NationMaster - Encyclopedia: Structure of tropical cyclones

The eye is a region of mostly calm weather found at the center of strong tropical cyclones. The eye of a storm is usually circular and typically 30–65 km (20–40 mi) in diameter. It is surrounded by the eyewall, where the most severe weather of a cyclone occurs. The cyclone's lowest barometric pressure occurs in the eye, and can be as much as 15% lower than the atmospheric pressure outside the storm. The distance between the center of the eye and eyewall defines the radius of maximum wind for a tropical cyclone. Cyclone Catarina, a rare South Atlantic tropical cyclone viewed from the International Space Station on March 26, 2004 Hurricane and Typhoon redirect here. ... km redirects here. ... A mile is any of several units of distance, or, in physics terminology, of length. ... DIAMETER is an AAA protocol (Authentication, Authorization and Accounting) succeeding its predecessor RADIUS. // The name is a pun on the RADIUS protocol, which is the predecessor (a diameter is twice the radius). ... Atmospheric pressure is the pressure caused by the weight of air above any area in the Earths atmosphere. ... The radius of maximum wind, or RMW, of a tropical cyclone is defined to be the distance between the center of the cyclone and its band of strongest winds. ...

The eye is possibly the most recognizable feature of tropical cyclones. Surrounded by the eyewall, a ring of towering thunderstorms, the eye is a roughly-circular area at the cyclone's center of circulation. In strong tropical cyclones, the eye is characterised by light winds and clear skies, surrounded on all sides by a towering, symmetric eyewall. In weaker tropical cyclones, the eye is less well-defined, and can be covered by the central dense overcast, which is an area of high, thick clouds which show up brightly on satellite pictures. Weaker or disorganized storms may also feature an eyewall which does not completely encircle the eye, or have an eye which features heavy rain. In all storms, however, the eye is the location of the storm's minimum barometric pressure: the area where the atmospheric pressure at sea level is the lowest.^[1]^[2] A shelf cloud associated with a heavy or severe thunderstorm over Enschede, The Netherlands. ... Radar image of a tropical cyclone in the northern hemisphere. ... This article or section does not adequately cite its references or sources. ... Cumulonimbus capillatus incus floating over Swifts Creek, Victoria in Australia A cloud is a visible mass of condensed droplets or frozen crystals suspended in the atmosphere above the surface of the Earth or another planetary body. ... NASA Goddard Space Flight Center Image Satellite imagery consists of photographs of Earth or other planets made from artificial satellites. ... Rain is a source of precipitation which forms when separate drops of water fall to the Earths surface from clouds. ... Diurnal (daily) rhythm of air pressure in northern Germany (black curve is air pressure) Atmospheric pressure is the pressure at any point in the Earths atmosphere. ...

Structure

A typical tropical cyclone will have an eye approximately 30–65 km (20–40 mi) across, usually situated at the geometric center of the storm. The eye may be clear or have spotty low clouds (a clear eye), it may be filled with low- and mid-level clouds (a filled eye), or it may be obscured by the central dense overcast. There is, however, very little wind and rain, especially near the center. This is in stark contrast to conditions in the eyewall, which contains the storm's strongest winds.^[3] Due to the mechanics of a tropical cyclone, the eye and the air directly above it are warmer than their surroundings.^[4] A 3-D view of a beverage-can stove with a cross section in yellow. ... Cumulonimbus capillatus incus floating over Swifts Creek, Victoria in Australia A cloud is a visible mass of condensed droplets or frozen crystals suspended in the atmosphere above the surface of the Earth or another planetary body. ... Cyclone Catarina, a rare South Atlantic tropical cyclone viewed from the International Space Station on March 26, 2004 Hurricane and Typhoon redirect here. ...

While normally quite symmetric, eyes can be oblong and irregular, especially in weakening storms. A large ragged eye is a non-circular eye which appears fragmented, and is an indicator of a weak or weakening tropical cyclone. An open eye is an eye which can be circular, but the eyewall does not completely encircle the eye, also indicating a weakening, moisture-deprived cyclone. Both of these observations are used to estimate the intensity of tropical cyclones via Dvorak analysis.^[5] The Dvorak Technique (developed in 1974 by Vernon Dvorak) is a widely used system to estimate tropical cyclone intensity based solely on visible and infrared satellite images. ...

While typical mature storms have eyes that are a few dozen miles across, rapidly intensifying storms can develop an extremely small, clear, and circular eye, sometimes referred to as a pinhole eye. Storms with pinhole eyes are prone to large fluctuations in intensity, and provide difficulties and frustrations for forecasters.^[6] Hurricane Charley nearing landfall after its rapid deepening phase Rapid deepening is when the minimum sea-level pressure of a tropical cyclone decreases drastically in a short period of time. ...

