Hook echo

1999 Oklahoma tornado outbreak. It reached F5 strength on the Fujita scale.]
Kansas City, Missouri.] The hook echo is one of the classical hallmarks of tornado-producing supercell thunderstorms as seen on weather radar. The echo is produced by rain, hail, or even debris being wrapped around the supercell. The National Weather Service considers the presence of a hook echo as sufficient to justify issuing a tornado warning.

The hook echo has been recognized as a sign of tornado development for most of weather radar's existence. The first documented tracking of a hook echo was on April 9, 1953 by the Illinois State Water Survey, during preparations for an early test of radar's ability to measure rainfall rates.

Hook echoes are not always obvious. In the U.S. Southern states, thunderstorms tend to produce heavier rainfall which leads to the high precipitation (HP) variation supercell and obscures the hook shape. HP supercells will instead take on a kidney bean shape.

The use of doppler radar systems such as NEXRAD allows for detection of tornadoes even when the hook echo is not present, and for greater certainty when it is. By detecting the relative velocities of different parts of a storm, doppler radar can detect areas of rotation.

See also

* Bow echo
* Bounded weak echo region
* Tornado vortex signature
* Convective storm detection


* [http://chill.colostate.edu/w/CHILL_history The First Tornadic Hook Echo Weather Radar Observations]
* [http://www.srh.noaa.gov/meg/presentations/radar/sld026.html National Weather Service presentation on Radar Interpretation] - slide 26, detailing the difficulties of spotting hook echoes in the south
* [http://www.crh.noaa.gov/unr/?n=07-10-00 July 10th, 2000 Severe Weather (NWS)] - includes discussion of tornadic radar signatures
* [http://www.wdtb.noaa.gov/modules/twg02/TWG2002.pdf NWS - Tornado Warning Guidance: Spring 2002] (72kb PDF)
* [http://www.wdtb.noaa.gov/modules/sls00/M3RADAR.pdf NWS - Analysis of May 3, 1999 Oklahoma City Tornado Signature]

External links

* [http://amsglossary.allenpress.com/glossary/search?id=hook-echo1 Hook Echo] - AMS Glossary of Meteorology

Wikimedia Foundation. 2010.

Look at other dictionaries:

  • Écho en crochet — Formation et dissipation d un écho en crochet (échos au centre de l image) à Kansas City (Missouri) L’écho en crochet est une signature caractéristique dans la forme des échos de réflectivité de bas niveau d’un nuage de type cumulonimbus dans les …   Wikipédia en Français

  • Hook horror — context Infobox D D creature name=Hook horror alignment=Neutral type=Aberration subtype= source=Monster Manual II (3rd edition) first=White Dwarf #12In the Dungeons Dragons fantasy roleplaying game, a hook horror is a bipedal, subterranean… …   Wikipedia

  • Echo (Tom Petty album) — Infobox Album | Name = Echo Type = Album Artist = Tom Petty and the Heartbreakers Released = 13 April 1999 Recorded = 1998 Genre = Rock Length = 62:06 Label = Warner Bros. Producer = Rick Rubin, Tom Petty, Mike Campbell Reviews = *Allmusic… …   Wikipedia

  • Bow echo — A bow echo is a term describing the characteristic radar return from a mesoscale convective system that is shaped like an archer’s bow. These systems can produce severe straight line winds and occasionally tornadoes, causing major damage.… …   Wikipedia

  • Bounded weak echo region — Vertical cross section through a supercell showing the BWER. The bounded weak echo region, also known as a BWER or a vault, is a radar signature within a thunderstorm characterized by a local minimum in radar reflectivity at low levels which… …   Wikipedia

  • pendant echo — A radar signature generally similar to a hook echo, except that the hook shape is not as well defined. This is applicable to weather radar …   Aviation dictionary

  • Peter Hook — Peter « Hooky » Hook né le 13 février 1956 à Salford[1], dans le Lancastre (Angleterre), est un musicien anglais, bassiste du groupe cold wave Joy Division. Suite au suicide du chanteur Ian Curtis le 18 mai 1980 il… …   Wikipédia en Français

  • Rear flank downdraft — The rear flank downdraft or RFD is a region of dry air wrapping around the back of a mesocyclone in a supercell thunderstorm. These areas of descending air are thought to be essential in the production of many supercellular tornadoes. Large hail… …   Wikipedia

  • Convective storm detection — is the meteorological observation of deep, moist convection (DMC) and consists of detection, monitoring, and short term prediction. This term includes the minority of storms which do not produce lightning and thunder. Convective storms can… …   Wikipedia

  • Supercell — A supercell is a severe thunderstorm with a deep, continuously rotating updraft (a mesocyclone). [ [http://www.stormchasers.au.com/lemon7.htm 12B ] ] Of the four classifications of thunderstorms (supercell, single cell, multi cell, and squall… …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”

We are using cookies for the best presentation of our site. Continuing to use this site, you agree with this.