Search Results

You are looking at 1 - 5 of 5 items for

  • Author or Editor: Preston W. Leftwich Jr. x
  • All content x
Clear All Modify Search
Richard W. Anthony and Preston W. Leftwich Jr.

Abstract

Trends of tornado and severe thunderstorm watch verification for the period 1967–1990 are presented. Over the past 10 years the annual number of reported severe thunderstorm events has increased substantially. In comparison, the number of tornado events reported has remained relatively constant from year to year. During the period 1967 to 1990, the percentage of watches verifying has increased from 45% to 85%, while the probability of detection (POD) of severe local storm events has increased from about 0.35 to 0.50. Recent results show that the number of severe thunderstorm watches has steadily increased since 1985, the size of watches has slowly decreased, and lead time has slightly decreased.

Yearly fluctuations in tornado watch verification statistics appear to be best related to the number of outbreak tornadoes. Data suggest the Severe Local Storm Unit (SELS) performance in forecasting outbreak episodes and strong/violent tornadoes is improving at a faster rate than in forecasting isolated tornadoes. Improving trends in severe thunderstorm watch verification for the period 1967 to 1990 are also documented. In general, the results suggest a gradual improvement in forecast performance since the late 1960s. Several factors that impact the verification scores are also identified and discussed.

Full access
Edward W. Ferguson, Frederick P. Ostby, and Preston W. Leftwich Jr.

Abstract

A review of tornado activity in the United States during 1985 is presented. Annual statistics are compared with both recent and long-term values. Month-by-month highlights of tornado events are summarized. Meteorology patterns associated with three noteworthy tornado outbreaks are examined.

Full access
Edward W. Ferguson, Frederick P. Ostby, and Preston W. Leftwich Jr.

Abstract

A review of tornado activity in the United States during 1986 is presented. Annual statistics are compared with both recent and long-term values. Month-by-month highlights of tornado events are summarized. Meteorological patterns associated with four noteworthy tornado outbreaks are examined.

Full access
Edward W. Ferguson, Frederick P. Ostby, Preston W. Leftwich Jr., and John E. Hales Jr.

Abstract

Tornado events of 1984 are reviewed. Significant and interesting aspects of the 907 reported tornadoes are noted. Synoptic patterns associated with four noteworthy tornado days are examined.

Full access
Edward W. Ferguson, Frederick P. Ostby, Preston W. Leftwich Jr., William E. Carle, Steven F. Corfidi, Richard G. Cundy, and William D. Hirt

Abstract

Tornado events of 1983 are reviewed. Significant and interesting aspects of the 931 reported tornadoes are noted. Synoptic patterns associated with four noteworthy tornado days are examined.

Full access