Small eyes—those less than 10 nmi (19 km, 12 mi) across—often trigger eyewall replacement cycles, where a new eyewall begins to form outside the original eyewall. This can take place anywhere from ten to a few hundred miles (fifteen to hundreds of kilometers) outside the inner eye. This results in the storm having two concentric eyewalls, or an "eye within an eye". In most cases, the outer eyewall contracts soon after its formation, choking off the inner eye, and creating a much larger, but stable eye. While this process tends to weaken storms as it occurs, the new eyewall can contract fairly quickly after the old eyewall dissipates, causing the storm to re-strengthen and the process to repeat. The contracted new eyewall may trigger another cycle of eyewall replacement.^[7] ImageMetadata File history File links Download high resolution version (4000x3000, 3731 KB) Summary Hurricane Nate on September 6, 2005 Licensing File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... ImageMetadata File history File links Download high resolution version (4000x3000, 3731 KB) Summary Hurricane Nate on September 6, 2005 Licensing File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Lowest pressure 979 mbar (hPa; 28. ... September 6 is the 249th day of the year (250th in leap years). ... 2005 (MMV) was a common year starting on Saturday of the Gregorian calendar. ... A nautical mile or sea mile is a unit of length. ... km redirects here. ... A mile is any of several units of distance, or, in physics terminology, of length. ...

Eyes can range in size from 320 km (200 miles) (Typhoon Carmen) to a mere 3 km (2 mi) (Hurricane Wilma) across.^[8] While it is uncommon for storms with large eyes to become very intense, it does occur, especially in annular hurricanes. Hurricane Isabel was the eleventh most powerful Atlantic hurricane of all time, and sustained a large, 65–80 km (40–50 mi)-wide eye for a period of several days.^[9] The 1960 Pacific typhoon season has no official bounds; it ran year-round in 1960, but most tropical cyclones tend to form in the northwestern Pacific Ocean between June and December. ... Lowest pressure 882 mbar (hPa) (Lowest pressure ever recorded in an Atlantic hurricane) Damage $28. ... Hurricane Isabel of 2003 showing annular hurricane structure. ... Hurricane Isabel was the ninth named storm, the fifth hurricane, the second major hurricane, and the only Category 5 hurricane of the 2003 Atlantic hurricane season. ... Atlantic hurricane refers to a tropical cyclone that forms in the Atlantic Ocean north of the equator, usually in the Northern Hemisphere summer or autumn. ...

Formation and detection

Tropical cyclones typically form from large, disorganized areas of disturbed weather in tropical regions. As more thunderstorms form and gather, the storm develops rainbands which start rotating around a common center. As the storm gains strength, a ring of stronger convection forms at a certain distance from the rotational center of the developing storm. Since stronger thunderstorms and heavier rain mark areas of stronger updrafts, the barometric pressure at the surface begins to drop, and air begins to build up in the upper levels of the cyclone.^[10] This results in the formation of an upper level anticyclone, or an area of high atmospheric pressure above the central dense overcast. Consequentially, most of this built up air flows outward anticyclonically above the tropical cyclone. Outside the forming eye, the anticyclone at the upper levels of the atmosphere enhances the flow towards the center of the cyclone, pushing air towards the eyewall and causing a positive feedback loop.^[10] Global Tropical Cyclone Tracks Cyclogenesis is the technical term describing the development or strengthening of a surface low pressure system, or cyclone, in the atmosphere. ... Positive feedback is a type of feedback. ... The tropics are the geographic region of the Earth centered on the equator and limited in latitude by the two tropics: the Tropic of Cancer in the northern hemisphere and the Tropic of Capricorn in the southern hemisphere. ... Cyclone Catarina, a rare South Atlantic tropical cyclone viewed from the International Space Station on March 26, 2004 Hurricane and Typhoon redirect here. ... Convection is the internal movement of currents within fluids (i. ... An Updraft or Downdraft is refers to the vertical movement of air as a weather related phenomenom. ... In meteorology, an anticyclone (i. ... Positive feedback is a type of feedback. ...

