Tropical cyclones
Formation and naming
Development - Structure Naming - Seasonal lists - Full list
Effects
Effects Watches and warnings - Storm surge Notable storms - Retired hurricanes Image File history File links Size of this preview: 800 × 530 pixel Image in higher resolution (3032 × 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... Cyclone Catarina, a rare South Atlantic tropical cyclone viewed from the International Space Station on March 26, 2004 Hurricane and Typhoon redirect here. ... 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. ... Eye of Category 4 Hurricane Isabel seen from the International Space Station on September 15, 2003 The eye is a region of mostly calm weather found at the center of strong tropical cyclones. ... Presently, most tropical cyclones are given a name using one of several lists of tropical cyclone names. ... Due to their long-term persistence, and the need for a unique identifier in issuing forecasts and warnings, tropical cyclones are given names. ... This is a list of named tropical cyclones, giving all official names for tropical cyclones. ... Cyclone Catarina, a rare South Atlantic tropical cyclone viewed from the International Space Station on March 26, 2004 Hurricane and Typhoon redirect here. ... See Severe weather terminology for a comprehensive article on this term and related weather terms. ... ... This is a list of notable tropical cyclones, subdivided by basin and reason for notability. ... Tropical cyclones in the Atlantic or Eastern Pacific basins may have their names retired by the World Meteorological Organization for various reasons, such as damage or fatalities. ...
Climatology and tracking
Basins - RSMCs - TCWCs - Scales Observation - Rainfall forecasting - Rainfall climatology Traditionally, areas of tropical cyclone formation are divided into seven basins. ... These centres are responsible for the distribution of information, advisories, and warnings regarding the specific program they have a part of, agreed by consensus at the World Meteorological Organization as part of the World Weather Watch. ... These five regional warning centers are part of the World Meteorological Organization tropical cyclone programme, and act to observe, name, and forecast tropical cyclones in their respective sections of the world, supplementing the work of the main Regional Specialized Meteorological Centres. ... NASA QuikSCAT image of Typhoon Nesat (2005) showing the near-surface winds generated by the storm 10 meters above the ocean. ... Surface weather map of the Labor Day Hurricane of 1935 moving up the west coast of Florida Tropical cyclone obervation has been carried out over the past couple of centuries in various ways: the passage of typhoons, hurricanes, as well as other tropical cyclones have been detected by word of... A map of all tropical cyclone tracks, encompassing the period between the years 1985 and 2005. ...

While flooding is common to tropical cyclones near a landmass, there are a few factors which lead to excessive rainfall from tropical cyclones. Slow motion, as was seen during Hurricane Danny (1997) and Hurricane Wilma, can lead to high amounts. The presence of topography near the coast, as is the case across much of Mexico, Haiti, the Dominican Republic, much of Central America, Madagascar, Réunion, China, and Japan acts to magnify amounts due to upslope flow into the mountains. Strong upper level forcing from a trough moving through the Westerlies, as was the case during Hurricane Floyd, can lead to high amounts even from systems moving at an average forward motion. A combination of two of these factors could be especially crippling, as was seen during Hurricane Mitch in Central America.^[1] Picture of flooding in Amphoe Sena, Ayutthaya Province, Thailand For other uses, see Flood (disambiguation). ... A B C D 5 E F G Categories: | | | | | ... Lowest pressure 882 mbar (hPa) (Lowest pressure ever recorded in an Atlantic hurricane) Damage $28. ... Map of Central America Central America is the central geographic region of the Americas. ... Lowest pressure 921 mbar (hPa)[1] Damages $4. ... Lowest pressure 905 mbar (hPa) Damage $5+ billion (1998 USD) $6 billion (2006 USD) Fatalities 11,000–18,000 direct (deadliest Atlantic hurricane since 1780 hurricane) Areas affected Central America (particularly Honduras and Nicaragua), Yucatán Peninsula, South Florida Part of the 1998 Atlantic hurricane season Hurricane Mitch was one... Map of Central America Central America is the central geographic region of the Americas. ...

