v

Contents

Preface xiii

Acknowledgements xvii

Biographies xviii

Chapter 1

Properties of the Atmosphere 1Key Words 1

Temperature 3

FUN FACT Degree-days—A Measure of Energy Consumption 4

Pressure 7

FUN FACT Dangerous Weather IsAlways Nearby 8

Moisture 10

Moisture Variables 10

FUN FACT Extreme Indoor Relative Humidity in Winter 13

Phase Changes and Clouds 14

Wind 16

Test Your Understanding 17

Test Your Problem-Solving Skills 18

Chapter 2

Meteorological Measurements 21Key Words 21

Surface Measurements 23

SCIENCE AND TECHNOLOGY A Historical Perspective on Technology in Meteorology 23

SCIENCE AND TECHNOLOGY The U.S. National Weather Service 24

Rawinsondes 26

ADVANCED TOPIC Hodographs 30

Radar 30

ADVANCED TOPIC The Doppler Shift and Doppler Radars 33

SCIENCE AND TECHNOLOGY Doppler Radar and Tornadoes 34

SCIENCE AND TECHNOLOGY Radar Estimated Precipitation and Flood Forecasting 35

Satellites and Satellite Imagery 36

SCIENCE AND TECHNOLOGY Soundings from GPS and COSMIC Satellites 38

Lightning Detection 41

Test Your Understanding 42

Test Your Problem-Solving Skills 43

Chapter 3

Weather Maps 45Key Words 45

The Surface Station Model and Surface Weather Maps 46

Pressure as a Vertical Coordinate 48

METEOROLOGY & MAPS Reading Maps 49

Constant Pressure Maps 49

ADVANCED TOPIC 500 mb Maps and Vorticity 53

METEOROLOGY & MAPS Upper Air Maps and the Internet 56

Cross Sections 56

Test Your Understanding 57

Test Your Problem-Solving Skills 58

Chapter 4

Forecasting and Simulating Hazardous Weather 59

Key Words 59

Weather Forecasting Using Computer Models 61

Initializing and Running a Model 62

SCIENCE AND TECHNOLOGY The Origin of Numerical Weather Prediction 67

Output from Models 67

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Limitations of Weather Forecast Models 70