However, a small portion of the built-up air, instead of flowing outward, flows inward towards the center of the storm. This causes air pressure to build even further, to the point where the weight of the air counteracts the strength of the updrafts in the center of the storm. Air begins to descend in the center of the storm, creating a mostly rain-free area; a newly-formed eye.^[10]

There are many aspects of this process which remain a mystery. Scientists do not know why a ring of convection forms around the center of circulation instead of on top of it, or why the upper-level anticyclone only ejects a portion of the excess air above the storm. Hundreds of theories exist as to the exact process by which the eye forms: all that is known for sure is that the eye is necessary for tropical cyclones to achieve high wind speeds.^[10] Image File history File links HurricaneErin_Ozone_TOMS_2001sep12. ... Image File history File links HurricaneErin_Ozone_TOMS_2001sep12. ... Lowest pressure 968 mbar (hPa; 28. ... September 12 is the 255th day of the year (256th in leap years). ... 2001 (MMI) was a common year starting on Monday of the Gregorian calendar. ...

The formation of an eye is almost always an indicator of increasing tropical cyclone organisation and strength. Because of this, forecasters watch developing storms closely for signs of eye formation.

For storms with a clear eye, detection of the eye is as simple as looking at pictures from a weather satellite. However, for storms with a filled eye, or an eye completely covered by the central dense overcast, other detection methods must be used. Observations from ships and Hurricane Hunters can pinpoint an eye visually, by looking for a drop in wind speed or lack of rainfall in the storm's center. In the United States, a network of NEXRAD Doppler radar stations can detect eyes near the coast. Weather satellites also carry equipment for measuring atmospheric water vapor and cloud temperatures, which can be used to spot a forming eye. In addition, scientists have recently discovered that the amount of ozone in the eye is much higher than the amount in the eyewall, due to air sinking from the ozone-rich stratosphere. Instruments sensitive to ozone perform measurements, which are used to observe rising and sinking columns of air, and provide indication of the formation of an eye, even before satellite imagery can determine its formation.^[11] GOES-8, a United States weather satellite. ... The introduction to this article provides insufficient context for those unfamiliar with the subject matter. ... NEXRAD Radar at NSSL NEXRAD or Nexrad (Next-Generation Radar) is a network of 158 high-resolution Doppler radars operated by the National Weather Service, an agency of the National Oceanic and Atmospheric Administration (NOAA), in the United States. ... Doppler Effect Doppler radar uses the Doppler effect to measure the radial velocity of targets in the antennas directional beam. ... It has been suggested that multiple sections of steam be merged into this article or section. ... For other uses, see Ozone (disambiguation). ... NASA Goddard Space Flight Center Image Satellite imagery consists of photographs of Earth or other planets made from artificial satellites. ...

Associated phenomena

The 1997 Pacific typhoon season has no official bounds; it ran year-round in 1997, but most tropical cyclones tend to form in the northwestern Pacific Ocean between June and December. ...

Eyewall replacement cycles

Eyewall replacement cycles, also called concentric eyewall cycles, naturally occur in intense tropical cyclones, generally with winds greater than 185 km/h (115 mph), or major hurricanes (Category 3 or above). When tropical cyclones reach this threshold of intensity, and the eyewall contracts or is already sufficiently small (see above), some of the outer rainbands may strengthen and organize into a ring of thunderstorms—an outer eyewall—that slowly moves inward and robs the inner eyewall of its needed moisture and angular momentum. Since the strongest winds are located in a cyclone's eyewall, the tropical cyclone usually weakens during this phase, as the inner wall is "choked" by the outer wall. Eventually the outer eyewall replaces the inner one completely, and the storm can re-intensify. Cyclone Catarina, a rare South Atlantic tropical cyclone viewed from the International Space Station on March 26, 2004 Hurricane and Typhoon redirect here. ... The Saffir-Simpson Hurricane Scale is a scale classifying most Western Hemisphere tropical cyclones that exceed the levels of tropical depression and tropical storm and thereby become hurricanes; the categories it divides hurricanes into are distinguished by the intensities of their respective sustained winds. ... This gyroscope remains upright while spinning due to its angular momentum. ...

The discovery of this process was partially responsible for the end of the U.S. government's hurricane modification experiment Project Stormfury. This project set out to seed clouds outside the eyewall, causing a new eyewall to form and weakening the storm. When it was discovered that this was a natural process due to hurricane dynamics, the project was quickly abandoned.^[7] Project Stormfury was an attempt to weaken hurricanes by using cloud seeding in the eyewall of these storms. ... Cessna 210 with cloud seeding equipment Cloud seeding, a form of weather modification, is the attempt to change the amount or type of precipitation that falls from clouds, by dispersing substances into the air that serve as cloud condensation or ice nuclei. ...

