DOCSLIB.ORG

Using Statistical Learning Approaches to Understand Trends and Variability of Tornadoes Across the Continental United States

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Using Statistical Learning Approaches to Understand Trends and Variability of Tornadoes Across the Continental United States City University of New York (CUNY) CUNY Academic Works Dissertations and Theses City College of New York 2020 Using statistical learning approaches to understand trends and variability of tornadoes across the continental United States Niloufar Nouri CUNY City College How does access to this work benefit ou?y Let us know! More information about this work at: https://academicworks.cuny.edu/cc_etds_theses/940 Discover additional works at: https://academicworks.cuny.edu This work is made publicly available by the City University of New York (CUNY). Contact: [email protected] Using statistical learning approaches to understand trends and variability of tornadoes across the continental United States by Niloufar Nouri A dissertation submitted to the Graduate Faculty in Civil Engineering in partial fulfillment of the requirements for the degree of Doctor of Philosophy The City College of New York The City University of New York 2020 © 2020 Niloufar Nouri All Rights Reserved i This manuscript has been read and accepted for the Graduate Faculty in Engineering in satisfaction of the dissertation requirement for the degree of Doctor of Philosophy Naresh Devineni, Chair of Examining Committee Date Ardie Walser, Associate Dean for Academic Affairs Date Examining Committee: Dr. Naresh Devineni, Department of Civil Engineering, the City College of New York, Dr. Reza Khanbilvardi, Department of Civil Engineering, the City College of New York, Dr. Nir Krakauer, Department of Civil Engineering, the City College of New York, Dr. Ardavan Yazdanbakhsh, Department of Civil Engineering, the City College of New York Dr. Valerie Were, Social Science Lead at the NOAA Center for Earth System Sciences and Remote Sensing Technologies THE CITY COLLEGE OF THE CITY UNIVERSITY OF NEW YORK ii Abstract The annual frequency of tornadoes during 1950-2018 across the major tornado-impacted states were examined and modeled using anthropogenic and large-scale climate covariates in a hierarchical Bayesian inference framework. Anthropogenic factors include increases in population density and better detection systems since the mid-1990s. Large-scale climate variables include El Niño Southern Oscillation (ENSO), Southern Oscillation Index (SOI), North Atlantic Oscillation (NAO), Pacific Decadal Oscillation (PDO), Arctic Oscillation (AO), and Atlantic Multi-decadal Oscillation (AMO). The model provides a robust way of estimating the response coefficients by considering pooling of information across groups of states that belong to Tornado Alley, Dixie Alley, and Other States, thereby reducing their uncertainty. The influence of the anthropogenic factors and the large-scale climate variables are modeled in a nested framework to unravel secular trend from cyclical variability. Population density explains the long-term trend in Dixie Alley. The step-increase induced due to the installation of the Doppler Radar systems explains the long-term trend in Tornado Alley. NAO and the interplay between NAO and ENSO explained the interannual to multi-decadal variability in Tornado Alley. PDO and AMO are also contributing to this multi-time scale variability. SOI and AO explain the cyclical variability in Dixie Alley. This improved understanding of the variability and trends in tornadoes should be of immense value to public planners, businesses, and insurance-based risk management agencies. The next phase of the study is focused on the spatial and temporal characteristics of large tornado outbreaks (LTOs) which are rated F2(EF2) or greater on Fujita (Enhanced Fujita) scale and has struck several counties in one day. A statistical assessment of changes in the LTOs clusters for two consecutive 30-year time periods 1950-1980 and 1988-2015 has been performed and the findings show a geographical shift of the central impact locations towards Southeast of the United States. The spatial shift is also accompanied by a reduction in cluster variance which suggests LTOs has become less dispersed between the two period. We investigate changes in tornado inter-arrival rate over time during the period of study using an exponential probability model. Results showed that the arrival rate has changed from 124 days during 1950-1980 to 164 days during 1977-2007, which means LTOs were less frequent in the recent period. The analyses performed in this study support previously reported findings in addition to providing complementary information on LTO clustering behavior and return period. Key Words: Statistical Learning, Hierarchical Bayesian Models, Tornado Data, ENSO, Machine Learning, Trend Analysis, Tornado Clusters, Spatio-temporal Analysis iii Acknowledgement Foremost, I would like to express my sincere appreciation and gratitude to my advisors professor Naresh Devineni and professor Reza Khanbilvardi for the continuous support of my PhD study, for their motivation, scientific advices and the insightful discussions about the research. Without their guidance and constant feedback this dissertation would not have been achievable. Besides my advisors, I would like to thank the rest of committee members Prof. Nir Krakauer, Dr. Valerie Were, Prof. Yazdanbakhsh, for their valuable comments and encouragement, which helped me to broaden my perspectives on this research. I would also like to say heartfelt thanks to my Mom, Dad and my sister for always believing in me and encouraging me to follow my dreams. This research was supported by department of Civil Engineering at the City College of New York and the U.S. Department of Energy Early CAREER Research Program Award # DE-SC0018124. Partial support is also provided by NOAA-EPP/MSI Grant #NA16SEC4810008. iv ردخت تو گر بار دانش بگیرد هب زری آوری چرخ نیلوفری ر ا خس " انصر رو " To Nasrin, Reza and Mina and to those who inspired me but will not read this… v Contents Chapter 1: Introduction ................................................................................................................... 