scholarly journals Future Changes in Hail Occurrence in the United States Determined through Convection-Permitting Dynamical Downscaling

2019 ◽  
Vol 32 (17) ◽  
pp. 5493-5509 ◽  
Author(s):  
Robert J. Trapp ◽  
Kimberly A. Hoogewind ◽  
Sonia Lasher-Trapp
Keyword(s):  
United States ◽  
Dynamical Downscaling ◽  
The United States ◽  
Lower Atmosphere ◽  
Eastern United States ◽  
Environmental Support ◽  
Convective Storms ◽  
Four Seasons ◽  
Central United States ◽  
Storm Frequency

AbstractThe effect of anthropogenically enhanced greenhouse gas concentrations on the frequency and intensity of hail depends on a range of physical processes and scales. These include the environmental support of the hail-generating convective storms and the frequency of their initiation, the storm volume over which hail growth is promoted, and the depth of the lower atmosphere conducive to melting. Here, we use high-resolution (convection permitting) dynamical downscaling to simultaneously account for these effects. We find broad geographical areas of increases in the frequency of large hail (≳35-mm diameter) over the United States, during all four seasons. Increases in very large hail (≳50-mm diameter) are mostly confined to the central United States, during boreal spring and summer. And, although increases in moderate hail (≳20-mm diameter) are also found throughout the year, decreases occur over much of the eastern United States in summer. Such decreases result from a projected decrease in convective-storm frequency. Overall, these results suggest that the annual U.S. hail season may begin earlier in the year, be lengthened by more than a week, and exhibit more interannual variability in the future.

scholarly journals Virulence of Puccinia triticina on Wheat in the United States in 1999

Plant Disease ◽  
2002 ◽  
Vol 86 (1) ◽  
pp. 15-19 ◽  
Author(s):  
D. L. Long ◽  
K. J. Leonard ◽  
M. E. Hughes
Keyword(s):  
United States ◽  
Great Plains ◽  
Gulf Coast ◽  
Puccinia Triticina ◽  
Leaf Rust Resistance ◽  
Distribution Patterns ◽  
The United States ◽  
Eastern United States ◽  
Ohio Valley ◽  
Central United States

Isolates of Puccinia triticina were obtained from wheat leaf collections made by cooperators throughout the United States and from surveys of wheat fields and nurseries in the Great Plains, Ohio Valley, and Gulf Coast states in 1999. Pathogenic races were determined from virulence/avirulence phenotypes on 14 host lines that are near-isogenic for leaf rust resistance. We found 58 races among 1,180 isolates in 1999. As in previous surveys, regional race distribution patterns showed that the central United States is a single epidemiological unit distinct from the eastern United States. The distinctive racial composition of collections from the Southeast, Northeast, and Ohio Valley indicates that populations of P. triticina in those areas are not closely connected, suggesting epidemics originate from localized overwintering sources.

scholarly journals Observations of Hail–Wind Ratios from Convective Storm Reports across the Continental United States

2020 ◽  
Vol 35 (2) ◽  
pp. 635-656 ◽  
Author(s):  
Matthew J. Bunkers ◽  
Steven R. Fleegel ◽  
Thomas Grafenauer ◽  
Chauncy J. Schultz ◽  
Philip N. Schumacher
Keyword(s):  
United States ◽  
Late Summer ◽  
Weather Forecast ◽  
Eastern United States ◽  
Convective Storm ◽  
Convective Storms ◽  
Warm Summer ◽  
Central United States ◽  
Spatiotemporal Analyses ◽  
Convective Mode

Abstract The objective of this study is to provide guidance on when hail and/or wind is climatologically most likely (temporally and spatially) based on the ratio of severe hail reports to severe wind reports, which can be used by National Weather Forecast (NWS) forecasters when issuing severe convective warnings. Accordingly, a climatology of reported hail-to-wind ratios (i.e., number of hail reports divided by the number of wind reports) for observed severe convective storms was derived using U.S. storm reports from 1955 to 2017. Owing to several temporal changes in reporting and warning procedures, the 1996–2017 period was chosen for spatiotemporal analyses, yielding 265 691 hail and 294 449 wind reports. The most notable changes in hail–wind ratios occurred around 1996 as the NWS modernized and deployed new radars (leading to more hail reports relative to wind) and in 2010 when the severe hail criterion increased nationwide (leading to more wind reports relative to hail). One key finding is that hail–wind ratios are maximized (i.e., relatively more hail than wind) during the late morning through midafternoon and in the spring (March–May), with geographical maxima over the central United States and complex/elevated terrain. Otherwise, minimum ratios occur overnight, during the late summer (July–August) as well as November–December, and over the eastern United States. While the results reflect reporting biases (e.g., fewer wind than hail reports in low-population areas but more wind reports where mesonets are available), meteorological factors such as convective mode and cool spring versus warm summer environments also appear associated with the hail–wind ratio climatology.