Almost every intense hurricane undergoes at least one of these cycles during its existence. Hurricane Allen in 1980 went through repeated eyewall replacement cycles, fluctuating between Category 5 and Category 3 status on the Saffir-Simpson Scale several times. Hurricane Juliette (2001) was a rare documented case of triple eyewalls.^[12] Hurricane Allen was the strongest hurricane of the 1980 Atlantic hurricane season. ... The Saffir-Simpson Hurricane Scale is a scale classifying hurricanes by the intensity of their sustained winds, developed in 1969 by civil engineer Herbert Saffir and National Hurricane Center director Bob Simpson. ... Hurricane Juliette was a long lasting hurricane in the 2001 Pacific hurricane season. ...

Moats

A moat in a tropical cyclone is a clear ring outside the eyewall, or between concentric eyewalls, characterized by slowly sinking air, little or no precipitation, and strain-dominated flow.^[13] The moat between eyewalls is just one example of a rapid filamentation zone, or an area in the storm where the rotational speed of the air changes greatly in proportion to the distance from the storm's center. Such strain-dominated regions can potentially be found near any vortex of sufficient strength, but are most pronounced in strong tropical cyclones. Look up strain in Wiktionary, the free dictionary. ... Vortex created by the passage of an aircraft wing, revealed by coloured smoke A vortex (pl. ...

Eyewall mesovortices

Eyewall mesovortices are small scale rotational features found in the eyewalls of intense tropical cyclones. They are similar, in principle, to small "suction vortices" often observed in multiple-vortex tornadoes. In these vortices, wind speed can be up to 10% higher than in the rest of the eyewall. Eyewall mesovortices are most common during periods of intensification in tropical cyclones. Image File history File links Size of this preview: 800 Ã— 530 pixel Image in higher resolution (3032 Ã— 2008 pixel, file size: 646 KB, MIME type: image/jpeg) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): List of notable... Image File history File links Size of this preview: 800 Ã— 530 pixel Image in higher resolution (3032 Ã— 2008 pixel, file size: 646 KB, MIME type: image/jpeg) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): List of notable... Lowest pressure 882 mbar (hPa) (Lowest pressure ever recorded in an Atlantic hurricane) Damage $28. ... CDT is an abbreviation for carbohydrate deficient transferrin, a transporter protein isoform typically increased in alcoholism ConfÃ©dÃ©ration DÃ©mocratique du Travail, a trade union in the Democratic Republic of the Congo Continental Divide Trail Central Standard Time Zone Center for Democracy and Technology. ... ... October 19 is the 292nd day of the year (293rd in leap years) in the Gregorian calendar. ... 2005 (MMV) was a common year starting on Saturday of the Gregorian calendar. ... â€œISSâ€ redirects here. ... The bar (symbol bar) and the millibar (symbol mbar, also mb) are units of pressure. ... Inches of mercury or inHg is a non SI unit for pressure. ... A multiple vortex tornado is a tornado that contains several vortices rotating around and inside of and part of the main vortex. ...

Eyewall mesovortices often exhibit unusual behavior in tropical cyclones. They usually rotate around the low pressure center, but sometimes they remain stationary. Eyewall mesovortices have even been documented to cross the eye of a storm. These phenomena have been documented observationally,^[15] experimentally,^[16] and theoretically.^[17]

Eyewall mesovortices are a significant factor in the formation of tornadoes after tropical cyclone landfall. Mesovortices can spawn rotation in individual thunderstorms (a mesocyclone), which leads to tornadic activity. At landfall, friction is generated between the circulation of the tropical cyclone and land. This can allow the mesovortices to descend to the surface, causing large outbreaks of tornadoes. A tornado in central Oklahoma. ... It has been suggested that this article or section be merged into Supercell. ...

Stadium effect

The stadium effect is a phenomenon occasionally observed in strong tropical cyclones. It is a fairly common event, where the clouds of the eyewall curve outward from the surface with height. This gives the eye an appearance resembling an open dome from the air, akin to a sports stadium. An eye is always larger at the top of the storm, and smallest at the bottom of the storm because the rising air in the eyewall follows isolines of equal angular momentum, which also slope outward with height.^[18]^[19]^[20] This phenomenon refers to the characteristics of tropical cyclones with very small eyes, where the sloping phenomenon is much more pronounced. Telstra Stadium in Sydney, Australia is capable of being converted from a rectangular rugby football field to an oval for cricket and Australian rules football games This article is about the building type. ... It has been suggested that Isobar, Isobath, Isodrosotherm, Isogon, Isohel, Isohume, Isohyet, Isohypse, Isotach and Isotherm be merged into this article or section. ... This gyroscope remains upright while spinning due to its angular momentum. ...

