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  • Author or Editor: Charles A. Doswell III x
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Barry E. Schwartz and Charles A. Doswell III

Meteorologists, like most scientists, often use observational data assuming the necessary steps have been taken to ensure that the quality of the data has been properly controlled. Experience developing an archive of upper-air observations from historical and real-time data suggests that some of the steps necessary to assure the basic scientific integrity of these data have not, in fact, been taken. This is especially so in recent years, since the introduction of automation into data observing and processing. Some of the problems and issues related to the observation, collection, and archiving of upper-air data are discussed. The intent of this paper is to stimulate dialogue within the upper-air-data–user community about these issues so that appropriate action can be formulated and implemented.

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Frederick Sanders and Charles A. Doswell III

Detailed analysis of the temperature and moisture fields based on routine hourly surface observations in North America can provide a rational basis for surface feature analysis, thus clarifying the present confusion. Recognition of surface features is an important part of weather forecasting and is especially needed in a careful diagnosis for the prospects of deep convection.

Surface temperature gradients are advocated as the primary basis for identifying fronts; examples are given of gross discrepancies in current operational practice between the surface temperature fields and the associated frontal analyses. Surface potential temperature, selected as a means of compensating for elevation differences, is analyzed in the western United States for a period in which a strong, damaging cold front develops and dissipates over a period of less than 24 h. Frontogenesis-related calculations, based on detailed surface temperature analyses, help to explain a case of focusing of heavy precipitation in northern Kentucky that produced a flash flood.

Conditions for the initiation of intense convection are illustrated by detailed analyses of the surface moisture and temperature fields. These are used to estimate the buoyancy of surface air lifted to midtroposphere and show the relationship of this buoyancy to ensuing convection. The analyses aid in recognition of the surface dryline (a feature commonly misanalyzed as a cold front) and those convectively produced pools of cold air at the surface that often play a major role in the subsequent redevelopment of convection.

The proposed analyses might be difficult to achieve manually in operational practice during busy weather situations, but this could be facilitated by using objective methods with present and prospective workstations. Once surface features are identified, their temporal and spatial evolution must be followed carefully since they can change rapidly.

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Charles A. Doswell III, Leslie R. Lemon, and Robert A. Maddox

Several key events in the history of modern meteorology are reviewed and analyzed in light of the current state of forecasting. A common thread in much of the material reviewed is the need for greater interaction between research meteorologists and forecasters. Greatly hindering this desirable goal is the inadequate training system for forecast meteorologists. Some possible means for altering the structures within which forecaster training takes place are examined. Responses and commitment to improve the current situation are solicited.

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David M. Schultz, Yvette P. Richardson, Paul M. Markowski, and Charles A. Doswell III

After tornado outbreaks or individual violent tornadoes occur in the central United States, media stories often attribute the location, number, or intensity of tornadoes to the “clash of air masses” between warm tropical air and cold polar air. This article argues that such a characterization of tornadogenesis is oversimplified, outdated, and incorrect. Airmass boundaries and associated temperature gradients can be important in tornadogenesis, but not in the ways envisioned on the synoptic scale with the clash-of-air-masses conceptual model. In fact, excessively strong horizontal temperature gradients (either on the synoptic scale or associated with a storm's own cool outflow) may be detrimental to tornadogenesis. Where adjacent air masses are relevant is through their vertical distribution that produces the requisite instability for the convective storm, but that instability is not directly related to the formation of tornadoes. Therefore, this article recommends that a greater effort be made to communicate accurately to the public the current scientific understanding of the conditions under which tornadoes are formed.

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Jonathan M. Davies, Charles A. Doswell III, Donald W. Burgess, and John F. Weaver

This paper considers a tornadic storm that struck south-central and eastern Kansas on 13 March 1990. Most of the devastation was associated with the first tornado from the storm as it passed through Hesston, Kansas. From the synoptic-scale and mesoscale viewpoints, the event was part of an outbreak of tornadoes on a day when the tornado threat was synoptically evident. Satellite imagery, combined with conventional data, suggest that the Hesston storm was affected by a preexisting, mesoscale outflow boundary laid down by morning storms. Radar and satellite data give clear indication of the supercellular character of the storm, despite limited radar data coverage.

Because of the considerable photographic coverage, several interesting features of the storm were recorded and are analyzed here. These include the following: 1) the movement and dissipation of a cloud band associated with an apparent rear-flank downdraft; 2) a transition from a rather large funnel through an apparent dissipation to the formation of a narrow funnel, during which the damage on the ground was continuous; and 3) a period of interaction between the first and second tornadoes.

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Erik N. Rasmussen, Jerry M. Straka, Robert Davies-Jones, Charles A. Doswell III, Frederick H. Carr, Michael D. Eilts, and Donald R. MacGorman

This paper describes the Verification of the Origins of Rotation in Tornadoes Experiment planned for 1994 and 1995 to evaluate a set of hypotheses pertaining to tornadogenesis and tornado dynamics. Observations of state variables will be obtained from five mobile mesonet vehicles, four mobile ballooning laboratories, three movie photography teams, portable Doppler radar teams, two in situ tornado instruments deployment teams, and the T-28 and National Atmospheric and Oceanic Administration P-3 aircraft. In addition, extensive use will be made of the new generation of observing systems, including the WSR-88D Doppler radars, demonstration wind profiler network, and National Weather Service rawinsondes.

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Pieter Groenemeijer, Tomáš Púčik, Alois M. Holzer, Bogdan Antonescu, Kathrin Riemann-Campe, David M. Schultz, Thilo Kühne, Bernold Feuerstein, Harold E. Brooks, Charles A. Doswell III, Hans-Joachim Koppert, and Robert Sausen

Abstract

The European Severe Storms Laboratory (ESSL) was founded in 2006 to advance the science and forecasting of severe convective storms in Europe. ESSL was a grassroots effort of individual scientists from various European countries. The purpose of this article is to describe the 10-yr history of ESSL and present a sampling of its successful activities. Specifically, ESSL developed and manages the only multinational database of severe weather reports in Europe: the European Severe Weather Database (ESWD). Despite efforts to eliminate biases, the ESWD still suffers from spatial inhomogeneities in data collection, which motivates ESSL’s research into modeling climatologies by combining ESWD data with reanalysis data. ESSL also established its ESSL Testbed to evaluate developmental forecast products and to provide training to forecasters. The testbed is organized in close collaboration with several of Europe’s national weather services. In addition, ESSL serves a central role among the European scientific and forecast communities for convective storms, specifically through its training activities and the series of European Conferences on Severe Storms. Finally, ESSL conducts wind and tornado damage assessments, highlighted by its recent survey of a violent tornado in northern Italy.

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