The Mathematical Equations Approximate Some Atmospheric Processes 70

ADVANCED TOPIC Synopsis of Operational NWP Models 71

Errors in the Initial Weather Conditions 72

Inadequate Resolution 72

Research Models 75

FUN FACT A Perspective on Weather Prediction 77

Test Your Understanding 77

Test Your Problem-Solving Skills 78

Chapter 5

Climate and Global Change 81Key Words 81

Controls of Climate 82

Seasonal Cycle 83

Pressure Patterns 85

Land and Its Effects on Climate 86

Causes of Climate Change 89

ADVANCED TOPIC Determining Past Climates 90

Long Term (Millions of Years) 91

Medium Term (Thousands to Hundreds of Thousands of Years) 91

FUN FACT Ice-Age Weather 93

Short Term (Several Years to Hundreds of Years) 94

EXTREME EVENT The Year without a Summer 96

Recent and Ongoing Climate Change 98

Future Climate Change 100

ADVANCED TOPIC Retreating Sea Ice and Midlatitude Weather 106

Test Your Understanding 107

Test Your Problem-Solving Skills 108

Chapter 6

Atmospheric Stability 111Key Words 111

The Concept of Stability 112

Lapse Rates 114

Determining Stability 115

Mechanisms That Cause Air to Rise 121

FUN FACT Thunderstorms Over Mountains 123

Stability Indices 124

ADVANCED TOPIC Stability, Capping Inversions and Severe Storms 125

Test Your Understanding 127

Test Your Problem-Solving Skills 128

Chapter7

Forces and Force Balances 131Key Words 131

Forces That Affect Atmospheric Motion 132

The Pressure Gradient Force 132

FUN FACT Experience the Change of Pressure Across a Hurricane Eyewall 135

The Gravitational Force 135

The Frictional Force 135

The Coriolis Force 136

Newton’s Laws of Motion 140

Force Balances 141

Hydrostatic Balance 141

Geostrophic Balance 142

Summary of Forces and Force Balances 144

Geostrophic Balance and the Jet Stream 144

STORMS AND SOCIETY Flying and the Jet Stream 145

Test Your Understanding 147

Test Your Problem-Solving Skills 148

Chapter 8

The Development of High- and Low-Pressure Systems 151

Key Words 151

Force Imbalances 152

Curved Flow 154

Jet Streaks 157

ADVANCED TOPIC Multiple Jet streaks 159

Combined Effect of Curvature and Jet Streaks 160

The Friction Layer 161

Effects of Heating and Cooling 163

Test Your Understanding 167

Test Your Problem-Solving Skills 168

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Chapter 9

Airmasses and Fronts 171Key Words 171

Airmasses 172

FUN FACT No Tornadoes from Clashing Airmasses 172

Fronts 174

Cold Fronts 174

Warm Fronts 175

Stationary Fronts 177

Occluded Fronts 177

Dry Lines 178

Upper-Level Fronts 180

Finding Fronts on Weather Maps 182

METEOROLOGY & MAPS The Origins of Fronts on Maps 182

Test Your Understanding 185

Test Your Problem-Solving Skills 185

Chapter 10

Extratropical Cyclones Forming East of the Rocky Mountains 189

Key Words 189

The Environment Prior to the Development of a Cyclone 191

The Initial Development of the Cyclone 192

Initial Movement of the Airmasses 193

Early Weather Along the Fronts 194

East of the Cyclone Center 195

South of the Cyclone Center 195

Upper-Level Front, Dry Line, and Cold Front Present 196

A Pacific Front: The Upper-Level Front and Dry Line Aligned 197

Cold Front Only 198

Northwest of Cyclone Center 198

Summary of Early Weather 198

Storm Intensification 198

ADVANCED TOPIC The Environment on the Great Plains During Cyclone Formation 199

The Mature Cyclone 201

FUN FACT Alberta Clippers 203

The Dissipating Cyclone 204

Continental Cyclones and Global Climate Change 204

Summary 205

Test Your Understanding 206

Test Your Problem-Solving Skills 207

Chapter 11

Extratropical Cyclones Forming along the East and Gulf Coasts 209

Key Words 209

East Coast Cyclones 212

The Environment Before the Development of an East Coast Cyclone 212

The Initial Development of the Cyclone 214

STORMS AND SOCIETY Beach Erosion 215

FUN FACT Bomb Cyclones 216

Fronts, Airflow, and Weather Conditions 216

STORMS AND SOCIETY The Blizzard of 1888 217

Storm Evolution 218

FUN FACT Snowmageddon: Back to Back Nor’easters! 218

Gulf Coast Cyclones 220

The East Coast Storm Track 220

The Mississippi—Ohio River Valley Storm Track 222

Forecasting and Assessing the Impact of Coastal Cyclones 223

Coastal Cyclones and Global Climate Change 225

Test Your Understanding 226

Test Your Problem-Solving Skills 228

Chapter 12

Freezing Precipitation and Ice Storms 231

Key Words 231

Supercooled Water 232

Vertical Structure of the Atmosphere During Freezing Precipitation 233

Freezing Rain 233

Freezing Drizzle 235

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STORMS AND SOCIETY The Roselawn, Indiana, ATR72 Aircraft Accident and Freezing Drizzle Aloft 236

Weather Patterns Associated with Freezing Precipitation 236

FUN FACT Wind and Ice Storms 238

FUN FACT Warm Air Aloft! 238

EXTREME EVENT The 1998 Northeast Ice Storm 240

Forecasting Freezing Precipitation 241

Distribution of Freezing Precipitation in North America 241

Freezing Precipitation and Global Climate Change 243

Test Your Understanding 244

Test Your Problem-Solving Skills 245

Chapter 13

Lake-Effect Snowstorms 247Key Words 247

The Large-scale Weather Pattern for Lake-effect Snowstorms 249

Lake-effect Snowstorm Development 249

Climatology of Lake-effect Snows 251

Organization of Lake-effect Snowfall 255

Wind-parallel Rolls 255

Shore-parallel Bands 255

FUN FACT A Forecaster’s Nightmare 257

Vortices 257

EXTREME EVENTS Buffalo Snows of November 2014 258

Lake-enhanced Snowfall 259

Lake-effect Snow and Global Climate Change 260

Test Your Understanding 261

Test Your Problem-Solving Skills 262

Chapter 14

Cold Waves 263Key Words 263

Formation of Cold Airmasses 265

FUN FACT Extreme Cold in the Arctic 265

Outbreaks of Cold Air into Middle Latitudes of North America 267

EXTREME EVENT Bitter Cold in the Winters of 2014 and 2015 270

ADVANCED TOPIC Snow Cover: Nature’s Refrigerator 273

FUN FACT A Generational perspective on Cold Waves 275

Extreme Cold in Europe and Asia 275

Wind Chill 279

EXTREME EVENT The Greatest Arctic Outbreak in the United States: February 1899 281