The Precipitation Response over the Continental United States to Cold Tropical Pacific Sea Surface Temperatures

2014 ◽  
Vol 27 (13) ◽  
pp. 5036-5055 ◽  
Author(s):  
Hailan Wang ◽  
Siegfried Schubert
Keyword(s):  
United States ◽  
Warm Season ◽  
The United States ◽  
Tropical Pacific ◽  
Eastern United States ◽  
North Atlantic Subtropical High ◽  
Sst Variability ◽  
The Pacific ◽  
Central United States ◽  
Atmospheric Circulation Anomalies

The dominant pattern of SST variability in the Pacific during its cold phase produces pronounced precipitation deficits over the continental United States throughout the annual cycle. This study investigates the observed physical and dynamical processes through which the cold Pacific pattern affects U.S. precipitation, particularly the causes for the peak dry impacts in fall, as well as the nature of the differences between the summer and fall responses. Results show that the peak precipitation deficit over the United States during fall is primarily due to reduced atmospheric moisture transport from the Gulf of Mexico into the central and eastern United States and secondarily a reduction in local evaporation from land–atmosphere feedback. The former is associated with a strong and systematic low-level northeasterly flow anomaly over the southeastern United States that counteracts the northwest branch of the climatological North Atlantic subtropical high. The above northeasterly anomaly is maintained by both diabatic heating anomalies in the nearby intra-American seas and diabatic cooling anomalies in the tropical Pacific. In contrast, the modest summertime precipitation deficit over the central United States is mainly an intensification of the local dry anomaly in the preceding spring from local land–atmosphere feedback; the rather weak and disorganized atmospheric circulation anomalies over and to the south of the United States make little contribution. An evaluation of the NASA Seasonal-to-Interannual Prediction Project (NSIPP-1) AGCM simulations shows it to be deficient in simulating the warm season tropical convection responses over the intra-American seas to the cold Pacific pattern and thereby the precipitation responses over the United States, a problem that appears to be common to many AGCMs.

scholarly journals Virulence of Puccinia triticina on Wheat in the United States from 1996 to 1998

Plant Disease ◽  
2000 ◽  
Vol 84 (12) ◽  
pp. 1334-1341 ◽  
Author(s):  
D. L. Long ◽  
K. J. Leonard ◽  
M. E. Hughes
Keyword(s):  
United States ◽  
Great Plains ◽  
Gulf Coast ◽  
Puccinia Triticina ◽  
Leaf Rust Resistance ◽  
Distribution Patterns ◽  
The United States ◽  
Eastern United States ◽  
Ohio Valley ◽  
Central United States

Isolates of Puccinia triticina were obtained from wheat leaf collections made by cooperators throughout the United States and from surveys of wheat fields and nurseries in the Great Plains, Ohio Valley, and Gulf Coast states in 1996, 1997, and 1998. Virulence-avirulence phenotypes were determined on 14 host lines that are near-isogenic for leaf rust resistance. We found 31 phenotypes among 277 single uredinial isolates in 1996, 56 phenotypes among 989 isolates in 1997, and 43 phenotypes among 989 isolates in 1998. As in previous surveys, regional race distribution patterns showed that the central United States is a single epidemiological unit distinct from the eastern United States. The distinctive racial composition of collections from the southeast, northeast, and Ohio Valley indicate that populations of P. triticina in those areas are not closely connected, suggesting that epidemics originate from localized overwintering sources.

scholarly journals A Five-Year Climatology of Elevated Severe Convective Storms in the United States East of the Rocky Mountains

2007 ◽  
Vol 22 (5) ◽  
pp. 1031-1044 ◽  
Author(s):  
Katherine L. Horgan ◽  
David M. Schultz ◽  
John E. Hales ◽  
Stephen F. Corfidi ◽  
Robert H. Johns
Keyword(s):  
United States ◽  
Rocky Mountains ◽  
Convective Available Potential Energy ◽  
The United States ◽  
Near Surface ◽  
Severe Storm ◽  
Convective Storms ◽  
South Central ◽  
Central United States ◽  
Diurnal Maximum

