A tornado warning is a public warning that is issued by weather forecasting agencies to an area in the direct path of a tornado, or a severe thunderstorm capable of producing one, and advises individuals in that area to take cover. Modern weather surveillance technology such as Doppler weather radar can detect rotation in a thunderstorm, allowing for early warning before a tornado develops. They are also commonly issued based on reported visual sighting of a tornado, funnel cloud, or wall cloud, typically from weather spotters or the public, but also law enforcement or local emergency management. When radar is unavailable or insufficient, such ground truth is crucial. In particular, a tornado can develop in a gap of radar coverage, of which there are several known in the United States.
A tornado watch is a statement issued by weather forecasting agencies to advise the public that atmospheric conditions in a given region may lead to the development of tornadoes within the region over a period of several hours. In addition to the potential for tornado development, thunderstorms that develop within the watch area may contain large hail, straight-line winds, intense rainfall and/or flooding that pose a similar damage risk as the attendant tornado threat.
A severe thunderstorm watch is a statement issued by weather forecasting agencies to advise the public that atmospheric conditions in a given region may lead to the development of severe thunderstorms within the region over a period of several hours. The criteria for issuing a watch varies by country, and may also include torrential rainfall and tornadoes. A watch may also be issued several hours ahead of the arrival of a mature and organized complex of storms, or more clustered or discrete storm activity.
A severe thunderstorm warning is a type of public warning for severe weather that is issued by weather forecasting agencies worldwide when one or more severe thunderstorms have been detected by Doppler weather radar, observed by weather spotters, or reported by an emergency management agency, law enforcement, or the general public. Unlike a watch, a warning is issued to areas in the direct path of active severe thunderstorms, that are expecting a direct impact typically within an hour. Severe thunderstorms can cause property damage and injury due to large hail, high winds, and flooding due to torrential rainfall. The exact criteria to issue a warning varies from country to country.
The National Weather Service (NWS) is an agency of the United States federal government that is tasked with providing weather forecasts, warnings of hazardous weather, and other weather-related products to organizations and the public for the purposes of protection, safety, and general information. It is a part of the National Oceanic and Atmospheric Administration (NOAA) branch of the Department of Commerce, and is headquartered in Silver Spring, Maryland, within the Washington metropolitan area. The agency was known as the United States Weather Bureau from 1890 until it adopted its current name in 1970.
The Storm Prediction Center (SPC) is a US government agency that is part of the National Centers for Environmental Prediction (NCEP), operating under the control of the National Weather Service (NWS), which in turn is part of the National Oceanic and Atmospheric Administration (NOAA) of the United States Department of Commerce (DoC).
This article describes severe weather terminology used by the National Weather Service (NWS) in the United States. The NWS is a government agency operating as an arm of the National Oceanic and Atmospheric Administration (NOAA) branch. It defines precise meanings for nearly all of its weather terms.
The tornado outbreak of January 1–2, 2006, was one of the largest tornado outbreaks ever recorded in the month of January. The outbreak affected much of the Central and Southern United States and produced 20 tornadoes. The tornadoes caused considerable damage in the states of Kentucky and Georgia. There were no tornado related fatalities and only minor injuries were reported.
In weather forecasting in the United States, "particularly dangerous situation" (PDS) is enhanced wording used by the National Weather Service to convey special urgency in some watch or warning messages for unusually extreme and life-threatening severe weather events, above and beyond the average severity for the type of event. It is used in the format "This is a particularly dangerous situation..." at the discretion of the issuing forecaster. A watch or warning bearing the phrase is referred to as a PDS watch or PDS warning as shorthand jargon.
The Corn Belt derecho was a progressive derecho which affected a large area of the central United States on June 29, 1998. In the morning, thunderstorms, including a supercell, developed over South Dakota and tracked into central Iowa. As the thunderstorms reached central Iowa, a strong rear-inflow jet developed which caused the thunderstorm to take on a different characteristic, becoming a derecho. It traveled more than 600 miles in about ten hours, causing more than $125 million worth of widespread damage destruction, especially to crops, and was responsible for power outages to nearly a half a million people.
National Weather Service Lincoln, Illinois also known as National Weather Service Central Illinois is a weather forecast office responsible for monitoring weather conditions for 35 counties in Central and Southeastern Illinois. The Central Illinois office initially consisted of two forecast offices in Peoria and Springfield until the current location in Lincoln became the sole local forecast office in 1995. Federal meteorology offices and stations in the region date back to the 19th century when the Army Signal Service began taking weather observations using weather equipment at the Springer Building in Springfield. Since that time the presence of the National Weather Service greatly increased with the installation of new weather radars, stations and forecast offices. The current office in Lincoln maintains a WSR-88D (NEXRAD) radar system, and Advanced Weather Interactive Processing System (AWIPS) that greatly improve forecasting in the region. Lincoln is in charge of weather forecasts, warnings and local statements as well as aviation weather.