5 1 Tornadoes in the United States ............................................................................................... 6 2 Research background .............................................................................................................. 7 2.1 Studies on (in)consistency in the U.S. tornado data ......................................................... 7 2.2 Studies on tornado frequency and trends ......................................................................... 9 2.3 Statistical models for tornado variabilities ..................................................................... 10 2.4 Studies on the impact of climate variables on tornado activity ...................................... 11 3 The gap in previous research ................................................................................................ 13 4 Research scope ...................................................................................................................... 13 Chapter 2: Explaining the trends and variability in the United States tornado records using climate teleconnections and shifts in observational practices ....................................................... 15 Abstract ......................................................................................................................................... 16 1. Introduction ............................................................................................................................. 1 2. Methods................................................................................................................................... 8 2.1. Data .................................................................................................................................. 8 2.1.1. Tornados ................................................................................................................... 8 2.1.2. Population Density .................................................................................................. 12 2.1.3. Large-scale Climate ................................................................................................ 12 2.2. Analysis and Modeling................................................................................................... 12 vi 2.2.1. Principal Component Analysis and Wavelet Decomposition ................................. 13 2.2.2. Hierarchical Bayesian Models ................................................................................ 14 3. Results ................................................................................................................................... 18 3.1. Explaining the Variance ................................................................................................. 18 3.2. Inference of the Significant Predictors ........................................................................... 26 4. Summary ............................................................................................................................... 35 Chapter 3: Investigating the spatial manifestation and rate of arrival of large tornado outbreaks 38 Abstract ......................................................................................................................................... 39 1 Introduction ........................................................................................................................... 40 2 Method .................................................................................................................................. 42 2.1
Load more

Recommended publications
  • A Climatology and Comparison of Parameters for Significant Tornado
    106 WEATHER AND FORECASTING VOLUME 27 A Climatology and Comparison of Parameters for Significant Tornado Events in the United States JEREMY S. GRAMS AND RICHARD L. THOMPSON NOAA/NWS/Storm Prediction Center, Norman, Oklahoma DARREN V. SNIVELY Department of Geography, Ohio University, Athens, Ohio JAYSON A. PRENTICE Department of Geological and Atmospheric Sciences, Iowa State University, Ames, Iowa GINA M. HODGES AND LARISSA J. REAMES School of Meteorology, University of Oklahoma, Norman, Oklahoma (Manuscript received 18 January 2011, in final form 30 August 2011) ABSTRACT A sample of 448 significant tornado events was collected, representing a population of 1072 individual tornadoes across the contiguous United States from 2000 to 2008. Classification of convective mode was assessed from radar mosaics for each event with the majority classified as discrete cells compared to quasi- linear convective systems and clusters. These events were further stratified by season and region and com- pared with a null-tornado database of 911 significant hail and wind events that occurred without nearby tornadoes. These comparisons involved 1) environmental variables that have been used through the past 25– 50 yr as part of the approach to tornado forecasting, 2) recent sounding-based parameter evaluations, and 3) convective mode. The results show that composite and kinematic parameters (whether at standard pressure levels or sounding derived), along with convective mode, provide greater discrimination than thermodynamic parameters between significant tornado versus either significant hail or wind events that occurred in the absence of nearby tornadoes. 1. Introduction severe thunderstorms and tornadoes (e.g., Bluestein 1999; Davies-Jones et al. 2001; Wilhelmson and Wicker Severe weather forecasting has evolved considerably 2001).