Abstract A 5-yr climatology of elevated severe convective storms was constructed for 1983–87 east of the Rocky Mountains. Potential cases were selected by finding severe storm reports on the cold side of surface fronts. Of the 1826 days during the 5-yr period, 1689 (91%) had surface fronts east of the Rockies. Of the 1689 days with surface fronts, 129 (8%) were associated with elevated severe storm cases. Of the 1066 severe storm reports associated with the 129 elevated severe storm cases, 624 (59%) were hail reports, 396 (37%) were wind reports, and 46 (4%) were tornado reports. A maximum of elevated severe storm cases occurred in May with a secondary maximum in September. Elevated severe storm cases vary geographically throughout the year, with a maximum over the south-central United States in winter to a central and eastern U.S. maximum in spring and summer. A diurnal maximum of elevated severe storm cases occurred at 2100 UTC, which coincided with the diurnal maximum of hail reports. The wind reports had a broad maximum during the daytime. Because the forecasting of hail from elevated storms typically does not pose as significant a forecast challenge as severe wind for forecasters and tornadoes from elevated storms are relatively uncommon, this study focuses on the occurrence of severe wind from elevated storms. Elevated severe storm cases that produce only severe wind reports occurred roughly 5 times a year. To examine the environments associated with cases that produced severe winds only, five cases were examined in more detail. Common elements among the five cases included elevated convective available potential energy, weak surface easterlies, and shallow near-surface stable layers (less than 100 hPa thick).

scholarly journals Severe Convective Storms across Europe and the United States. Part I: Climatology of Lightning, Large Hail, Severe Wind, and Tornadoes

2020 ◽  
Vol 33 (23) ◽  
pp. 10239-10261 ◽  
Author(s):  
Mateusz Taszarek ◽  
John T. Allen ◽  
Pieter Groenemeijer ◽  
Roger Edwards ◽  
Harold E. Brooks ◽  
...  
Keyword(s):  
United States ◽  
Great Plains ◽  
The United States ◽  
Maximum Activity ◽  
Severe Weather ◽  
Eastern United States ◽  
Convective Storms ◽  
Convective Systems ◽  
Lightning Detection ◽  
Mesoscale Convective

AbstractAs lightning-detection records lengthen and the efficiency of severe weather reporting increases, more accurate climatologies of convective hazards can be constructed. In this study we aggregate flashes from the National Lightning Detection Network (NLDN) and Arrival Time Difference long-range lightning detection network (ATDnet) with severe weather reports from the European Severe Weather Database (ESWD) and Storm Prediction Center (SPC) Storm Data on a common grid of 0.25° and 1-h steps. Each year approximately 75–200 thunderstorm hours occur over the southwestern, central, and eastern United States, with a peak over Florida (200–250 h). The activity over the majority of Europe ranges from 15 to 100 h, with peaks over Italy and mountains (Pyrenees, Alps, Carpathians, Dinaric Alps; 100–150 h). The highest convective activity over continental Europe occurs during summer and over the Mediterranean during autumn. The United States peak for tornadoes and large hail reports is in spring, preceding the maximum of lightning and severe wind reports by 1–2 months. Convective hazards occur typically in the late afternoon, with the exception of the Midwest and Great Plains, where mesoscale convective systems shift the peak lightning threat to the night. The severe wind threat is delayed by 1–2 h compared to hail and tornadoes. The fraction of nocturnal lightning over land ranges from 15% to 30% with the lowest values observed over Florida and mountains (~10%). Wintertime lightning shares the highest fraction of severe weather. Compared to Europe, extreme events are considerably more frequent over the United States, with maximum activity over the Great Plains. However, the threat over Europe should not be underestimated, as severe weather outbreaks with damaging winds, very large hail, and significant tornadoes occasionally occur over densely populated areas.

An Observational Examination of Long-Lived Supercells. Part I: Characteristics, Evolution, and Demise

2006 ◽  
Vol 21 (5) ◽  
pp. 673-688 ◽  
Author(s):  
Matthew J. Bunkers ◽  
Mark R. Hjelmfelt ◽  
Paul L. Smith
Keyword(s):  
United States ◽  
The United States ◽  
Eastern United States ◽  
North Central ◽  
The North ◽  
Central United States ◽  
Bow Echo ◽  
Primary Focus ◽  
Convective Mode

Abstract Observations of supercells and their longevity across the central and eastern United States are examined, with the primary focus on understanding the properties of long-lived supercells (defined as supercells lasting ≥4 h). A total of 224 long-lived supercells, occurring in 184 separate events, are investigated. These properties are compared with those of short-lived supercells (lifetimes ≤2 h) to determine the salient differences between the two classifications. A key finding is that long-lived supercells are considerably more isolated and discrete than short-lived supercells; as a result, the demise of a long-lived supercell (i.e., the end of the supercell phase) is often signaled by a weakening of the storm’s circulation and/or a rapid dissipation of the thunderstorm. In contrast, short-lived supercells commonly experience a demise linked to storm mergers and convective transitions (e.g., evolution to a bow echo). Also noteworthy, 36% of the long-lived supercell events were associated with strong or violent tornadoes (F2–F5), compared with only 8% for the short-lived supercell events. Evolutionary characteristics of long-lived supercells vary geographically across the United States, with the largest contrasts between the north-central United States and the Southeast. For example, 86% of the long-lived supercells across the north-central United States were isolated for most of their lifetime, whereas only 35% of those in the Southeast displayed this characteristic. Not surprisingly, the convective mode was discrete for 70% of the long-lived supercell events across the north-central United States, compared with 39% for the Southeast.