One of the most significant threats from tropical cyclones is heavy rainfall. Between 1970-2004, inland flooding from tropical cyclones caused a majority of the fatalities from tropical cyclones in the United States.^[2] This statistic changed in 2005, when Hurricane Katrina's impact alone shifted the most deadly aspect of tropical cyclones back to storm surge, which has historically been the most deadly aspect of strong tropical cyclones.^[3] During the 2005 season, flooding related to Hurricane Stan's broad circulation lead to 1662-2000 deaths.^[4] Cyclone Catarina, a rare South Atlantic tropical cyclone viewed from the International Space Station on March 26, 2004 Hurricane and Typhoon redirect here. ... Lowest pressure 902 mbar (hPa; 26. ... ... Lowest pressure 977 mbar (hPa; 28. ...

Rainfall distribution around a tropical cyclone

General distribution

Isaac Cline underwent the first investigations into rainfall distribution around tropical cyclones in the early 1900s. He found that a larger proportion of rainfall typically falls in advance of the center (or eye) than after the center's passage, with the highest percentage falling in the right-front quadrant. Father Viñes of Cuba found that some tropical cyclones can have their highest rainfall rates in the right rear quadrant within a training (non-moving) inflow band (Tannehill 1942). Rainfall is found to be strongest in their inner core, within a degree of latitude of the center, with lesser amounts farther away from the center (Riehl 1954). Most of the rainfall in hurricanes is concentrated within its radius of gale-force winds.^[5] The chart to the right was developed by Riehl in 1954 using meteorological equations which assume a gale radius of about 210 statute miles/300 km, a fairly symmetric cyclone, and does not consider the effect hills and mountains would have on the rainfall distribution, or vertical wind shear. As seen in the statistics from China, local amounts can exceed this chart by a factor of two due to topography. Wind shear tends to lessen the amounts below what is shown on the table. A mile is any of several units of distance, or, in physics terminology, of length. ... km redirects here. ... An inch (plural: inches; symbol or abbreviation: in or, sometimes, ″ - a double prime) is the name of a unit of length in a number of different systems, including English units, Imperial units, and United States customary units. ... A millimetre (American spelling: millimeter, symbol mm) is an SI unit of length that is equal to one thousandth of a metre. ... Isaac Cline Isaac Monroe Cline (October 13, 1861 – August 3, 1955 was the chief meteorologist at the Galveston, Texas office of the US Weather Bureau from 1889 to 1901. ... Rain is a source of precipitation which forms when separate drops of water fall to the Earths surface from clouds. ... // First flight by the Wright brothers, December 17, 1903. ... A human eye. ... Fig. ... Ivan Ray Tannehill was born in 1890 and died in 1959. ... Latitude, usually denoted symbolically by the Greek letter phi, , gives the location of a place on Earth north or south of the equator. ... ... 1954 (MCMLIV) was a common year starting on Friday of the Gregorian calendar. ... Wind shear is a difference in wind speed or direction between two points in the atmosphere. ...

Storm size

The relative sizes of Typhoon Tip, Cyclone Tracy, and the United States.

Larger tropical cyclones have larger rain shields, which can lead to higher rainfall amounts farther from the cyclone's center.^[5] This is generally due to the longer time frame rainfall falls at any one spot in a larger system, as long as forward motion is similar to that of a smaller system. Some of the difference seen concerning rainfall between larger and small storms could be the increased sampling of rainfall within a larger tropical cyclone when compared to that of a compact cyclone; in other words, the difference could be the result of a statistical problem. Illustrating the extremes in tropical cyclone sizes. ... Lowest pressure 870 hPa (mbar) (record) Damages Unknown Fatalities 68 direct Areas affected Japan Part of the 1979 Pacific typhoon season This article deals with the 1979 Typhoon Tip. ... Lowest pressure 950 hPa (mbar)[1] Damage $4 billion (1998 AUD)[2] $2. ...

