The Tornado: Its Structure, Dynamics, Prediction, and Hazards

Geophysical Monograph Series......Page 1
The Tornado: Its Structure, Dynamics, Prediction, and Hazards......Page 5
CONTENTS......Page 7
Preface......Page 11
PHOTOGRAPHIC EVIDENCE OF THE STORM......Page 12
F5 PLAINFIELD TORNADO......Page 13
Do TORNADOES GROW UPWARD OR DOWNWARD?......Page 14
CLOUD-TOP FEATURES BY SATELLITES......Page 16
REFERENCES......Page 28
1. INTRODUCTION......Page 29
2. CORE FLOW, REGION I......Page 30
2.1. Dimensionless Parameters......Page 31
2.2. Simple Models......Page 32
2.3. Stability Considerations......Page 33
3. SURFACE BOUNDARY LAYER, REGION II......Page 34
4. UPPER FLOW, REGION IV......Page 35
5. CORNER FLOW, REGION III......Page 36
5.2. Influence of Turbulence......Page 39
6. ESTIMATES OF MAXIMUM VELOCITY......Page 40
7. LARGE-EDDY SIMULATION TORNADO MODEL......Page 43
REFERENCES......Page 45
2. THE MODEL......Page 50
3.1. No Rotation......Page 53
Lower Boundary......Page 54
Lower Boundary......Page 55
4. IMPLICATIONS FOR TORNADOES......Page 56
REFERENCES......Page 57
2.2. Numerical Model......Page 58
3. RESULTS......Page 59
4. SUMMARV......Page 62
REFERENCES......Page 63
PAPER A4......Page 64
PAPER A5......Page 65
2.2. Discovery of the Supercell......Page 66
2.3.Early Doppler Rader Investigations and Three- Dimensional Cloud Models......Page 67
2.4. Discovery of the Numerical-Model-Equivalent Supercell......Page 68
3.1. Midlevel Rotation......Page 73
4. CYCLONIC BIAS AND PROPAGATION......Page 75
5. ENERGETICS......Page 78
6. WHERE THE TORNADO FITS IN.........Page 80
REFERENCES......Page 81
1. INTRODUCTION......Page 83
2.2. Adaptive Grid Methodology......Page 84
3.1. Coarse-Resolution Simulation  Supercell Simulation......Page 85
3.2. Fine-Resolution simulation Tornado Cyclone Simulation......Page 86
3.3. Surface-Friction Simulation Tornado Run......Page 91
4. SUMMARY......Page 95
REFERENCES......Page 96
1. INTRODUCTION......Page 97
2. RESULTS......Page 98
3. VORTEX-LINE ANALYSIS......Page 101
4. CIRCULATION ANALYSIS......Page 102
REFERENCES......Page 103
1. INTRODUCTION......Page 104
3. RESULTS......Page 105
4. SUMMARY AND IMPLICATIONS......Page 109
REFERENCES......Page 110
2. THE INITIAL MIDLEVEL MESOCYCLONE......Page 112
4. THE DEVELOPMENT OF ROTATION NEXT TO THE GROUND......Page 114
5. CIRCULATION ANALYSIS......Page 115
6.VORTICITY CHANCES IN INDIVIDUAL PARCELS......Page 117
7. TORNADOGENESIS......Page 118
8. CONCLUSIONS......Page 120
REFERENCES......Page 121
PAPER B2......Page 122
PAPER B4......Page 123
PAPER B5......Page 124
1. INTRODUCTION......Page 125
2.1. Background......Page 126
2.2. Hurricane-Relative Spatial Distributions of Raob Parameters......Page 129
2.3. Correlations of Raob Parameters With Tornado Outbreak Intensity......Page 130
2.4. Proximity Composite Soundings......Page 131
2.5. Variations With Hurricane Intensity and Size......Page 135
2.6. Azimuthal Variations Around the Hurricanes......Page 136
3.1. Simulation Specifications......Page 138
3.2. Simulation of Hurricane Danny's Storms......Page 139
3.3. Simulation of "Close Proximity" Hurricane-Spawned Storms......Page 143
4. DISCUSSION......Page 144
REFERENCES......Page 147
2. LIFE CYCLE OF SUPERCELL STORMS......Page 149
2.2. Mature Stage......Page 150
2.3. Tornadic Stage......Page 153
2.4. Posttornadic Stage......Page 157
2.5. Summary......Page 158
3. NONSUPERcELL TORNADOES......Page 159
4. SUMMARY AND RECOMMENDATIONS......Page 163
REFERENCES......Page 164
1. INTRODUCTION......Page 166
2.1. The Supercell Sperctrum......Page 167
2.2. Hybrid Events......Page 168
2.3. Supercell Identification Criteria......Page 169
2.4. Tornadoes Within Supercells......Page 171
3.1. Landspouts......Page 172
3.4. Fair Weather Vortices......Page 173
4. CLASSIFICATION OF VORTICES......Page 174
5. DISCUSSION......Page 175
REFERENCES......Page 176
2. LIGHTNING TERMINOLOGY......Page 178
3. SFERICS STUDIES......Page 179
4. LIGHTNING MAPPING STUDIES......Page 180