Hazards

Though the eye is by far the calmest part of the storm, with no wind at the center and typically clear skies, over the ocean it is possibly the most hazardous area. In the eyewall, wind-driven waves are all traveling in the same direction. In the center of the eye, however, waves from all directions converge, creating erratic crests which can build on each other, creating rogue waves. The maximum height of hurricane waves is unknown, but new research indicates that typical hurricanes may have wave heights approaching 33 m (100 ft).^[21] This is in addition to any storm surge which may occur, as storm surges often extend into the eye. The Draupner wave, a single giant wave measured on New Years Day 1995, finally confirmed the existence of freak waves, which had previously been considered near-mythical Freak waves, also known as rogue waves or monster waves, are relatively large and spontaneous ocean surface waves which can sink even... ...

A common mistake, especially in areas where hurricanes are uncommon, is for residents to wander outside to inspect the damage while the eye passes over, thinking the storm is over. They are then caught completely by surprise by the violent winds in the opposite eyewall. The National Weather Service strongly discourages leaving shelter while the eye passes over.^[22] The National Weather Service (NWS) is one of the six scientific agencies that make up the National Oceanic and Atmospheric Administration (NOAA) of the United States government. ...

Other storms

Though only tropical cyclones have structures which are officially called "eyes", there are other storms which can exhibit eye-like structures: Radar image of a tropical cyclone in the northern hemisphere. ...

Polar lows

Polar lows are mesoscale weather systems (typically smaller than 1000 km or 600 miles across) found near the poles. Like tropical cyclones, they form over relatively warm water, can feature deep convection (thunderstorms), and feature winds of gale force or greater (≥ 51 km/h, 32 mph). Unlike storms of tropical nature, however, they thrive in much colder temperatures and at much higher latitudes. They are also smaller and last for shorter durations (few last longer than a day or so). Despite these differences, they can be very similar in structure to tropical cyclones, featuring a clear eye surrounded by an eyewall and rain/snow bands.^[23] Polar low over the Barents Sea on February 27, 1987 A polar low is a small-scale, short-lived atmospheric low pressure system (depression) that is found over the ocean areas poleward of the main polar front in both the Northern and Southern Hemispheres. ... Mesoscale Meteorology refers to weather systems smaller than synoptic scale systems but larger than storm-scale cumulus systems. ... ... Latitude, usually denoted symbolically by the Greek letter phi, , gives the location of a place on Earth north or south of the equator. ...

Extratropical storms

Extratropical storms are areas of low pressure which exist at the boundary of different air masses. Almost all storms found at mid-latitudes are extratropical in nature, including classic North American nor'easters and European windstorms. The most severe of these can have a clear "eye" at the site of lowest barometric pressure, though it is usually surrounded by lower, non-convective clouds and is found near the back end of the storm.^[24] Image File history File links Download high resolution version (740x776, 129 KB) File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Image File history File links Download high resolution version (740x776, 129 KB) File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... 1Maximum snowfall or ice accretion The Blizzard of 2006 was a noreaster that began on the evening of February 11, 2006. ... Delmarva Peninsula map The Delmarva Peninsula is a large peninsula on the East Coast of the United States, occupied by portions of three U.S. states: Delaware, Maryland, and Virginia. ... A fictitious synoptic chart of an extratropical cyclone affecting the UK & Ireland. ... In meteorology, an air mass is a large volume of air having fairly uniform characteristics of temperature, atmospheric pressure, and water vapor content. ... Satellite image of the intense noreaster responsible for the North American blizzard of 2006. ... A European windstorm is a severe cyclonic storm that tracks across the North Atlantic towards north-west Europe in the winter months. ...

Subtropical storms

Subtropical storms are cyclones which have some extratropical characteristics and some tropical characteristics. As such, they may have an eye, but are not true tropical storms. Subtropical storms can be very hazardous, with high winds and seas, and often evolve into true tropical storms. As such, the National Hurricane Center began including subtropical storms in their naming scheme in 2002.^[25] A subtropical cyclone is a weather system that has some characteristics of a tropical cyclone and some characteristics of an extratropical cyclone. ... National Weather Service Logo The U.S. National Hurricane Center is the division of National Weather Services Tropical Prediction Center responsible for tracking and predicting the likely behavior of tropical depressions, tropical storms and hurricanes. ...

Tornadoes

Tornadoes are destructive, small-scale storms, which produce the fastest winds on earth. There are two main types—single-vortex tornadoes, which consist of a single spinning column of air, and multiple-vortex tornadoes, which consist of small suction vortices, resembling mini-tornadoes themselves, all rotating around a common center. Both of these types of tornadoes are theorized to have calm centers, referred to by some meteorologists as "eyes". These theories are supported by doppler radar observations^[26] and eyewitness accounts.^[27] A tornado in central Oklahoma. ...

