Meteorology Commons^™

Incorporating Uh Occurrence Time To Ensemble-Derived Tornado Probabilities, Burkely T. Gallo, Adam J. Clark, Bryan T. Smith, Richard L. Thompson, Israel Jirak, Scott R. Dembek

United States Department of Commerce: Staff Publications

Probabilistic ensemble-derived tornado forecasts generated from convection-allowing models often use hourly maximum updraft helicity (UH) alone or in combination with environmental parameters as a proxy for right-moving (RM) supercells. However, when UH occurrence is a condition for tornado probability generation, false alarm areas can occur from UH swaths associated with nocturnal mesoscale convective systems, which climatologically produce fewer tornadoes than RM supercells. This study incorporates UH timing information with the forecast near-storm significant tornado parameter (STP) to calibrate the forecast tornado probability. To generate the probabilistic forecasts, three sets of observed climatological tornado frequencies given an RM supercell and STP …

The Impact Of Past Experience With Tornadoes On Future Decisions, Emily Paltz, Michael Hayes

Honors Theses

Tornadoes are a dangerous threat to public safety. The National Weather Service (NWS), therefore, advises the public to go to an interior room on the lowest level of their houses when a tornado warning is issued for their area. As the NWS Central Region Service Assessment of the Joplin, Missouri Tornado published in July 2011 reveals, however, this is often not the first action taken after learning that there is danger of being hit by a tornado. Rather, people need to seek confirmation from more than one source before following the recommended action. The goal of this research project is …

Impact Of Past Experiences With Tornadoes On Future Decisions In Nebraska, Emily Paltz, Michael Hayes, Matthew Van Den Broeke

UCARE Research Products

The National Weather Service (NWS) advises the public to go to an interior room on the lowest level of their houses when a tornado warning is issued for their area. As the NWS Central Region Service Assessment of the Joplin, Missouri Tornado published in July 2011 reveals, however, this is often not the first action taken after learning that there is danger of being hit by a tornado. Rather, people need to seek confirmation from more than one source before following the recommended action. The goal of this research project is to determine how the number of sources and what …

A Recommendation For An Enhanced Fujita Scale (Ef-Scale)

United States Department of Commerce: Staff Publications

Background

National Weather Service (NWS) personnel who are responsible for rating tornadoes have expressed frustrations in applying the Fujita Scale in a consistent and accurate manner. Weak links in a structural system or a slow-moving storm sometimes lead to an overrating of a tornado event. Several technical articles suggest that wind speeds associated with some descriptions of damage are too high. For example, a 260 mph wind speed is not required to completely destroy a well constructed house and blow away the debris. The damage occurs at significantly lower wind speeds. Minor et al. (1977) and Phan and Simiu (2003) …

Thunderstorms And Tornadoes Of February 1, 1955, Jean T. Lee

NOAA Technical Reports and Related Materials

The purpose of this paper is to describe and illustrate some of the features that are of particular interest in the forecasting of one of the most death-dealing series of convective storms of the 1950s that occurred during the afternoon and evening of February 1, 1955. This series of severe storms included tornadoes, destructive winds, hail, and heavy rain that first struck near Marianata, Arkansas, then roared through Commerce Landing, Mississippi and northern Mississippi. then moved on to near Huntsville, Alabama.

Includes features at the surface, at 850 mb, 700 mb, and 500 mb, and upper air conditions, along with …