National Weather Service Chicago, currently based in Romeoville, Illinois, is a weather forecast office responsible for monitoring weather conditions for 23 counties in Northern Illinois, the Chicago metropolitan area and Northwest Indiana. The Army Signal Service established the first federal weather office in the region in Chicago on October 15, 1870. During May 1894 the Chicago Weather Bureau was given a new forecast area extending from the Great Lakes region all the way to the Rocky Mountains. The current National Weather Service Chicago is located in Romeoville and is in charge of issuing local forecasts and weather warnings for the Chicago area. It is one of only two National Weather Service offices in Illinois, the other being National Weather Service Central Illinois in Lincoln, Illinois. The National Weather Service Chicago forecast office is located adjacent to the Lewis University Airport in Romeoville, Illinois.
National Weather Service - Shreveport, LA (SHV) is one of 122 weather forecast offices around the United States. It is responsible for issuing public and aviation forecasts and warning for South Central and Southwestern Arkansas, Southeastern Oklahoma, and Eastern and Northeastern Texas Counties, as well as for North Central and Northwestern Louisiana Parishes. It is co-located with a weather radar (KSHV) of the NEXRAD network and an upper air sounding facility. It controls the issuance of weather information and bulletins on a certain number of NOAA Weather Radio.
The December 17–22, 2012 North American blizzard was a winter storm that affected the Midwestern and Eastern United States. Forming on December 17, the winter storm moved across the midwest, forcing schools to close throughout the region. Numerous warnings and advisories had been posted by the National Weather Service for many states, including Iowa, Nebraska, Illinois, and Wisconsin. Both O'Hare International Airport and Midway International Airport in Chicago, Illinois canceled most departures and arrivals. According to flight tracking website FlightStats.com, more than 1,000 flights were canceled across the region. More than 130,000 customers were without power across the west and midwest.
National Weather Service - Norman, Oklahoma is a Weather Forecast Office (WFO) of the National Weather Service based in Norman, Oklahoma, which is responsible for forecasts and the dissemination of weather warnings and advisories for central and most of western Oklahoma, and western portions of north Texas. It is located in the National Weather Center on the University of Oklahoma campus, where it acts as one of the NOAA Weather Partners, a group of close-together weather-related agencies of the National Oceanic and Atmospheric Administration. NWS Norman is currently overseen by Mark Fox, who serves as the Meteorologist In Charge of the office.
National Weather Service - Pleasant Hill/Kansas City, Missouri is a Weather Forecast Office (WFO) of the National Weather Service, which is responsible for forecasts and the dissemination of weather warnings and advisories for 37 counties in northern and western Missouri and seven counties in extreme eastern Kansas, including the Kansas City and St. Joseph metropolitan areas. Though, as the Storm Prediction Center (SPC) in Norman, Oklahoma is responsible for issuing severe thunderstorm and tornado watches, the Pleasant Hill/Kansas City WFO only composes outline and status updates for SPC-issued watches affecting any portion of its designated County Warning Area.
The National Weather Service Fort Worth, Texas is a local weather forecast office of the National Weather Service responsible for monitoring weather conditions for 46 counties in north central Texas, including the Dallas-Fort Worth Metro Area and Waco, Texas.
The August 2020 Midwest derecho was a powerful derecho affecting the Midwestern United States on August 10–11, 2020, primarily eastern Nebraska, Iowa, Illinois, Wisconsin, and Indiana. It caused high winds and spawned an outbreak of weak tornadoes. Some areas reported torrential rain and large hail.
Starting on the evening of July 13 and extending through July 16, 2024, an intense sequence of severe weather outbreaks affected much of the Midwestern and Northeastern United States. This included two significant derechoes that each had wind gusts exceeding 100 mph (160 km/h), as well as multiple tornado outbreaks that produced a combined 90 tornadoes across the affected areas. A ring of fire pattern fueled multiple systems that brought heavy rain and a tornado outbreak to northern Illinois, contributing to a partial dam failure in Washington County, Illinois, and multiple events of 90 mph (140 km/h) wind gusts. The sequence as a whole killed five people and injured three more.
