Showing papers by "Stanley A. Changnon published in 1978"

Urban Effects on Severe Local Storms at St. Louis

Abstract: As part of METROMEX, a five-year study of how St. Louis affects summer weather, studies were made of possible urban effects on severe local storm phenomena. Localized (within 40 km of the city) increases were found in various thunderstorm characteristics (about +10 to +115%), in hailstorm conditions (+3 to +330%), in various heavy rainfall characteristics (+35 to +100%) and strong gusts (+90 to +100%). No indication of effects on tornado activity was found. The more substantial percentage increases were found in the expressions of storm intensity (very frequent thunder, hailfall impact energy and high rainfall rates). Urban-related increases in severe local storm conditions appeared at midday, were greatest in the evening and ended by midnight. Urban-induced increases occurred with all synoptic weather types but were most frequent and intense with squall lines and cold fronts. Results suggest that urban-induced factors alter the microphysical and dynamic properties of clouds and storms.

Chicago Area Program: A Major New Atmospheric Effort

Abstract: A series of mesoscale meteorological research projects have developed since 1975 in the area over and around the south end of Lake Michigan. These regionally focused projects, under the label of the Chicago Area Program (CAP), are being performed by scientists from 12 research groups or universities using funds from a variety of state and federal agencies. Efforts to date have led to the installation and operation of a major rain gage network, other weather networks and sondes, several weather radars, meteorological aircraft, and a ship. This sizeable program is addressing five major study areas including lake meteorology, water resources and hydrometeorology, inadvertent weather modification, air pollution and its impacts, and severe weather. Multigroup field experiments and the exchange of data are coordinated at the scientist level.

Hail suppression and society.

Abstract: An interdisciplinary assessment of hail suppression in the past, present, and future has shown it to be currently scientifically uncertain but a potentially beneficial future technology. An established suppression technology would be widely adopted in the Great Plains, providing benefits to agriculture and secondarily to the American consumer. Development of a reliable technology will require a sizable longterm federal commitment to atmospheric and social research. Subcritical funding would be a mistake. Orderly future usage of hail suppression, with its scientific complexities and regional character, will necessitate development of governmental regulations, evaluation procedures, interstate arrangements, and means for compensating those who lose from modification.

Winter Storms and the Record-Breaking Winter in Illinois

Abstract: The winter of 1977–78 in Illinois was one of the most severe since residents began keeping records. A series of intense winter storms struck the state beginning in late November and continuing through March. How do these storms compare with previous winters?

Record winter storms in illinois, 1977-1978

Abstract: The Midwest, including Illinois, experienced in 1977-1978 its most severe winter since weather records began in the early 19th century. The major impact in Illinois came from a record-breaking number of 18 severe winter storms. In a normal year, only 4 storms occur. The record winter began with three snowstorms in late November and ended with an extremely damaging ice storm in late March. Unusual snow patterns occurred with several storms, and they lasted in Illinois much longer than usual. Weather conditions (low pressure centers) producing many of the storms were more often of Canadian origin than usual, and these lows had lower pressure and moved slower than normal, resulting in higher surface winds and longer lasting and hence more severe storms. Cold temperatures coupled with the frequent snowstorms resulted in record long-lasting snow cover with up to 120 days with 1 inch or more cover in northern Illinois and 90 days in southern Illinois. The storms led to deaths of 62 persons and injuries to more than 2,000. Utilities and communication systems suffered great losses due to damage to lines, poles and towers. Transportation losses included damaged vehicles, delayed shipments, and great delays in bus and airline service; however, railroads benefited with increased usage, and helicopters and snowmobiles proved valuable in rescue service. The local, state, and federal institutions were beset with enormous and costly problems, including care of roads and lost taxable income due to absenteeism.

Summary of METROMEX Volume 2

Abstract: This is the last of two volumes presenting the major findings from the 1971-1975METROMEX field operations at St. Louis. It presents climatological analyses of surface weather conditions, but primarily concerns those factors helping to describe the causes of the anomalies. Volume 1 covers spatial and temporal distributions of surface precipitation and severe storms, and impacts of urban-produced precipitation anomalies. Volume 2 describes relevant surface weather conditions including temperature, moisture, and winds, all influenced by the urban area. Urban influences extend well into the boundary layer affecting aerosol distributions, winds, and the thermodynamic structure, and often reach cloud base levels. Studies of modification of cloud and rain processes show urban-industrial influences on 1) initiation, local distribution, and characteristics of summer cumulus clouds; and 2) development of precipitation in clouds and the resulting surface rain entities.