    [Show full text]
  • Twisters in Two Cities: Stuctural Ritualization
    TWISTERS IN TWO CITIES: STUCTURAL RITUALIZATION THEORY AND DISASTERS By KEVIN M. JOHNSON Bachelor of Arts in Psychology Northeastern State University Tahlequah, Oklahoma 2011 Master of Science in Sociology Oklahoma State University Stillwater, Oklahoma 2013 Submitted to the Faculty of the Graduate College of the Oklahoma State University in partial fulfillment of the requirements for the Degree of DOCTOR OF PHILOSOPHY May, 2019 TWISTERS IN TWO CITIES: STRUCTURAL RITUALIZATION THEORY AND DISASTERS Dissertation Approved: Dr. Duane A. Gill Dissertation Adviser Dr. J. David Knottnerus Dr. Monica Whitham Dr. Alex Greer ii ACKNOWLEDGEMENTS I would first like to thank my committee members – Dr. Duane Gill, Dr. J. David Knottnerus, Dr. Monica Whitham, and Dr. Alex Greer – for their insight and support throughout the writing of this dissertation. I am particularly grateful for Dr. Gill and Dr. Knottnerus, who have invested tremendous time and energy in mentoring and helping me develop as a sociologist and a thinker. I have had the privilege of working with some of my academic heroes on this project, and feel very fortunate to be able to make that claim. I would also like to thank my fellow graduate colleagues, Dr. Dakota Raynes, Christine Thomas, and many others, who were always willing to discuss various issues related to this research and countless other topics when needed. Your contributions to this work extend beyond the words on the page – thank you! Finally, I would like to acknowledge my family for their unwavering support and confidence in me throughout this process. Kasey, Gabriel, Ewok, and Leia: you have been my foundation, particularly in the toughest times, and I hope you all feel the joy of this accomplishment because it could not have happened without you.
    [Show full text]
  • Article a Climatological Perspective on the 2011 Alabama Tornado
    Chaney, P. L., J. Herbert, and A. Curtis, 2013: A climatological perspective on the 2011 Alabama tornado outbreak. J. Operational Meteor., 1 (3), 1925, doi: http://dx.doi.org/10.15191/nwajom.2013.0103. Journal of Operational Meteorology Article A Climatological Perspective on the 2011 Alabama Tornado Outbreak PHILIP L. CHANEY Auburn University, Auburn, Alabama JONATHAN HERBERT and AMY CURTIS Jacksonville State University, Jacksonville, Alabama (Manuscript received 23 January 2012; in final form 17 September 2012) ABSTRACT This paper presents a comparison of the recent 27 April 2011 tornado outbreak with a tornado climatology for the state of Alabama. The climatology for Alabama is based on tornadoes that affected the state during the 19812010 period. A county-level risk index is produced from this climatology. Tornado tracks from the 2011 outbreak are mapped and compared with the climatology and risk index. There were 62 tornadoes in Alabama on 27 April 2011, including many long-track and intense tornadoes. The event resulted in 248 deaths in the state. The 2011 outbreak is also compared with the April 1974 tornado outbreak in Alabama. 1. Introduction population density (Gagan et al. 2010; Dixon et al. 2011). Tornadoes have been documented in every state in Alabama is affected in the spring and fall by the United States and on every continent except midlatitude cyclones, often associated with severe Antarctica. The United States has by far the most weather and tornadoes. During summer and fall tornado reports annually of any country, averaging tornadoes also can be produced by tropical cyclones. A about 1,300 yr-1.
