An Analysis of Subdaily Severe Thunderstorm Probabilities for the United States

2020 ◽  
Vol 35 (1) ◽  
pp. 107-112 ◽  
Author(s):  
Makenzie J. Krocak ◽  
Harold E. Brooks
Keyword(s):  
United States ◽  
Spatial Scales ◽  
The United States ◽  
Severe Weather ◽  
Severe Thunderstorm ◽  
Probabilistic Information ◽  
Weather Events ◽  
Single Location ◽  
Spatiotemporal Scales ◽  
Definition Of

Abstract One of the challenges of providing probabilistic information on a multitude of spatiotemporal scales is ensuring that information is both accurate and useful to decision-makers. Focusing on larger spatiotemporal scales (i.e., from convective outlook to weather watch scales), historical severe weather reports are analyzed to begin to understand the spatiotemporal scales that hazardous weather events are contained within. Reports from the Storm Prediction Center’s report archive are placed onto grids of differing spatial scales and then split into 24-h convective outlook days (1200–1200 UTC). These grids are then analyzed temporally to assess over what fraction of the day a single location would generally experience severe weather events. Different combinations of temporal and spatial scales are tested to determine how the reference class (or the choice of what scales to use) alters the probabilities of severe weather events. Results indicate that at any given point in the United States on any given day, more than 95% of the daily reports within 40 km of the point occur in a 4-h period. Therefore, the SPC 24-h convective outlook probabilities can be interpreted as 4-h convective outlook probabilities without a significant change in meaning. Additionally, probabilities and threat periods are analyzed at each location and different times of year. These results indicate little variability in the duration of severe weather events, which allows for a consistent definition of an “event” for all locations in the continental United States.

scholarly journals Impact of Assimilating Dropsonde Observations from MPEX on Ensemble Forecasts of Severe Weather Events

2016 ◽  
Vol 144 (10) ◽  
pp. 3799-3823 ◽  
Author(s):  
Glen S. Romine ◽  
Craig S. Schwartz ◽  
Ryan D. Torn ◽  
Morris L. Weisman
Keyword(s):  
United States ◽  
Initial Conditions ◽  
Positive Impact ◽  
The United States ◽  
Early Morning ◽  
Severe Weather ◽  
Synoptic Scale ◽  
Ensemble Forecasts ◽  
Forecast Performance ◽  
Weather Events

Over the central Great Plains, mid- to upper-tropospheric weather disturbances often modulate severe storm development. These disturbances frequently pass over the Intermountain West region of the United States during the early morning hours preceding severe weather events. This region has fewer in situ observations of the atmospheric state compared with most other areas of the United States, contributing toward greater uncertainty in forecast initial conditions. Assimilation of supplemental observations is hypothesized to reduce initial condition uncertainty and improve forecasts of high-impact weather. During the spring of 2013, the Mesoscale Predictability Experiment (MPEX) leveraged ensemble-based targeting methods to key in on regions where enhanced observations might reduce mesoscale forecast uncertainty. Observations were obtained with dropsondes released from the NSF/NCAR Gulfstream-V aircraft during the early morning hours preceding 15 severe weather events over areas upstream from anticipated convection. Retrospective data-denial experiments are conducted to evaluate the value of dropsonde observations in improving convection-permitting ensemble forecasts. Results show considerable variation in forecast performance from assimilating dropsonde observations, with a modest but statistically significant improvement, akin to prior targeted observation studies that focused on synoptic-scale prediction. The change in forecast skill with dropsonde information was not sensitive to the skill of the control forecast. Events with large positive impact sampled both the disturbance and adjacent flow, akin to results from past synoptic-scale targeting studies, suggesting that sampling both the disturbance and adjacent flow is necessary regardless of the horizontal scale of the feature of interest.

scholarly journals The Association of the Elevated Mixed Layer with Significant Severe Weather Events in the Northeastern United States*

2010 ◽  
Vol 25 (4) ◽  
pp. 1082-1102 ◽  
Author(s):  
Peter C. Banacos ◽  
Michael L. Ekster
Keyword(s):  
United States ◽  
Mixed Layer ◽  
Trajectory Analysis ◽  
Source Region ◽  
Warm Season ◽  
The United States ◽  
Severe Weather ◽  
Lapse Rate ◽  
Northeastern United States ◽  
Weather Events

