Severe thunderstorm with a clear slot near main updraft core. Typically a tornado, if present, will form in this area.

A severe thunderstorm warning is issued when trained Skywarn spotters or doppler radar indicate a strong thunderstorm is producing dangerously large hail or high winds, capable of causing significant damage. It does not account for lightning or flooding. A warning must not be confused with a severe thunderstorm watch. Image File history File links Size of this preview: 800 × 520 pixelsFull resolution (1828 × 1188 pixel, file size: 1. ... Image File history File links Size of this preview: 800 × 520 pixelsFull resolution (1828 × 1188 pixel, file size: 1. ... A severe thunderstorm is a thunderstorm with winds 58 mph or greater, 3/4 inch or larger hail, or tornadoes. ... A tornado in central Oklahoma. ... SKYWARN is a program of the United States National Weather Service (NWS). ... Doppler Effect Doppler radar uses the Doppler effect to measure the radial velocity of targets in the antennas directional beam. ... This article needs additional references or sources for verification. ... Flooding in Amphoe Sena, Ayutthaya Province, Thailand. ... Thunderstorm out flow from storm core shows up as sheets of wind driven rain spreading from right to left in 1982 photo. ...

In the U.S., the National Weather Service defines a severe thunderstorm as having large hail being at least ¾ inch (19 mm) in diameter, high winds as being 58 miles per hour (93 km/h) or greater, producing tornadoes, or any combination of the three. But in the US State of Kansas, where severe storms are very common, NWS offices covering the state of Kansas define a Severe Thunderstorm as having large hail the size or 1 Inch or larger, winds in excess of 60MPH, producing tornadoes, or any combination of the three. Motto: (Out Of Many, One) (traditional) In God We Trust (1956 to date) Anthem: The Star-Spangled Banner Capital Washington D.C. Largest city New York City None at federal level (English de facto) Government Federal constitutional republic  - President George Walker Bush (R)  - Vice President Dick Cheney (R) Independence from... 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. ... A millimetre (American spelling: millimeter), symbol mm is an SI unit of length that is equal to one thousandth of a metre. ... Kilometre per hour (American spelling: kilometer per hour) is a unit of both speed (scalar) and velocity (vector). ... For other uses of Tornado, see Tornado (disambiguation). ... This article needs additional references or sources for verification. ...

In Canada, a severe thunderstorm has one or more of the following:

• wind gusts of >90 km/h
• hail with a diameter of >20 mm
• rainfall of >50 mm in an hour or >75 mm in three hours
• tornadoes

A severe thunderstorm warning means there is significant danger for the warned area. Occasionally, severe thunderstorms can and do produce a tornado without warning. However, frequently a severe thunderstorm will produce serious wind damage as severe as a tornado. A severe thunderstorm warning can also be upgraded to a tornado warning if a tornado is detected on radar or actually spotted. Generally, but not always, a severe thunderstorm watch or tornado watch will precede a warning. A tornado in central Oklahoma. ... Tornado at beginning of life. ... Thunderstorm out flow from storm core shows up as sheets of wind driven rain spreading from right to left in 1982 photo. ... A tornado watch is issued when weather conditions are favorable for the development of severe thunderstorms that are capable of producing tornados. ...

Some storms, especially in the Great Plains, may produce massive hailstones the size of baseballs or even grapefruits, falling fast enough to kill a person by repeated blunt trauma. Everyone in the path of such a storm should take cover immediately, as it is very dangerous and possibly life-threatening. The Great Plains covers much of the central United States, portions of Canada and Mexico. ... Binomial name Macfad. ... In medical terminology, blunt trauma, blunt injury, non-penetrating trauma or blunt force trauma refers to a type of physical trauma caused to a bodypart, either by impact, injury or physical attack; the latter usually being referred to as blunt force trauma. ...

In the United States, the National Weather Service issues warnings for tornadoes and severe thunderstorms in polygon shapes. Warnings are usually deliniated by county or by a section of a county. 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. ... Look up polygon in Wiktionary, the free dictionary. ...