Extraterrestrial storms

NASA reported in November 2006 that the Cassini spacecraft observed a 'hurricane-like' storm locked to the south pole of Saturn that had a clearly defined eyewall. This observation is particularly notable because eyewall clouds have not been seen on any planet other than Earth (including a failure to observe an eyewall in the Great Red Spot of Jupiter by the Galileo spacecraft).^[28] The NASA worm logo. ... This article is about weather phenomena. ... Atmospheric characteristics Atmospheric pressure 140 kPa Hydrogen >93% Helium >5% Methane 0. ... The Great Red Spot is a persistent anticyclonic storm on the planet Jupiter, 22Â° south of the equator, which has lasted at least 340 years. ... Galileo is prepared for mating with the IUS booster Galileo being deployed after being launched by the Space Shuttle Atlantis on the STS-34 mission Galileo was an unmanned spacecraft sent by NASA to study the planet Jupiter and its moons. ...

See also

Image File history File links Download high resolution version (1000x662, 320 KB) http://eol. ... This is a list of notable tropical cyclones, subdivided by basin and reason for notability. ... The radius of maximum wind, or RMW, of a tropical cyclone is defined to be the distance between the center of the cyclone and its band of strongest winds. ... ... Cyclone Catarina, a rare South Atlantic tropical cyclone viewed from the International Space Station on March 26, 2004 Hurricane and Typhoon redirect here. ...

References

^ Landsea, Chris and Sim Aberson. (August 13, 2004). What is the "eye"?. Atlantic Oceanographic and Meteorological Laboratory. Retrieved on 2006 June 14.
^ Landsea, Chris. (October 19, 2005). What is a "CDO"?. Atlantic Oceanographic and Meteorological Laboratory. Retrieved on 2006 June 14.
^ National Weather Service (October 19, 2005). Tropical Cyclone Structure. JetStream - An Online School for Weather. National Oceanic & Atmospheric Administration. Retrieved on 2006 December 14.
^ Atlantic Oceanographic and Meteorological Laboratory, Hurricane Research Division. Frequently Asked Questions: What is an extra-tropical cyclone?. NOAA. Retrieved on 2007 March 23.
^ Objective Dvorak Technique. University of Wisconsin. Retrieved on 2006 May 29.
^ National Hurricane Center (October 8, 2005). Hurricane Wilma Discussion No. 14, 11:00 p.m. EDT. National Oceanic and Atmospheric Administration. Retrieved on 2006 June 12.
^ ^a ^b Atlantic Oceanographic and Meteorological Laboratory, Hurricane Research Division. Frequently Asked Questions: What are "concentric eyewall cycles" (or "eyewall replacement cycles") and why do they cause a hurricane's maximum winds to weaken?. NOAA. Retrieved on 2006 December 14.
^ Lander, Mark A. (1998). A Tropical Cyclone with a Very Large Eye. Monthly Weather Review: Vol. 127, pp. 137–142. Retrieved on 2006 June 14.
^ Beven, Jack and Hugh Cobb (2003). Hurricane Isabel Tropical Cyclone Report. National Hurricane Center. Retrieved on 2006 March 26.
^ ^a ^b ^c ^d Vigh, Jonathan (2006). Formation of the Hurricane Eye (PDF). Department of Atmospheric Science, Colorado State University. Retrieved on 2006 March 26.
^ "Ozone Levels Drop When Hurricanes Are Strengthening", NASA, June 8, 2005. Retrieved on 2006-05-09.
^ McNoldy, Brian D. (2004). Triple Eyewall in Hurricane Juliette. Bulletin of the American Meteorological Society: Vol. 85, pp. 1663-1666.
^ Rozoff, C. M., W. H. Schubert, B. D. McNoldy, and J. P. Kossin (2006). Rapid filamentation zones in intense tropical cyclones. Journal of the Atmospheric Sciences: Vol. 63, pp. 325-340.
^ Richard J. Pasch, Eric S. Blake, Hugh D. Cobb III, and David P. Roberts (January 12, 2006). Tropical Cyclone Report: Hurricane Wilma. National Hurricane Center.
^ Kossin, J. P., B. D. McNoldy, and W. H. Schubert (2002). Vortical swirls in hurricane eye clouds. Monthly Weather Review: Vol. 130, pp. 3144-3149.
^ Montgomery, M. T., V. A. Vladimirov, and P. V. Denissenko (2002). An experimental study on hurricane mesovortices. Journal of Fluid Mechanics: Vol. 471, pp. 1-32.
^ Kossin, J. P., and W. H. Schubert (2001). Mesovortices, polygonal flow patterns, and rapid pressure falls in hurricane-like vortices. Journal of the Atmospheric Sciences: Vol. 58, pp. 2196-2209.
^ Hawkins, H. F., and D. T. Rubsam (1968). Hurricane Hilda, 1964: II. Structure and budgets of the hurricane on October 1, 1964. Monthly Weather Review: Vol. 96, pp. 617-636.
^ Gray, W. M., and D. J. Shea (1973). The hurricane's inner core region: II. Thermal stability and dynamic characteristics. Journal of the Atmospheric Sciences: Vol. 30, pp. 1565-1576.
^ Hawkins, H. F., and S. M. Imbembo (1976). The structure of a small, intense hurricane - Inez 1966 (PDF). Monthly Weather Review: Vol. 104, pp. 418-442.
^ Carey, Bjorn (August 4, 2005). Hurricane's Waves Soared to Nearly 100 feet. LiveScience.com. Retrieved on 2006 March 26.
^ National Weather Service Southern Region Headquarters (January 6, 2005). Tropical Cyclone Safety. National Weather Service. Retrieved on 2006 August 6.
^ National Snow and Ice Data Center. Polar Lows. Retrieved on 2007 January 24.
^ Maue, Ryan N. (2006-04-25). Warm seclusion cyclone climatology. American Meteorological Society Conference. Retrieved on 2006 October 6.
^ Cappella, Chris (April 22, 2003). Weather Basics: Subtropical storms. USA Today. Retrieved on 2006 September 15.
^ Monastersky, R. (May 15, 1999). Oklahoma Tornado Sets Wind Record. Science News. Retrieved on 2006 September 15.
^ Justice, Alonzo A. (May 1930). Seeing the Inside of a Tornado (PDF). Monthly Weather Review 205-206. Retrieved on 2006 September 15.
^ NASA Sees into the Eye of a Monster Storm on Saturn. NASA (2006-11-09). Retrieved on 2006 November 10.