Abstract The occurrence of rare but significant severe weather events associated with elevated mixed-layer (EML) air in the northeastern United States is investigated herein. A total of 447 convective event days with one or more significant severe weather report [where significant is defined as hail 2 in. (5.1 cm) in diameter or greater, a convective gust of 65 kt (33 m s−1) or greater, and/or a tornado of F2 or greater intensity] were identified from 1970 through 2006 during the warm season (1 May–30 September). Of these, 34 event days (7.6%) were associated with identifiable EML air in regional rawinsondes preceding the event. Taken with two other noteworthy events in 1953 and 1969, a total of 36 significant severe weather events associated with EML air were studied via composite and trajectory analysis. Though a small percentage of the total, these 36 events compose a noteworthy list of historically significant derechos and tornadic events to affect the northeastern United States. It is demonstrated that plumes of EML air emanating from the Intermountain West in subsiding, anticyclonically curved flows can reinforce the capping inversion and maintain the integrity of the EML across the central United States over a few days. The EML plume can ultimately become entrained into a moderately fast westerly to northwesterly midtropospheric flow allowing for the plume’s advection into the northeastern United States. Resultant thermodynamic conditions in the convective storm environment are similar to those more typically observed closer to the EML source region in the Great Plains of the United States. In addition to composite and trajectory analysis, two case studies are employed to demonstrate salient and evolutionary aspects of the EML in such events. A lapse rate tendency equation is explored to put EML advection in context with other processes affecting lapse rate.

scholarly journals Extreme Weather and Forest Management in the Mid-Atlantic Region of the United States

2003 ◽  
Vol 20 (2) ◽  
pp. 61-70 ◽  
Author(s):  
David R. DeWalle ◽  
Anthony R. Buda ◽  
Ann Fisher
Keyword(s):  
Climate Change ◽  
United States ◽  
Forest Management ◽  
The United States ◽  
Extreme Weather ◽  
Severe Weather ◽  
Extreme Weather Events ◽  
Forest Land ◽  
Atlantic Region ◽  
Weather Events

Abstract Projected climate change could have major effects on forest management because of the potential for increased frequency, duration, and/or severity of extreme weather events. We surveyed public and private forestland management groups in the Mid-Atlantic region of the United States to better understand current interactions between extreme weather events and forest land management and to help predict future impacts. Our questionnaire addressed the importance and types of problems created by extreme weather events, the coping strategies employed to mitigate problems, and the overall economic effects of extreme weather. Responses were received from 322 forest managers/users (54% response rate) primarily representing state natural resources agencies, forestry consulting firms, large industrial forestry companies and smaller logging companies. Overall, respondents rated the impacts of extreme weather on their operations as low to modest; however, over 20% experienced “major” effects because of extreme weather over the past 10 yr. The highest rated impacts were: (1) reduced access to forestland because of flooding, deep snow, or wind- and ice-damaged trees; (2) increased costs for road and facility maintenance, and (3) direct damage to trees by wind, snow, or ice and subsequent effects on timber supplies and market prices. Mitigation strategies most commonly mentioned were switching of silvicultural systems and changing site preparation and planting schemes, but most respondents had not altered their management due to extreme weather. When asked about effects of a hypothetical 25% increase in severe weather, the most common mitigation strategy was increased investment in new equipment and facilities. Short-term economic impacts of severe weather varied between “supply increasing” conditions associated with increased tree damage and salvage operations and “supply decreasing” conditions related to reduced access to forest land. Increased severe weather due to climate change can be expected to have small to modest effects on forest management and users overall, but areas subjected to hurricanes and ice storms within the Mid-Atlantic region appear to be more sensitive to impacts of severe weather. North. J. Appl. For. 20(2):61–70.

scholarly journals Climatological Estimates of Daily Local Nontornadic Severe Thunderstorm Probability for the United States

2005 ◽  
Vol 20 (4) ◽  
pp. 577-595 ◽  
Author(s):  
Charles A. Doswell ◽  
Harold E. Brooks ◽  
Michael P. Kay
Keyword(s):  
United States ◽  
The United States ◽  
Severe Weather ◽  
Weather Event ◽  
Raw Data ◽  
Severe Thunderstorm ◽  
Annual Cycles ◽  
Wind Speeds ◽  
Spatial And Temporal Distributions ◽  
Severe Weather Event