Cold Waves and Global Climate Change 282

Test Your Understanding 283

Test Your Problem-Solving Skills 283

Chapter 15

Great Plains Blizzards 285Key Words 285

STORMS AND SOCIETY Hypothermia, frostbite, and blizzards 287

Cold, Wind, and Snow 287

Colorado Cyclones and Blizzards 289

EXTREME EVENT The Winter of Blizzards 291

FUN FACT Snow rollers 292

Alberta Clippers and Blizzards 293

Ground Blizzards 294

Blizzard Safety 294

Forecasting Blizzards 295

EXTREME EVENT The Children’s Blizzard of 1888 296

EXTREME EVENT The Great Chicago Blizzard of 2011 296

Blizzards and Global Climate Change 298

Test Your Understanding 298

Test Your Problem-Solving Skills 299

Chapter 16

Mountain Snowstorms 301Key Words 301

FUN FACT Avalanche! 303

SCIENCE AND TECHNOLOGY Cloud Seeding 304

Source of Mountain Snowstorms 306

Storms Along the Western Slopes of the United States 309

FUN FACT The Chain Law 310

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Storms on the East Slope of the Rockies 311

Global Climate Change: Mountain Snows and Dwindling Water Supplies 314

Test Your Understanding 316

Test Your Problem-Solving Skills 317

Chapter 17

Mountain Windstorms 319Key Words 319

The Dynamics of Downslope Windstorms 321

SCIENCE AND TECHNOLOGY T-REX and the Hunt for Rotors 323

Chinook Windstorms of the Rocky Mountains 325

FUN FACT Rapid Temperature Fluctuations 326

Forecasting Chinooks 327

Santa Ana Windstorms of California 329

Katabatic Winds 332

FUN FACT Katabatic Winds in North America 333

Mountain Windstorms and Global Climate Change 333

Test Your Understanding 334

Test Your Problem-Solving Skills 335

Chapter 18

Thunderstorms 337Key Words 337

Ordinary Thunderstorms 340

FUN FACT How Much Water Is in a Thunderstorm? 342

Mesoscale Convective Systems 343

SCIENCE AND TECHNOLOGY Nocturnal Thunderstorms and Plains Elevated Convection at Night 347

Frontal Squall Lines 350

Supercell Thunderstorms 353

FUN FACT Low Precipitation and High Precipitation Supercells 359

Thunderstorms and Global Climate Change 361

Test Your Understanding 363

Test Your Problem-Solving Skills 364

Chapter 19

Tornadoes 367Key Words 367

Tornado Formation in Supercells 369

SCIENCE AND TECHNOLOGY VORTEX 372

ADVANCED TOPIC Tornado Winds 378

EXTREME EVENT The Tri-State Tornado of 1925 381

EXTREME EVENT The Tornado Outbreak of 27 April 2011 in the Southeast United States 381

Tornado Formation within Nonsupercell Thunderstorms 382

FUN FACTS Other Tornado-Like Vortices 384

Tornado Statistics 385

Tornado Detection 391

Tornado Forecasting 393

Tornado Safety 394

Test Your Understanding 395

Test Your Problem-Solving Skills 396

Chapter 20

Hailstorms 399Key Words 398

FUN FACT How Big is a Hailstone? 402

Hail Embryo Formation 404

Hailstone Growth 404

EXTREME EVENT San Antonio’s Billion-dollar Hailstorm of April 2016 405

Forecasting and Detection of Hail 408

FUN FACTS Hail and “Green” Thunderstorms 408

SCIENCE AND TECHNOLOGY Radar Polarization 410

Distribution and Impacts of Hail 411

SCIENCE AND TECHNOLOGY Hail Suppression—Can Hail Damage Be Reduced? 415

Test Your Understanding 416

Test Your Problem-Solving Skills 416

Chapter 21

Lightning 419Key Words 419

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EXTREME EVENT Lightning and Forest Fires 422

The Lightning Stroke 423

Electricity and Charge 423

Charge Distribution and Charging Mechanisms in Thunderstorms 424

Interface charging 424

Induction charging 425

The Lightning Stroke 427

FUN FACT Lightning in Hurricanes 428

Other Phenomena Associated with Electrical Discharges in the Atmosphere 430

FUN FACT Ball Lightning 431

Lightning Safety 434

Test Your Understanding 434

Test Your Problem-Solving Skills 435

Chapter 22

Downbursts 437Key Words 437

Downburst Formation 438

Environmental Conditions Associated with Microburst Development 440

Downburst Structure 441

Types of Microbursts 444

FUN FACT How Common are Microbursts? 445

FUN FACT Heatbursts: Warm Blasts from Downdrafts 447

The Problem for Aircraft 448

EXTREME EVENT The John F. Kennedy International Airport Crash of Eastern Airlines Flight 66 450