Slow/looping motion on rainfall magnitude

Storms which have moved slowly, or loop, over a succession of days lead to the highest rainfall amounts for several countries. Riehl calculated that 33.97 inches/863 mm of rainfall per day can be expected within one-half degree, or 35 miles/56 km, of the center of a mature tropical cyclone. Many tropical cyclones progress at a forward motion of 10 knots, which would limit the duration of this excessive rainfall to around one-quarter of a day, which would yield about 8.50 inches/216 mm of rainfall. This would be true over water, within 100 miles/160 km of the coastline,^[6] and outside topographic features. As a cyclone moves farther inland and is cut off from its supply of warmth and moisture (the ocean), rainfall amounts from tropical cyclones and their remains decrease quickly.^[7]

Vertical wind shear

Vertical wind shear forces the rainfall pattern around a tropical cyclone to become highly asymmetric, with most of the precipitation falling downwind of the shear, or downshear. In other words, southwesterly shear forces the bulk of the rainfall northeast of the center. If the wind shear is strong enough, the bulk of the rainfall will move away from the center leading to what is known as an exposed circulation center. When this occurs, the potential magnitude of rainfall with the tropical cyclone will be significantly reduced. Wind shear is a difference in wind speed or direction between two points in the atmosphere. ...

Interaction with frontal boundaries/upper level troughs

As a tropical cyclone interacts with an upper-level trough and the related surface front, a distinct northern area of precipitation is seen along the front ahead of the axis of the upper level trough. This type of interaction can lead to the appearance of the heaviest rainfall falling along and to the left of the tropical cyclone track, with the precipitation streaking hundreds of miles or kilometers downwind from the tropical cyclone.^[8] Cyclone Catarina, a rare South Atlantic tropical cyclone viewed from the International Space Station on March 26, 2004 Hurricane and Typhoon redirect here. ... A trough is an elongated region of relatively low atmospheric pressure, often associated with fronts. ... ethan has a z-400 and its freekin sweet and he can ride a wheelie for blocks and Donny T has a go cart that has no brakes A surface weather analysis for the United States on October 21, 2006. ...

Tools used to forecast tropical cyclone rainfall

r-CLIPER for Isabel (2003)

Climatology and persistence

The Hurricane Research Division of the Atlantic Oceanographic and Meteorological Laboratory created the r-CLIPER (rainfall climatology and persistence) model to act as a baseline for all verification regarding tropical cyclone rainfall. The theory is, if the global forecast models cannot beat predictions based on climatology, than there is no skill in their use. There is a definite advantage to using the forecast track with r-CLIPER because it could be run out 120 hours/five days with no problems.^[9] The short range variation which uses persistence is the TRaP technique, which uses satellite-derived rainfall amounts from microwave imaging satellites and extrapolates the current rainfall configuration forward for 24 hours along the current forecast track. This technique's main flaw is that it assumes a steady state tropical cyclone which undergoes little structural change with time, which is why it is only run forward for 24 hours into the future.^[10] The Atlantic Oceanographic and Meteorological Laboratory (AOML) is a laboratory in National Oceanic and Atmospheric Administrations Office of Oceanic and Atmospheric Research (OAR). ... Rain is a source of precipitation which forms when separate drops of water fall to the Earths surface from clouds. ... Climatology is the study of climate, scientifically defined as weather conditions averaged over a period of time,[1] and is a branch of the atmospheric sciences. ... Cyclone Catarina, a rare South Atlantic tropical cyclone viewed from the International Space Station on March 26, 2004 Hurricane and Typhoon redirect here. ... Microwaves are electromagnetic waves with wavelengths longer than those of terahertz (THz) frequencies, but relatively short for radio waves. ... Satellite imagery consists of photographs of Earth or other planets made from artificial satellites. ... For alternative meanings see steady state (disambiguation). ...

GFS for Isabel (2003)

Numerical weather prediction

Further information: Tropical cyclone prediction model

Computer models can be used to diagnose the magnitude of tropical cyclone rainfall. Since forecast models output their information on a grid, they only give a general idea as to the areal coverage of moderate to heavy rainfall. No current forecast models run at a small enough grid scale (1 km or smaller) to able to detect the absolute maxima measured within tropical cyclones. Of the United States forecasting models, the best performing model for tropical cyclone rainfall forecasting is known as the GFS, or Global Forecasting System.^[11] The GFDL model has been shown to have a high bias concerning the magnitude of heavier core rains within tropical cyclones.^[12] Hurricane Epsilon defied and frustrated forecasters by persisting in a hostile environment for a remarkably long time A tropical cyclone prediction model is a computer program that uses meteorological data to predict the motion and intensity of tropical cyclones. ... The Geophysical Fluid Dynamics Laboratory (GFDL) is a laboratory in the National Oceanic and Atmospheric Administration (NOAA)/Office of Oceanic and Atmospheric Research (OAR). ...