    [Show full text]
  • Withstanding the Winds Resilience Science
    Level Two or Three 4-H Science, Engineering and Technology Project Activity Guide Withstanding the Winds Resilience Science Effects of High Wind High-wind events can form slowly offshore or very rapidly over land. In most cases, there is not enough time to protect your home before a storm strikes. This is why construction should be adapted to withstand regional vulnerabilities. High - Wind Events and Hazards Hurricanes Tornadoes Cat. 1: 74-95 mph EF0: 65-85 mph Cat. 2: 96-110 mph EF1: 86-110 mph Cat. 3: 111-129 mph EF2: 111-135 mph Level: Cat. 4: 130-156 mph EF3: 136-165 mph Two or Three Cat. 5: 157 or higher EF4: 166-200 mph EF5: 200 or higher Life skills: Decision making Thunderstorms Wind-Driven Hail Problem solving Responsibility Awareness Goal: Educate young people about wind -resistant construction and mitigation Along with rain and lightning, Hail is a common result of winds produced during tornadoes and/or thunderstorms. Authors: thunderstorms can range from 30 It can range from the size of a Shandy Heil mph to 100 mph. marble to a softball. Damage Identification Hurricane-force winds, tornadoes and hail produce different types of damage to buildings. Read the storm damage clues below and draw a line to the picture that shows the appropriate type of damage. Hurricane High-wind damage can blow off wall siding and shingles, produce wind-borne debris capable of breaking windows and, in some cases, cause structural damage to the walls and roof. Hail Damage includes broken windows and dents or punctures in wall siding and shingles.
    [Show full text]
  • Illinois Tornadoes Prior to 1916
    Transactions of the Illinois State Academy of Science (1993), Volume 86, 1 and 2, pp. 1 - 10 Illinois Tornadoes Prior to 1916 Wayne M. Wendland Illinois State Water Survey Champaign IL Herbert Hoffman National Weather Service Romeoville IL ABSTRACT An effort to chronicle Illinois tornadoes occurring prior to 1916 is summarized. From the more than 440 total Illinois tornado occurrences identified in the literature from that period, the list was culled to 325 individual events. Annual and mean monthly frequencies are shown and discussed relative to the modern record. The present tornado data set includes location, time, and to a lesser extent, number injured, number killed and damage for each tornado event. Prominent tornadoes from the record are discussed, as data are available. INTRODUCTION The history of tornadoes in Illinois is rather well known since the mid-1950s (e.g., see Wilson & Changnon, 1971; and Wendland & Guinan, 1988). That record is believed to be essentially complete since the U.S. Weather Bureau inaugurated a concerted effort to record all such events at that time. Earlier,tornado accounts may be suspect since a record of such a small scale event is largely dependent on population density, awareness, and maintenance of a continuous record. Although the U.S. Army Signal Corps and U.S. Weather Bureau accepted tornado information for archival purposes through the years, a complete and continuous record only exists since the mid-1950s. In spite of the incomplete nature of earlier tornado records, useful information of a climatological nature can be gleaned. This paper represents an initial attempt to document the record of Illinois tornadoes prior to 1916.