Christopher Landsea is a research meteorologist with Hurricane Research Division of Atlantic Oceanographic & Meteorological Laboratory at NOAA. He is a member of the American Geophysical Union and the American Meteorological Society. ... August 13 is the 225th day of the year in the Gregorian calendar (226th in leap years), with 140 days remaining. ... 2004 (MMIV) was a leap year starting on Thursday of the Gregorian calendar. ... The Atlantic Oceanographic and Meteorological Laboratory (AOML) is a laboratory in National Oceanic and Atmospheric Administrations Office of Oceanic and Atmospheric Research (OAR). ... For the Manfred Mann album, see 2006 (album). ... June 14 is the 165th day of the year in the Gregorian calendar (166th in leap years), with 200 days remaining. ... October 19 is the 292nd day of the year (293rd in leap years) in the Gregorian calendar. ... 2005 (MMV) was a common year starting on Saturday of the Gregorian calendar. ... The Atlantic Oceanographic and Meteorological Laboratory (AOML) is a laboratory in National Oceanic and Atmospheric Administrations Office of Oceanic and Atmospheric Research (OAR). ... For the Manfred Mann album, see 2006 (album). ... June 14 is the 165th day of the year in the Gregorian calendar (166th in leap years), with 200 days remaining. ... The National Weather Service (NWS) is one of the six scientific agencies that make up the National Oceanic and Atmospheric Administration (NOAA) of the United States government. ... October 19 is the 292nd day of the year (293rd in leap years) in the Gregorian calendar. ... 2005 (MMV) was a common year starting on Saturday of the Gregorian calendar. ... The National Oceanic and Atmospheric Administration (NOAA) is an agency of the United States Department of Commerce. ... For the Manfred Mann album, see 2006 (album). ... December 14 is the 348th day of the year (349th in leap years) in the Gregorian Calendar. ... The Atlantic Oceanographic and Meteorological Laboratory (AOML) is a laboratory in National Oceanic and Atmospheric Administrations Office of Oceanic and Atmospheric Research (OAR). ... The National Oceanic and Atmospheric Administration (NOAA) is a scientific agency of the United States Department of Commerce focused on the conditions of the oceans and the atmosphere. ... 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the Anno Domini (common) era. ... March 23 is the 82nd day of the year in the Gregorian calendar (83rd in leap years). ... For the Manfred Mann album, see 2006 (album). ... May 29 is the 149th day of the year in the Gregorian calendar (150th in leap years). ... The National Oceanic and Atmospheric Administration (NOAA) is a scientific agency of the United States Department of Commerce focused on the conditions of the oceans and the atmosphere. ... For the Manfred Mann album, see 2006 (album). ... June 12 is the 163rd day of the year in the Gregorian calendar (164th in leap years), with 202 days remaining. ... The Atlantic Oceanographic and Meteorological Laboratory (AOML) is a laboratory in National Oceanic and Atmospheric Administrations Office of Oceanic and Atmospheric Research (OAR). ... The National Oceanic and Atmospheric Administration (NOAA) is a scientific agency of the United States Department of Commerce focused on the conditions of the oceans and the atmosphere. ... For the Manfred Mann album, see 2006 (album). ... December 14 is the 348th day of the year (349th in leap years) in the Gregorian Calendar. ... For the Manfred Mann album, see 2006 (album). ... June 14 is the 165th day of the year in the Gregorian calendar (166th in leap years), with 200 days remaining. ... National Weather Service Logo The U.S. National Hurricane Center is the division of National Weather Services Tropical Prediction Center responsible for tracking and predicting the likely behavior of tropical depressions, tropical storms and hurricanes. ... For the Manfred Mann album, see 2006 (album). ... March 26 is the 85th day of the year in the Gregorian calendar (86th in leap years). ... Colorado State University is a public land grant institution of higher learning located in Fort Collins, Colorado in the United States. ... For the Manfred Mann album, see 2006 (album). ... March 26 is the 85th day of the year in the Gregorian calendar (86th in leap years). ... The NASA worm logo. ... June 8 is the 159th day of the year in the Gregorian calendar (160th in leap years), with 206 days remaining. ... 