A similar warning is issued by Environment Canada's Meteorological Service of Canada from their offices in Vancouver, Edmonton, Toronto, Montreal and Dartmouth. Environment Canada is the department of the government of Canada with responsibility for coordinating environmental policies and programs as well as preserving and enhancing the natural environment and conservation of wildlife. ... The Meteorological Service of Canada (MSC) is a Canadian government agency which provides meteorological information. ... Motto: By Sea, Land, and Air We Prosper Location of Vancouver within the Greater Vancouver Regional District in British Columbia, Canada Coordinates: , Country  Canada Province  British Columbia Region Lower Mainland Regional District Greater Vancouver Incorporated 1886 Government  - Mayor Sam Sullivan (NPA)  - City Council List of Councilors Suzanne Anton (NPA) Peter... Nickname: Motto: Industry - Integrity - Progress Location of Edmonton within census division number 11, Alberta, Canada. ... Nickname: Motto: Concordia Salus (well-being through harmony) Coordinates: , Country Canada Province Quebec Founded 1642 Established 1832 Government  - Mayor Gérald Tremblay Area [1][2][3]  - City 365. ... Ferry running between Halifax and Dartmouth, docked at Dartmouth Ferry Terminal. ...

Example of a Severe Thunderstorm Warning

 SEVERE THUNDERSTORM WARNING WYC029-039-042315- /O.NEW.KRIW.SV.W.0039.070804T2213Z-070804T2315Z/ BULLETIN - EAS ACTIVATION REQUESTED SEVERE THUNDERSTORM WARNING NATIONAL WEATHER SERVICE RIVERTON WY 413 PM MDT SAT AUG 4 2007 THE NATIONAL WEATHER SERVICE IN RIVERTON HAS ISSUED A * SEVERE THUNDERSTORM WARNING FOR... CENTRAL PARK COUNTY IN NORTHWEST WYOMING... NORTHERN TETON COUNTY IN NORTHWEST WYOMING... * UNTIL 515 PM MDT * AT 406 PM MDT...TRAINED WEATHER SPOTTERS REPORTED A LINE OF SEVERE THUNDERSTORMS CAPABLE OF PRODUCING DAMAGING WINDS IN EXCESS OF 60 MPH. THESE STORMS WERE LOCATED ALONG A LINE EXTENDING FROM 7 MILES NORTH OF FLOATING ISLAND LAKE TO MUD VOLCANO TO 9 MILES WEST OF SOUTH ENTRANCE...OR ALONG A LINE EXTENDING FROM 41 MILES NORTHEAST OF WEST YELLOWSTONE TO 32 MILES EAST OF WEST YELLOWSTONE TO 22 MILES NORTHEAST OF JUDKINS...AND MOVING EAST AT 20 MPH. * SEVERE THUNDERSTORMS WILL BE NEAR... SOUTH ENTRANCE BY 420 PM MDT... LEWIS FALLS...LEWIS LAKE AND GRANT VILLAGE BY 425 PM MDT... RIDDLE LAKE AND LAKE BY 430 PM MDT... LAMAR VALLEY BY 440 PM MDT... ICE BOX CANYON AND HEART LAKE BY 450 PM MDT... NORTHEAST ENTRANCE BY 500 PM MDT... DAMAGING WINDS CAN BE EXPECTED WITH THIS STORM. TAKE COVER NOW IN A STURDY BUILDING AND AVOID WINDOWS. DAMAGING WINDS UP TO 55 MPH WERE REPORTED IN WESTERN YELLOWSTONE PARK WITH THIS STORM. THIS IS A DANGEROUS STORM...SEEK SAFE SHELTER AND STAY AWAY FROM WINDOWS! THIS WARNING REPLACES THE PREVIOUS WARNING WHICH INCLUDED YELLOWSTONE NATIONAL PARK. REPORT SEVERE WEATHER TO THE NATIONAL WEATHER SERVICE OFFICE IN RIVERTON AT 1-800-211-1448. LAT...LON 4512 11054 4465 11053 4406 11096 4429 10998 4486 10978 4533 10978 $$ BRANHAM 

External link

Meteorological Service of Canada

United States National Weather Service