In February, 1982, The Journal of the Atmospheric Sciences published a ground-breaking study by Hugh Willoughby, Jean Clos, and Mohammed Shoreibah on what became to be known as the eyewall replacement cycle. Using data obtained from NOAA P3 flights into very intense Hurricanes Anita, David and Allen, they found that a common feature of intense tropical cyclones was a second ring of convection around the primary eyewall and that this second ring also had a wind-speed maximum. This second ring contracts while starving the inner ring of moisture and energy, so the second ring eventually replaces the first one as the eyewall, and the process can repeat. They also found that the appearance of the second ring marks the end of a period of intensification, enabling improved intensity forecasts.
This historic paper can be found at http://journals.ametsoc.org/doi/pdf/10.1175/1520-0469%281982%29039%3C0395%3ACEWSWM%3E2.0.CO%3B2.
Posted in HFIP-Hurricane Forecast Improvement Project, Modeling and Prediction, Observations, Publications
Tagged Eyewall replacement cycle, History, Hugh Willoughby, Hurricane Allen, Hurricane Anita, Hurricane David, J. A. Clos, M. G. Shoreibah, P3, Typhoon Bess, Typhoon Billie, Typhoon Georgia, Typhoon Irma, Typhoon Patsy
In October 2015, off the west coast of Mexico, Hurricane Patricia became the strongest hurricane ever recorded in the western hemisphere, intensifying faster than any other storm on record. A unique set of observations were collected in Patricia. National Oceanic and Atmospheric Administration (NOAA) and National Aeronautics and Space Administration/Office of Naval Research (ONR) aircraft flew into and above Patricia from its birth to landfall in Mexico, and on-the ground measurements were obtained during Patricia’s landfall. This paper summarizes the life of Patricia and the observations gathered.
Important Conclusions: (two – three)
- NOAA and ONR aircraft flew into and above Patricia during its entire lifetime, providing unprecedented views of Patricia’s wind, temperature, and moisture from the ocean surface to above the top of the storm. Storm chasers in the path of Patricia’s landfall also collected surface pressure measurements.
- These observations showed that Hurricane Patricia was a historic storm that broke many records:
|Fastest 10-s sustained surface wind speed measured by aircraft
||94 m s-1 (182 kt; 210 mph)
|Fastest 10-s flight-level wind speed measured by aircraft
||99 m s-1 (192 kt; 221 mph) (tied with Supertyphoon Megi 2010)
|Lowest minimum pressure measured by aircraft
||879 mb (25.96 in)
|Warmest 700-hPa temperature measured by aircraft
||32.2° C (90° F)
|Fastest best-track maximum sustained wind speed
||95 m s-1 (185 kt; 213 mph)
|Lowest best-track minimum pressure
||872 hPa (25.75 in)
|Most rapid best-track intensification rate
||97 hPa (2.86 in), 54 m s-1 (105 kt; 120 mph) in 24 h
(97 hPa in 24 h ties Hurricane Wilma 2005)
|Most rapid over-water weakening rate
||54 hPa (1.59 in), 26 m s-1 (50 kt; 57.5 mph) in 5 h
|Strongest updraft measured by dropsonde
||27.4 m s-1 (53 kt; 61 mph)
|Highest Advanced Dvorak Technique T-number
||T8.4 (94 m s-1;182 kt; 210 mph)
- The data will be used to study what caused this record-breaking storm, and will help to improve forecasts of these systems.
Posted in HFIP-Hurricane Forecast Improvement Project, Impacts, Modeling and Prediction, Observations, Publications
Tagged Doppler radar, dropwindsondes, Hurricane Ensemble Data Assimilation System (HEDAS), Hurricane Patricia, landfall, P3, rapid intensity change, Robert F. Rogers, Sim D. Aberson
Dr. Robert Burpee
In the January 1972 issue of the Journal of Atmospheric Science, Robert W. Burpee (future director of HRD) published a paper explaining the mechanism by which African Easterly Waves (AEW) formed. Using five years of upper-air data from above Africa, he demonstrated that airflow over the Ethiopian highlands created instabilities in the wind stream that moved downwind over the Atlantic Ocean. These waves are regular features of the tropical Atlantic during the summer and early fall and spawn roughly half of the tropical cyclones that form in the Atlantic, and many others in the Eastern Pacific.