Abstract The probability of nontornadic severe weather event reports near any location in the United States for any day of the year has been estimated. Gaussian smoothers in space and time have been applied to the observed record of severe thunderstorm occurrence from 1980 to 1994 to produce daily maps and annual cycles at any point. Many aspects of this climatology have been identified in previous work, but the method allows for the consideration of the record in several new ways. A review of the raw data, broken down in various ways, reveals that numerous nonmeteorological artifacts are present in the raw data. These are predominantly associated with the marginal nontornadic severe thunderstorm events, including an enormous growth in the number of severe weather reports since the mid-1950s. Much of this growth may be associated with a drive to improve warning verification scores. The smoothed spatial and temporal distributions of the probability of nontornadic severe thunderstorm events are presented in several ways. The distribution of significant nontornadic severe thunderstorm reports (wind speeds ≥ 65 kt and/or hailstone diameters ≥ 2 in.) is consistent with the hypothesis that supercells are responsible for the majority of such reports.

Populism and Liberal Democracy

2019 ◽  
Author(s):  
Takis S. Pappas
Keyword(s):  
United States ◽  
Liberal Democracy ◽  
The United States ◽  
Comprehensive Theory ◽  
The People ◽  
Original Definition ◽  
Key Issues ◽  
Great Relevance ◽  
Definition Of

Based on an original definition of modern populism as “democratic illiberalism” and many years of meticulous research, Takis Pappas marshals extraordinary empirical evidence from Argentina, Greece, Peru, Italy, Venezuela, Ecuador, Hungary, the United States, Spain, and Brazil to develop a comprehensive theory about populism. He addresses all key issues in the debate about populism and answers significant questions of great relevance for today’s liberal democracy, including: • What is modern populism and how can it be differentiated from comparable phenomena like nativism and autocracy? • Where in Latin America has populism become most successful? Where in Europe did it emerge first? Why did its rise to power in the United States come so late? • Is Trump a populist and, if so, could he be compared best with Venezuela’s Chávez, France’s Le Pens, or Turkey’s Erdoğan? • Why has populism thrived in post-authoritarian Greece but not in Spain? And why in Argentina and not in Brazil? • Can populism ever succeed without a charismatic leader? If not, what does leadership tell us about how to challenge populism? • Who are “the people” who vote for populist parties, how are these “made” into a group, and what is in their minds? • Is there a “populist blueprint” that all populists use when in power? And what are the long-term consequences of populist rule? • What does the expansion, and possibly solidification, of populism mean for the very nature and future of contemporary democracy? Populism and Liberal Democracy will change the ways the reader understands populism and imagines the prospects of liberal democracy.

scholarly journals Factors Influencing Land Values in the Presence of Suburban Sprawl

1974 ◽  
Vol 3 (1) ◽  
pp. 112-124 ◽  
Author(s):  
Bruce E. Lindsay ◽  
Cleve E. Willis
Keyword(s):  
United States ◽  
Rural Areas ◽  
The United States ◽  
Land Values ◽  
Suburban Sprawl ◽  
Factors Influencing ◽  
Definition Of

The spread of suburbs into previously rural areas has become commonplace in the United States. A rather striking aspect of this phenomenon has been the discontinuity which results. This aspect is often manifest in a haphazard mixture of unused and densely settled areas which has been described as “sprawl”. A more useful definition of suburban sprawl, its causes, and its consequences, is provided below in order to introduce the econometric objectives of this paper.