    [Show full text]
  • Dixie Alley: Fact Or Fallacy : an in Depth Analysis of Tornado Distribution in Alabama
    Mississippi State University Scholars Junction Theses and Dissertations Theses and Dissertations 1-1-2004 Dixie alley: Fact or Fallacy : An In Depth Analysis of Tornado Distribution in Alabama Kristin Nichole Hurley Follow this and additional works at: https://scholarsjunction.msstate.edu/td Recommended Citation Hurley, Kristin Nichole, "Dixie alley: Fact or Fallacy : An In Depth Analysis of Tornado Distribution in Alabama" (2004). Theses and Dissertations. 1549. https://scholarsjunction.msstate.edu/td/1549 This Graduate Thesis - Open Access is brought to you for free and open access by the Theses and Dissertations at Scholars Junction. It has been accepted for inclusion in Theses and Dissertations by an authorized administrator of Scholars Junction. For more information, please contact [email protected]. DIXIE ALLEY:FACT OR FALLACY AN IN DEPTH ANALYSIS OF TORNADO DISTRIBUTION IN ALABAMA By Kristin Nichole Hurley A Thesis Submitted to the Faculty of Mississippi State University in Partial Fulfillment of the Requirements for the Degree of Master of Science in Geoscience in the Department of Geosciences Mississippi State, Mississippi May 2004 Copyright by Kristin Nichole Hurley 2004 DIXIE ALLEY: FACT OR FALLACY AN IN DEPTH ANALYSIS OF TORNADO DISTRIBUTION IN ALABAMA By Kristin Nichole Hurley ______________________________ ______________________________ Michael E. Brown Charles L. Wax Assistant Professor of Geosciences Professor of Geosciences (Director of Thesis) (Committee Member) ______________________________ ______________________________ John C. Rodgers, III John E. Mylroie Assistant Professor of Geosciences Graduate Coordinator of the Department (Committee Member) of Geosciences ______________________________ ______________________________ Mark S. Binkley Philip B. Oldham Professor and Head of the Department of Dean and Professor of the College of Geosciences Arts and Sciences Name: Kristin Nichole Hurley Date of Degree: May 8, 2004 Institution: Mississippi State University Major Field: Geoscience Major Professor: Dr.
    [Show full text]
  • Community Organizations Under Stress: a Study of Interorganizational Communication Networks During Natural Disasters
    71-17,967 BROUILLETTE, John Robert, 1935- COMMUNITY ORGANIZATIONS UNDER STRESS: A STUDY OF INTERORGANIZATIONAL COMMUNICATION NETWORKS DURING NATURAL DISASTERS. The Ohio State University, Ph.D., 1970 Sociology, general University Microfilms,A XEROX Company , Ann Arbor. Michigan COMMUNITY ORGANIZATIONS UNDER STRESS: A STUDY OF INTERORGANIZATIONAL COMMUNICATION NETWORKS DURING NATURAL DISASTERS DISSERTATION Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of The Ohio State University By John Robert Brouillette, B.S., M.A. ****** The Ohio State University 1970 Approved by t Adviser* /} Department of SociofogyDepartment Sociology ACKNOWLEDGMENTS The research in this dissertation was supported in part by PHS Grant 5 R01 MH 15399-02 from the Center for Studies of Mental Health and Social Problems, Applied Research Branch, National Insti­ tute of Mental Health. Many faculty members have been instrumental in assisting me throughout my graduate studies. Foremost among them was my adviser, Dr. Russell R. Dynes, whose untiring guidance, encouragement, and support were always forthcoming when they were needed most. Also I would like to express my sincere appreciation to Dr. E. L. Quar- antelli who, with Dr. Dynes, provided an invaluable graduate training program at the Disaster Research Center which allowed me to apply and advance the sociological knowledge I had been exposed to earlier in formal course work. A special word of thanks belongs to Dr. John F. Cuber who introduced me to The Ohio State University as a teaching assistant under him and who ushered me out when he sat on my final Doctoral oral examination. He has been a significant influence and inspiration to me throughout my graduate program.