The paper has been cited over 100 times and has been greatly influential in meteorologists’ understanding of tropical-wave formation.
1972: The Origin and Structure of Easterly Waves in the Lower Troposphere of North Africa. J. Atmos. Sci., 29, 77–90, doi: 10.1175/1520-0469(1972)029<0077:TOASOE>2.0.CO;2.
Hurricane Sandy transitions to hybrid system as it approaches New York
In 2017 we will be observing the following tropical cyclone-related anniversaries:
2012 5th anniversary
- Hurricane Sandy brings great destruction to the Caribbean, Bahamas, and northeastern US. It causes $75 billion in damage, making it the second costliest Atlantic storm on record.
- Hurricane Ernesto is responsible for 12 deaths and about $252 million in damage in Mexico.
- Typhoon Bopha (Pablo) kills over 1000 in the Philippines.
- Typhoon Vicente hits the Philippines, China, Vietnam, Laos, and Myanmar.
2007 10th anniversary
- Hurricane Dean hits just north of the Belize/Mexico border as a Category-5 hurricane.
- Hurricane Felix rapidly intensifies in the Caribbean and smashes into northern Nicaragua at Category-5 strength. This was the first time on record that two Category-5 hurricanes made landfall during the same Atlantic hurricane season.
- Hurricane Humberto reaches hurricane strength just before making landfall in northern Texas and only 11 hours after being named a tropical storm.
- An Aerosonde is flown into an Atlantic hurricane for the first time in Noel off the Carolina coast.
- Severe Tropical Cyclone Guba hit Papua New Guinea killing 492.
2002 15th anniversary
- Hurricane Isidore hits Yucatan and Louisiana, causing $1.3 billion in damage.
- Hurricane Lili strikes Louisiana leaving $925 million in destruction and 15 dead.
- Typhoon Chataan (Gloria) becomes the deadliest disaster to strike Chuuk, killing 48. It also strikes Guam and Japan.
- Typhoon Rusa hits South Korea, causing at least 238 deaths.
- Elida, Hernan, and Kenna mark the first time three Category-5 hurricanes occur in the Eastern Pacific in one season.
- Super Typhoon Pongsona hit the Mariana Islands.
1997 20th anniversary
- NOAA’s G-IV high altitude jet becomes operational, allowing examination of the steering flow around hurricanes from a greater height.
- High-resolution GPS dropsondes are released in the eyewall of Hurricane Guillermo in the Eastern Pacific. These reveal vertical wind structure that surprise scientists.
- Super Typhoon Paka ravages Guam causing $500 million in damage.
- Hurricane Linda is the strongest Eastern Pacific hurricane until Patricia (2015).
- Hurricane Pauline killed 230-500 in Oaxaca and is the easternmost Category-4 hurricane in the Eastern Pacific.
1992 25th anniversary
- Hurricane Andrew strikes the Bahamas, south Florida, and Louisiana, causing $26 billion in damages.
- NCEP’s Aviation model becomes operational.
- Super Typhoon Omar hits Guam causing $561 million in damage.
- Hurricane Iniki plows into Kauai as a Category-4 storm.
- Tropical Cyclone Motion-92 Experiment combines satellite and aircraft observations to study tropical cyclogenesis.
1987 30th anniversary
- The Air Force disbands its Pacific Typhoon Chasers squadrons.
- Severe Tropical Cyclone Uma killed 50 in Vanuatu.
- Supertyphoon Nina (Sisang) hit the Philippines killing 1036.
- Supertyphoon Betty (Herming) hit the Philippines killing 94.
1982 35th anniversary
- The first Synoptic Flow experiment is flown around Hurricane Debby, releasing dropsondes to help define the large-scale atmospheric winds that steer the storm.
- Richard Anthes publishes “Tropical Cyclones, Their Evolution, Structure, and Effects.”
- Hugh Willoughby, Jean Clos, and Mohamed Shoreibah publish a paper on hurricane eyewall replacement cycles.
- Tropical Storm Aletta hit Central America killing 308.
- Hurricane Paul hit El Salvador, Guatemala, and Mexico killing 1696.
- Super Typhoon Bess hit Japan as a tropical storm, but caused 95 fatalities and $2.3 billion in damage.
- Hurricane Iwa hit Hawaii.