Kraft rule of thumb

In the 1960's, this rule of thumb came into being. It was noted from rainfall amounts (in imperial units) reported by the first order rainfall network in the United States that the storm total rainfall fit a simple equation: 100 divided by the speed of motion in knots.^[8] This rule works as long as a tropical cyclone is moving and only the first order or synoptic station network (with observations spaced about 60 miles/100 km apart) are used to derive storm totals. The main problem with this rule is that the rainfall observing network is denser than either the synoptic reporting network or the first order station networks, which means the absolute maximum is likely to be missed. Another problem is that it does not take the size of the tropical cyclone or topography into account. A rule of thumb is an easily learned and easily applied procedure for approximately calculating or recalling some value, or for making some determination. ...

The 8 inch/203 mm rule of thumb

Rusty Pfost, now the head of the Miami National Weather Service Forecast Office, did a study in 1999 reviewing rainfall totals from tropical systems affecting Florida between 1960 and 1998. He found that for tropical cyclones moving at greater than 6 knots, the average storm total was normally in the 5–10 inch (127–254 mm) range. Slower moving storms usually forced greater than 15 inches (381 mm) of rain to fall.^[8] 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. ...

The 16 inch/406 mm rule of thumb

U.S. Tropical Cyclone Rainfall Accumulations per time frame

David Roth, a forecaster at the Hydrometeorological Prediction Center, determined that the average amount for all tropical cyclones impacting the United States was 13.34 inches (339 mm) between 1991 and 2005.^[13] When removing the storms that grazed the domain, an average of near 16 inches/406 mm was obtained. Using this latter amount appears to work best for systems that experience little vertical wind shear and are of at least average size. Amounts measured in small/midget tropical cyclones showed storm total amounts closer to 6 inches/152 mm. Operationally, variations to these amounts are introduced if the cyclone encounters topography or a nearby frontal zone, sea surface temperatures underneath the tropical cyclone are anticipated to drop below 26 Celsius prior to landfall, or the storm is significantly sheared. Image File history File links ShortTermRainfallAccumulations. ... Image File history File links ShortTermRainfallAccumulations. ... Cyclone Catarina, a rare South Atlantic tropical cyclone viewed from the International Space Station on March 26, 2004 Hurricane and Typhoon redirect here. ... The Hydrometeorological Prediction Center is one of several Service Centers under the umbrella of the National Centers for Environmental Prediction (NCEP), operating under the control of the National Weather Service, which in turn is part of the National Oceanic and Atmospheric Administration (NOAA) of the U.S. government. ... 1991 (MCMXCI) was a common year starting on Tuesday of the Gregorian calendar. ... 2005 (MMV) was a common year starting on Saturday of the Gregorian calendar. ... Wind shear is a difference in wind speed or direction between two points in the atmosphere. ...

See also

• Rule of thumb
• Tropical cyclones
• Tropical cyclone rainfall climatology
• Tropical cyclone observation

A rule of thumb is an easily learned and easily applied procedure for approximately calculating or recalling some value, or for making some determination. ... This article is about weather phenomena. ... A map of all tropical cyclone tracks, encompassing the period between the years 1985 and 2005. ... Surface weather map of the Labor Day Hurricane of 1935 moving up the west coast of Florida Tropical cyclone obervation has been carried out over the past couple of centuries in various ways: the passage of typhoons, hurricanes, as well as other tropical cyclones have been detected by word of...

References

Printed media

1. Ivan Ray Tannehill. Hurricanes. Princeton University Press: Princeton, 1942.
2. Herbert Riehl. Tropical Meteorology. McGraw-Hill Book Company, Inc.: New York, 1954.

World Wide Web