2005 (MMV) was a common year starting on Saturday of the Gregorian calendar. ... For the Manfred Mann album, see 2006 (album). ... May 9 is the 129th day of the year in the Gregorian calendar (130th in leap years). ... January 12 is the 12th day of the year in the Gregorian calendar. ... August 4 is the 216th day of the year in the Gregorian calendar (217th in leap years), with 149 days remaining. ... 2005 (MMV) was a common year starting on Saturday of the Gregorian calendar. ... For the Manfred Mann album, see 2006 (album). ... March 26 is the 85th day of the year in the Gregorian calendar (86th in leap years). ... January 6 is the 6th day of the year in the Gregorian calendar, with 359 days (360 in leap years) remaining. ... 2005 (MMV) was a common year starting on Saturday of the Gregorian calendar. ... The National Weather Service (NWS) is one of the six scientific agencies that make up the National Oceanic and Atmospheric Administration (NOAA) of the United States government. ... For the Manfred Mann album, see 2006 (album). ... August 6 is the 218th day of the year in the Gregorian calendar (219th in leap years), with 147 days remaining. ... The National Snow and Ice Data Center, or NSIDC, is a United States information and referral center in support of polar and cryospheric research. ... 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the Anno Domini (common) era. ... January 24 is the 24th day of the year in the Gregorian calendar. ... For the Manfred Mann album, see 2006 (album). ... April 25 is the 115th day of the year in the Gregorian calendar (116th in leap years). ... For the Manfred Mann album, see 2006 (album). ... October 6 is the 279th day of the year (280th in leap years). ... April 22 is the 112th day of the year in the Gregorian calendar (113th in leap years). ... 2003 (MMIII) was a common year starting on Wednesday of the Gregorian calendar. ... USA Today is a national American daily newspaper published by the Gannett Company. ... For the Manfred Mann album, see 2006 (album). ... September 15 is the 258th day of the year (259th in leap years). ... May 15 is the 135th day of the year in the Gregorian calendar (136th in leap years). ... 1999 (MCMXCIX) was a common year starting on Friday, and was designated the International Year of Older Persons by the United Nations. ... Science News is an American weekly magazine devoted to short articles about new scientific and technical developments, typically gleaned from recent scientific and technical journals. ... For the Manfred Mann album, see 2006 (album). ... September 15 is the 258th day of the year (259th in leap years). ... Portable Document Format (PDF), sometimes mistaken for Printable Document Format, is an open file format created by Adobe Systems in 1993 and is now being prepared for submission as an ISO standard. ... Monthly Weather Review is a publication of the American Meteorological Society. ... For the Manfred Mann album, see 2006 (album). ... September 15 is the 258th day of the year (259th in leap years). ... The NASA worm logo. ... For the Manfred Mann album, see 2006 (album). ... November 9 is the 313th day of the year (314th in leap years) in the Gregorian Calendar, with 52 days remaining. ... For the Manfred Mann album, see 2006 (album). ... November 10 is the 314th day of the year (315th in leap years) in the Gregorian Calendar, with 51 days remaining. ...

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