International Law and Administrative Insulation: A Comparison of Refugee Status Determination Regimes in the United States, Canada, and Australia

2012 ◽  
Vol 37 (04) ◽  
pp. 933-968 ◽  
Author(s):  
Rebecca Hamlin
Keyword(s):  
United States ◽  
International Law ◽  
Control Policy ◽  
The United States ◽  
Border Control ◽  
Refugee Status ◽  
Common Definition ◽  
Political Debates ◽  
Political Interference ◽  
Definition Of

International law provides nations with a common definition of a refugee, yet the processes by which countries determine who should be granted refugee status look strikingly different, even across nations with many institutional, cultural, geographical, and political similarities. This article compares the refugee status determination regimes of three popular asylum seeker destinations—the United States, Canada, and Australia. Despite these nations' similar border control policies, asylum seekers crossing their borders access three very different systems. These differences have less to do with political debates over admission and border control policy than with the level of insulation the administrative decision-making agency enjoys from political interference and judicial review. Bureaucratic justice is conceptualized and organized differently in different states, and so states vary in how they draw the line between refugee and nonrefugee.

scholarly journals A Total Lightning Trending Algorithm to Identify Severe Thunderstorms

2010 ◽  
Vol 27 (1) ◽  
pp. 3-22 ◽  
Author(s):  
Patrick N. Gatlin ◽  
Steven J. Goodman
Keyword(s):  
Severe Weather ◽  
Lightning Flash ◽  
Severe Thunderstorm ◽  
Critical Success ◽  
Severe Thunderstorms ◽  
Weather Events ◽  
Total Lightning ◽  
Jump Algorithm ◽  
Early Indication ◽  
Critical Success Index

Abstract An algorithm that provides an early indication of impending severe weather from observed trends in thunderstorm total lightning flash rates has been developed. The algorithm framework has been tested on 20 thunderstorms, including 1 nonsevere storm, which occurred over the course of six separate days during the spring months of 2002 and 2003. The identified surges in lightning rate (or jumps) are compared against 110 documented severe weather events produced by these thunderstorms as they moved across portions of northern Alabama and southern Tennessee. Lightning jumps precede 90% of these severe weather events, with as much as a 27-min advance notification of impending severe weather on the ground. However, 37% of lightning jumps are not followed by severe weather reports. Various configurations of the algorithm are tested, and the highest critical success index attained is 0.49. Results suggest that this lightning jump algorithm may be a useful operational diagnostic tool for severe thunderstorm potential.

Mahjong

2021 ◽  
Author(s):  
Annelise Heinz
Keyword(s):  
United States ◽  
American Culture ◽  
The United States ◽  
Jewish American ◽  
The Pacific ◽  
Women's Culture ◽  
History Of ◽  
American Heritage ◽  
Cultural Origins ◽  
Definition Of

Mahjong: A Chinese Game and the Making of Modern American Culture illustrates how the spaces between tiles and the moments between games have fostered distinct social cultures in the United States. When this mass-produced game crossed the Pacific it created waves of popularity over the twentieth century. Mahjong narrates the history of this game to show how it has created a variety of meanings, among them American modernity, Chinese American heritage, and Jewish American women’s culture. As it traveled from China to the United States and caught on with Hollywood starlets, high society, middle-class housewives, and immigrants alike, mahjong became a quintessentially American pastime. This book also reveals the ways in which women leveraged a game for a variety of economic and cultural purposes, including entrepreneurship, self-expression, philanthropy, and ethnic community building. One result was the forging of friendships within mahjong groups that lasted decades. This study unfolds in two parts. The first half is focused on mahjong’s history as related to consumerism, with a close examination of its economic and cultural origins. The second half explores how mahjong interwove with the experiences of racial inclusion and exclusion in the evolving definition of what it means to be American. Mahjong players, promoters, entrepreneurs, and critics tell a broad story of American modernity. The apparent contradictions of the game—as both American and foreign, modern and supposedly ancient, domestic and disruptive of domesticity—reveal the tensions that lie at the heart of modern American culture.

Styles of Leadership Training

G/C/T ◽  
1978 ◽  
Vol 1 (5) ◽  
pp. 9-12 ◽  
Author(s):  
A. Harry Passow
Keyword(s):  
United States ◽  
Gifted And Talented ◽  
Leadership Training ◽  
The United States ◽  
Gifted Child ◽  
Child Education ◽  
Definition Of

The United States Office of Education includes leadership in its comprehensive definition of giftedness. In this address, Dr. Passow discusses the concept of leadership in general and then shares with the reader his ideas on the specifics of developing leaders in the area of gifted child education. Originally presented at the Office of Gifted and Talented (U.S.O.E.) sponsored Institute on Leadership Training and the Gifted, Chicago, Illinois, June 3, 1978, Styles of Leadership Training is reproduced here for G/C/T's readers.

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