Convective Storms and the Insurance Industry: Challenges and Opportunities

2020 ◽  
Author(s):  
Kirsten D. Orwig
Keyword(s):  
United States ◽  
Tropical Cyclones ◽  
Insurance Industry ◽  
Property Values ◽  
Construction Materials ◽  
The United States ◽  
Building Code ◽  
Convective Storms ◽  
Challenges And Opportunities ◽  
Insured Loss

Convective storms affect countries worldwide, with billions in losses and dozens of fatalities every year. They are now the key insured loss driver in the United States, even after considering the losses sustained by tropical cyclones in 2017. Since 2008, total insured losses from convective storms have exceeded $10 billion per year. Additionally, these losses continue to increase year over year. Key loss drivers include increased population, buildings, vehicles, and property values. However, other loss drivers relate to construction materials and practices, as well as building code adoption and enforcement. The increasing loss trends pose a number of challenges for the insurance industry and broader society. These challenges are discussed, and some recommendations are presented.

System-wide seismic vulnerability of aging multiple-span multiple-girder bridges in low-to-moderate seismic hazard regions

2021 ◽  
Vol 37 (1_suppl) ◽  
pp. 1626-1651
Author(s):  
John E Lens M.EERI ◽  
Mandar M Dewoolkar ◽  
Eric M Hernandez M.EERI
Keyword(s):  
United States ◽  
Seismic Hazard ◽  
Cross Sections ◽  
Seismic Vulnerability ◽  
Time History ◽  
The United States ◽  
National Database ◽  
Eastern United States ◽  
Girder Bridges ◽  
The Status

This article describes the approach, methods, and findings of a quantitative analysis of the seismic vulnerability in low-to-moderate seismic hazard regions of the Central and Eastern United States for system-wide assessment of typical multiple span bridges built in the 1950s through the 1960s. There is no national database on the status of seismic vulnerability of bridges, and thus no means to estimate the system-wide damage and retrofit costs for bridges. The study involved 380 nonlinear analyses using actual time-history records matched to four representative low-to-medium hazard target spectra corresponding with peak ground accelerations from approximately 0.06 to 0.3 g. Ground motions were obtained from soft and stiff site seismic classification locations and applied to models of four typical multiple-girder with concrete bent bridges. Multiple-girder bridges are the largest single category, comprising 55% of all multiple span bridges in the United States. Aging and deterioration effects were accounted for using reduced cross-sections representing fully spalled conditions and compared with pristine condition results. The research results indicate that there is an overall low likelihood of significant seismic damage to these typical bridges in such regions, with the caveat that certain bridge features such as more extensive deterioration, large skews, and varied bent heights require bridge-specific analysis. The analysis also excludes potential damage resulting from liquefaction, flow-spreading, or abutment slumping due to weak foundation or abutment soils.

Force, Fraud, and Coercion—What Do They Mean? A Study of Victimization Experiences in a New Destination Latino Sex Trafficking Network

2016 ◽  
Vol 13 (5) ◽  
pp. 456-476 ◽  
Author(s):  
Lauren Copley Sabon
Keyword(s):  
United States ◽  
Law Enforcement ◽  
Social Constructionism ◽  
Sex Trafficking ◽  
The United States ◽  
Social Forces ◽  
Eastern United States ◽  
Latina Immigrants ◽  
Strict Interpretation ◽  
New Destination

In response to increasing Latino new destination migration in the United States, Latino sex trafficking networks have emerged in many of these areas. This article examines victimization experiences of Latina immigrants trafficked by a regional network operating in the Eastern United States drawn from law enforcement records and interviews with legal actors involved in the criminal case. The stories shared with law enforcement by the Latina victims gives insight into their lives, experiences in prostitution, and the operation of a trafficking/prostitution network (all lacking in the literature). Through the analytical frame of social constructionism, this research highlights how strict interpretation of force, fraud, coercion, and agency used to define “severe forms of trafficking” in the TVPA limits its ability to recognize many victimization experiences in trafficking situations at the hands of traffickers. The forms of coercion used in the criminal enterprise under study highlights the numerous ways it can be wielded (even without a physical presence) and its malleability as a concept despite legal definitional rigidity. The lack of legal recognition of the plurality of lived experiences in which agency and choice can be mitigated by social forces, structural violence, intersectional vulnerabilities, and the actions of others contributes to the scholarly critique of issues prosecuting trafficking cases under the TVPA and its strict legal definitions.

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