage and more than 300 deaths.

Typhoon Wutip (2019)

Typhoon Wutip, known in the Philippines as Tropical Depression Betty, was the most powerful February typhoon on record, surpassing Typhoon Higos of 2015. The third tropical cyclone, second tropical storm, and the first typhoon of the 2019 Pacific typhoon season, Wutip originated from a low-pressure area on February 16, 2019. The disturbance moved westward, passing just south of the Federated States of Micronesia, before later organizing into Tropical Depression 02W on February 18, 2019. On February 20, 2019, the tropical depression intensified into a tropical storm and was named Wutip, before strengthening further into a typhoon on the next day. Wutip underwent rapid intensification, and on February 23, Wutip reached its initial peak intensity, with 10-minute sustained winds of 185 km/h (115 mph), 1-minute sustained winds of 250 km/h (155 mph), and a minimal pressure of 925 millibars (27.3 inHg) while passing to the southwest of Guam, becoming the strongest February typhoon on record as it did so.

Wutip underwent an eyewall replacement cycle shortly afterward, which caused the storm to weaken as it turned to the northwest. Wutip finished its eyewall replacement cycle on February 24, which allowed Wutip to restrengthen, with the typhoon rapidly intensifying once again. On February 25, Wutip reached its peak intensity with 10-minute sustained winds of 195 km/h (120 mph), 1-minute sustained winds of 260 km/h (160 mph), and a minimum central pressure of 920 millibars (27 inHg), becoming the first Category 5-equivalent super typhoon recorded in the month of February. Afterward, Wutip weakened on February 26, due to encountering strong wind shear. Wutip rapidly weakened as it moved northwestward, before dissipating on March 2.

Wutip caused at least $3.3 million (2019 USD) in damages in Guam and Micronesia.



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