1977 40th anniversary
- Andhra Pradesh cyclone in India kills over 14,000 people.
- Category-5 Hurricane Anita makes landfall in Mexico.
1972 45th anniversary
- Charlie Neumann develops CLIPER, a statistical hurricane track forecast scheme. It is used as a benchmark for other model’s forecast skill.
- Roland Madden and Paul Julian describe a global-scale pressure wave which seems to enhance tropical convection, what becomes known as the Madden-Julian Oscillation (MJO).
- Hurricane Agnes floods areas along the US eastern seaboard causing over 120 deaths and over $2 billion in damage, making it the most destructive hurricane in the US to that time.
- Bob Burpee publishes a paper explaining the origin and structure of African easterly waves.
- Severe Tropical Cyclone Bebe killed 24 in Tuvalu and Fiji.
1967 50th anniversary
- The US Air Force joins Project STORMFURY.
- The Miami hurricane warning center is separated from the local weather forecast office and officially reorganized as the National Hurricane Center.
- Hurricane Beulah winds its way through the Caribbean Sea and Gulf of Mexico, causing $1 billion in damage and killing 688 people. As it passes south of Puerto Rico, its eyewall replacement cycle is recorded by the Weather Bureau radar.
- Supertyphoon Emma (Welming) hit the Philippines killing 300.
1962 55th anniversary
- Project STORMFURY is formally organized. It’s a joint Navy – Weather Bureau experiment to test the hypothesis that seeding hurricanes with silver iodide will reduce the force of the winds.
- Supertyphoon Karen hit Guam, the strongest storm ever to strike that island.
1957 60th anniversary
- Hurricane Audrey strikes Louisiana and causes about 500 deaths.
1952 65th anniversary
- The Groundhog Day storm becomes the only Atlantic tropical cyclone on record for the month of February.
1947 70th anniversary
- The US Navy and General Electric seed a hurricane off Georgia as part of Project Cirrus. The hurricane later makes a u-turn and strikes Savannah.
- Bob Simpson carries out ‘piggyback’ mission into a hurricane off Florida. This is the first scientific examination of the upper-levels of a hurricane.
- A Category-4 hurricane floods South Florida.
1932 85th anniversary
- A major hurricane strikes Cuba in early November, causing over 3000 deaths on the island, the deadliest storm ever to hit the island. This was the latest Category-5 during hurricane season on record.
- Great Abaco Hurricane makes landfall as a Category-5 hurricane.
1927 90th anniversary
- The Great August Gale smacks into Nova Scotia, causing over 170 deaths and $1.5 million in damage.
1922 95th anniversary
- Edward Bowie observes that most hurricanes move anti-cyclonically around the subtropical ridge.
1917 100th anniversary
- The Nueva Gerona hurricane devastates the Isle of Pines and western Cuba, killing 35 and causing over $2 million in damage. It was the strongest hurricane to hit the Florida panhandle until Hurricane Opal in 1995.
1912 105th anniversary
- A cyclone sinks the SS Koombana off W. Australia killing 149.
1902 115th anniversary
- US Weather Bureau moves its hurricane warning center from Havana to Washington DC.
1897 130th anniversary
- Fr. José Algué publishes a book cataloging and categorizing typhoon tracks.
1882 135th anniversary
- Bombay Cyclone killed 100,000
1877 140th anniversary
- Viñes publishes “Relative Points of the Hurricanes of the Antilles in September and October of 1875 and 1876,” in which he details using waves and cloud motions to forecast hurricanes.
1847 170th anniversary
- Col. Reid establishes a hurricane warning system at Barbados.
1837 180th anniversary
- Racer’s Hurricane devastates much of the Gulf coast.
1782 235th anniversary
- A maritime disaster in Central Atlantic due to hurricane kills > 3000.
1767 250th anniversary
- Martinique Hurricane kills 1600.
1737 280th anniversary
- Calcutta Cyclone killed 300,000.
1667 350th anniversary
- The Dreadful Hurricane strikes the Virginia colonies.
1622 395th anniversary
- A hurricane in Florida Straits kills 1090.
1502 515th anniversary
- During his fourth voyage, Christopher Columbus warns the governor of Santo Domingo of an approaching hurricane but is ignored. A Spanish treasure fleet sets sail and loses 20 ships with 500 men.