EXTREME EVENT The Andrews Air Force Base Microburst of 1983 451

Modern Technology to Detect Microbursts 452

Prediction of Conditions Favorable for Microbursts 454

Test Your Understanding 455

Test Your Problem-Solving Skills 456

Chapter 23

El Niño, La Niña, and the Southern Oscillation 459

Key Words 459

The Southern Oscillation 461

Evolution of an ENSO Event 463

Consequences of El Niño 464

ADVANCED TOPIC ENSO and Hurricane Activity 466

EXTREME EVENTS El Niño and “Snowmageddon” in the Winter of 2009–2010 467

The La Niña Phase of the Southern Oscillation 469

Monitoring the Southern Oscillation 470

ADVANCED TOPIC The Strange El Niño of 2015–2016 470

El Niño and Global Warming 471

SCIENCE AND TECHNOLOGY Monitoring the Tropical Pacific Ocean 472

Test Your Understanding 474

Test Your Problem-Solving Skills 475

Chapter 24

Tropical Cyclones 479Key Words 479

EXTREME EVENTS Hurricanes Katrina (2005) and Sandy (2012)—Two Strikes on Our Vulnerable Coastal Cities 484

EXTREME EVENT The Record Setting Hurricane Season of 2005 486

Worldwide Hurricane Occurrences 488

Hurricane Tracks 489

Hurricane Structure 490

Tropical Cyclone Formation and Intensification 496

Trigger Mechanisms for Thunderstorms in the Tropics 496

The Environment Required for Tropical Cyclones to Form from Thunderstorm Clusters 500

How Thunderstorms Organize into a Hurricane 502

Destructive Forces in a Hurricane 508

Storm Surge 508

Other Disastrous Forces in Hurricanes 509

Forecasting Hurricane Tracks and Intensity 511

SCIENCE AND TECHNOLOGY Hurricane Research 511

Global Climate Change: Potential Effects on Hurricanes 514

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Test Your Understanding 515

Test Your Problem-Solving Skills 516

Chapter 25

Floods 519Key Words 519

EXTREME EVENTS Worldwide Floods 521

Types of Floods 523

FUN FACT Watersheds, River Stages, and Floodplains 524

North American Flood Weather Patterns 525

Flooding Following Landfall of Tropical Cyclones 525

Flooding from Other Tropical Weather Systems 526

Flooding from Mesoscale Convective Systems 527

EXTREME EVENTS Mississippi River Floods 529

Flooding from Frontal Overrunning 533

Flooding Compounded by Snowmelt 534

Flash Floods of the Desert Southwest 535

Flash Floods Along the East Slope of the Rocky Mountains 536

West Coast floods 540

Flood Forecasting and Safety 542

STORMS AND SOCIETY The Cleanup—Who’s Responsible? 544

Global Climate Change: Potential Effects on Floods 544

Test Your Understanding 546

Test Your Problem-Solving Skills 547

Chapter 26

Drought 549Key Words 549

EXTREME EVENTS Drought Disasters Occur Worldwide 550

Indices of Drought 552

Causes of Drought 553

Drought in the Central United States 554

The Drought of the Early 2010s 557

The Drought of 1988 559

FUN FACT Hotter Days and Cooler Nights during a Drought 559

The Drought of the 1930s: The Dust Bowl 561

STORMS AND SOCIETY Drought and Population Migration in the United States 562

Drought in the Eastern United States 563

Drought in the Western United States 565

SCIENCE AND TECHNOLOGY New Methods for Monitoring Drought 570

Historical Perspective on Drought 570

FUN FACT River Flows and Water Rights in the West 571

Global Climate Change: Potential Effects on Drought 572

Test Your Understanding 573

Test Your Problem-Solving Skills 574

Chapter 27

Heat Waves 577Key Words 577

EXTREME EVENT Recent Heat Waves around the World 578

Measures of Heat Stress 578

EXTREME EVENT How High Can the Heat Index Go? 581

Meteorological Conditions Associated with Heat Waves 582

WEATHER AND SOCIETY Heat Disorders and Safety Tips 583

Urban Heat Island Effect 586

Memorable Heat Waves in the United States 587

Heat Waves of 2012: Record-Setting Spring and Summer Temperatures 587

The July 1995 Heat Wave: Chicago and the Midwest 590

Heat Waves of the 1930s 593

FUN FACT The 1930s and the Advent of Air-Conditioning 595

Global Climate Change: Potential Effects on Heat Waves 595

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EXTREME EVENT The Russian Heat Wave of 2010 597

Test Your Understanding 598

Test Your Problem-Solving Skills 599

Appendix A Units, Conversions, and Constants 601

Appendix B Blank Maps and Charts 604

Appendix C Geography Overview 608

Appendix D Watches, Warnings, and Advisories for Severe and Hazardous Weather 610

Glossary 613

Index 635

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