    [Show full text]
  • A Background Investigation of Tornado Activity Across the Southern Cumberland Plateau Terrain System of Northeastern Alabama
    DECEMBER 2018 L Y Z A A N D K N U P P 4261 A Background Investigation of Tornado Activity across the Southern Cumberland Plateau Terrain System of Northeastern Alabama ANTHONY W. LYZA AND KEVIN R. KNUPP Department of Atmospheric Science, Severe Weather Institute–Radar and Lightning Laboratories, Downloaded from http://journals.ametsoc.org/mwr/article-pdf/146/12/4261/4367919/mwr-d-18-0300_1.pdf by NOAA Central Library user on 29 July 2020 University of Alabama in Huntsville, Huntsville, Alabama (Manuscript received 23 August 2018, in final form 5 October 2018) ABSTRACT The effects of terrain on tornadoes are poorly understood. Efforts to understand terrain effects on tornadoes have been limited in scope, typically examining a small number of cases with limited observa- tions or idealized numerical simulations. This study evaluates an apparent tornado activity maximum across the Sand Mountain and Lookout Mountain plateaus of northeastern Alabama. These plateaus, separated by the narrow Wills Valley, span ;5000 km2 and were impacted by 79 tornadoes from 1992 to 2016. This area represents a relative regional statistical maximum in tornadogenesis, with a particular tendency for tornadogenesis on the northwestern side of Sand Mountain. This exploratory paper investigates storm behavior and possible physical explanations for this density of tornadogenesis events and tornadoes. Long-term surface observation datasets indicate that surface winds tend to be stronger and more backed atop Sand Mountain than over the adjacent Tennessee Valley, potentially indicative of changes in the low-level wind profile supportive to storm rotation. The surface data additionally indicate potentially lower lifting condensation levels over the plateaus versus the adjacent valleys, an attribute previously shown to be favorable for tornadogenesis.
    [Show full text]
  • Hazard Mitigation Plan Lapeer County, MI
    + ddddddddd Hazard Mitigation Plan Lapeer County, MI 2015 This document was prepared by the2013 GLS Region V Planning and Development CommissionThis document was preparedstaff byin the collaboration Lapeer County Office of Emergency with Managementthe Lapeer County Office of Emergencyin collaboration with GLSManagement Region V Planning and. Development Commission staff. TABLE OF CONTENTS I. Introduction A. Introduction ..................................................................................... 1 B. Goals and Objectives ....................................................................... 5 C. Historical Perspective ....................................................................... 5 D. Regional Setting ............................................................................... 8 E. Climate ............................................................................................. 9 F. Population and Housing .................................................................. 11 G. Land Use Characteristics ................................................................. 14 H. Economic Profile.............................................................................. 14 I. Employment................................................................................... 15 J. Community Facilities/Public Safety ................................................. 16 K. Fire Protection and Emergency Dispatch Services .......................... 16 L. Utilities, Sewer, and Water ............................................................
    [Show full text]
  • Florida's Tornado Climatology: Occurrence Rates, Casualties, and Property Losses Emily Ryan
    Florida State University Libraries Electronic Theses, Treatises and Dissertations The Graduate School 2018 Florida's Tornado Climatology: Occurrence Rates, Casualties, and Property Losses Emily Ryan Follow this and additional works at the DigiNole: FSU's Digital Repository. For more information, please contact [email protected] FLORIDA STATE UNIVERSITY COLLEGE OF SOCIAL SCIENCES & PUBLIC POLICY FLORIDA'S TORNADO CLIMATOLOGY: OCCURRENCE RATES, CASUALTIES, AND PROPERTY LOSSES By EMILY RYAN A Thesis submitted to the Department of Geography in partial fulfillment of the requirements for the degree of Master of Science 2018 Copyright c 2018 Emily Ryan. All Rights Reserved. Emily Ryan defended this thesis on April 6, 2018. The members of the supervisory committee were: James B. Elsner Professor Directing Thesis David C. Folch Committee Member Mark W. Horner Committee Member The Graduate School has verified and approved the above-named committee members, and certifies that the thesis has been approved in accordance with university requirements. ii TABLE OF CONTENTS List of Tables . v List of Figures . vi Abstract . viii 1 Introduction 1 1.1 Definitions . 1 1.2 Where Tornadoes Occur . 3 1.3 Tornadoes in Florida . 4 1.4 Goals and Objectives . 6 1.5 Tornado Climatology as Geography . 6 1.6 Outline of the Thesis . 7 2 Data and Methods 9 2.1 Data . 9 2.1.1 Tornado Data . 9 2.1.2 Tropical Cyclone Tornado Data . 11 2.1.3 Property Value Data . 13 2.2 Statistical Methods . 15 2.3 Analysis Variables . 16 2.3.1 Occurrence Rates . 16 2.3.2 Casualties . 16 2.3.3 Property Exposures .
    [Show full text]
  • Explaining the Trends and Variability in the United States Tornado Records
    www.nature.com/scientificreports OPEN Explaining the trends and variability in the United States tornado records using climate teleconnections and shifts in observational practices Niloufar Nouri1*, Naresh Devineni1,2*, Valerie Were2 & Reza Khanbilvardi1,2 The annual frequency of tornadoes during 1950–2018 across the major tornado-impacted states were examined and modeled using anthropogenic and large-scale climate covariates in a hierarchical Bayesian inference framework. Anthropogenic factors include increases in population density and better detection systems since the mid-1990s. Large-scale climate variables include El Niño Southern Oscillation (ENSO), Southern Oscillation Index (SOI), North Atlantic Oscillation (NAO), Pacifc Decadal Oscillation (PDO), Arctic Oscillation (AO), and Atlantic Multi-decadal Oscillation (AMO). The model provides a robust way of estimating the response coefcients by considering pooling of information across groups of states that belong to Tornado Alley, Dixie Alley, and Other States, thereby reducing their uncertainty. The infuence of the anthropogenic factors and the large-scale climate variables are modeled in a nested framework to unravel secular trend from cyclical variability. Population density explains the long-term trend in Dixie Alley. The step-increase induced due to the installation of the Doppler Radar systems explains the long-term trend in Tornado Alley. NAO and the interplay between NAO and ENSO explained the interannual to multi-decadal variability in Tornado Alley. PDO and AMO are also contributing to this multi-time scale variability. SOI and AO explain the cyclical variability in Dixie Alley. This improved understanding of the variability and trends in tornadoes should be of immense value to public planners, businesses, and insurance-based risk management agencies.
    [Show full text]
  • Severe Weather Preparedness by Katie Moore & Alex Lamers
    READ ABOUT HOW YOU CAN BECOME PREPARED FOR ISSUE 10 Spring 2015 SEVERE WEATHER………..1 EMPLOYEE SPOTLIGHT: MEET JOURNEYMAN FORE- CASTER, ALEX LAMERS ... 2 CLIMATE RECAP FOR WINTER AND OUTLOOK FOR SPRING ........................ 4 Tallahassee NEWS AND NOTES FROM YOUR LOCAL NATIONAL WEATHER SERVICE OFFICE . topics The National Weather Service (NWS) office in Tallahassee, FL provides weather, hydrologic, and climate forecasts and warnings for Southeast Ala- bama, Southwest & South Central Georgia, the Florida Panhandle and Big Bend, and the adjacent Gulf of Mexico coastal waters. Our primary mission is Severe Weather Preparedness By Katie Moore & Alex Lamers Although the tornadoes in “Dixie Alley” tend to have lower maximum During a Tornado wind speeds than those in the Plains, they can be even deadlier. Many tor- nadoes that impact our area are rain-wrapped and often occur at night, ob- Get in - get into a sturdy build- scuring people’s ability to see them coming. We also have more terrain and ing and put as many walls be- denser tree coverage than out in the Plains, which also makes them more tween you and the outside as difficult to see coming. Furthermore, more people live in mobile homes in possible Dixie Alley than in the Plains and most people in the south do not have basements or access to underground shelter. Get down - get as low in the building as possible- the base- The best time to create a severe weather safety plan is before weather ment or the lowest floor strikes. Here are some tips for what to do before, during, and after a torna- do.
    [Show full text]