5. POSITIVE CLOUD-TO-GROUND LIGHTNING IN TORNADIC STORMS......Page 184
6. CONCLUSION......Page 185
REFERENCES......Page 186
2. ENVIRONMENTAL SETTING......Page 188
3. STORM SYSTEM MORPHOLOGY......Page 189
3.2. Mature Phase of the Squall Line......Page 190
3.3. The Tornadic Supercell Storm......Page 194
4.1. Characteristics of the Tornado......Page 196
4.2. Mesoscale Analysis: General Patterns......Page 200
4.3. Surface Features and Timing of the Merger......Page 202
6. DISCUSSION AND SUMMARY......Page 203
REFERENCES......Page 204
PAPER C 1......Page 205
PAPER C5......Page 206
2. LIMITATIONS OF DOPPLER WEATHER RADAR......Page 207
2.2. Aspect Ratio Problems......Page 210
3.1. Tornadic Vortex Signatures......Page 211
3.2. Mesocyclone Signatures......Page 212
3.3. Misocyclone Signatures......Page 216
3.5. Estimated Skill......Page 218
4.1. Mesocyclone Algorithtns......Page 221
4.3. Tornado Prediction Algorithms......Page 222
5. FUTURE DIRECTIONS......Page 223
REFERENCES......Page 224
3. OBSERVATIONS......Page 226
3.1. Gustnadoes......Page 227
3.3. Brief-Supercell Tornadoes......Page 228
3.4. Long-Lived Supercell Tornadoes......Page 230
4. IMPACT ON TVS DETECTION ALGORI FHMS......Page 231
REFERENCES......Page 234
1. INTRODUCTION......Page 235
4. EXAMPLES OF THE FORECAST FEEDBACK PROCESS......Page 236
4.1. September 17, 1988, FO Tornado......Page 237
4.2. May 3I, 1985, F2-F4 Tornadoes......Page 238
6. CONCLUSION......Page 241
REFERENCES......Page 242
2. PRESENT KNOWLEDGE......Page 243
3. RADAR ECHO PATTERNS IDENTIFIED ON JUNE 2, 1990: ILLUSTRATIONS OF CLASSIC AND HP SuPoeRCELt. S......Page 245
4. NEW CONCEPTUAL HP STORM MODELS......Page 250
5. SUMMARY......Page 251
REFERENCES......Page 252
2. PROPOSED MECHANISM FOR MESOCYCLONE INITIATION......Page 253
3.1. Agawam, Oklahoma, Hailstorm of June 6, 1979......Page 254
3.2. Billings and Guthrie, Oklahoma, Stormsof April 26, 1984......Page 255
4. CONCLUDING DISCUSSION......Page 256
REFERENCES......Page 257
1. INTRODUCTION......Page 258
3. THE SUPERCELL EVOLUTION......Page 259
4. CONCLUSIONS......Page 263
REFERENCES......Page 264
2.1. Moisture and Water Vapor Data......Page 266
2.3. Image Interpretation: Daytime Squall Line Development......Page 267
2.4. Image Interpretation: Nighttime Squall Line Development......Page 268
2.5. Image Interpretation: Mesoscale Convective Complexes......Page 269
3.1. Isolation of Preferred Areas for Tornadic Storm Development: Interaction With Boundaries......Page 270
3.2. Satellite Observations of SupercelIs......Page 272
3.3. A Conceptual Model of Tornadic Storms......Page 273
REFERENCES......Page 274
PAPER D2......Page 276
PAPER D6......Page 277
2. TORNADO VORTEX SIMULATION......Page 278
2.2. Current Status of Working TVCs......Page 279
2.3. Practical Aspects......Page 281
3.1. Visual Observations......Page 283
3.2. Velocity Fields......Page 285
3.3. Pressure Fields......Page 287
3.4. Surface Roughness......Page 290
4. SUMMARY AND SUGGESTIONS FOR FUTURE WORK......Page 294
REFERENCES......Page 295
3.1. Configuration of the Apparatus......Page 297
3.2. Radial Profiles of Velocity Components......Page 298
3.3. Vertical Profileso f VelocityC omponentsin the Outer Flow......Page 300
4. ASSESSMENT OF THE IMPACT OF VORTEX WANDER......Page 302
5. SUMMARY AND CONCLUSIONS......Page 304
REFERENCES......Page 306
2. METHODOLOGY......Page 307
3. RESULTS......Page 309
4. DISCUSSION......Page 312
REFERENCES......Page 316
PAPER E2......Page 317
PAPER E3......Page 318
2.1. NSSL Tornado Intercept Project......Page 319
2.2. Tornadoes and Rough Terrain......Page 320
2.3. A Conceptual Model Jbr Great Plains Supercell Tornadoes......Page 321
3.1. The Waterspout Life Cycle......Page 322
3.2. Waterspout Linkages to Tornadoes......Page 324
4.1. Flow Asymmetries......Page 326
5. WIND ESTIMATES FROM TORNADO DAMAGE SURVEYS......Page 328
6.2. TOTO......Page 330
6.3. Turtles......Page 331
6.4. Portable Rawinsondes......Page 332
7. DOPPLER RADAR MEASUREMENTS......Page 333
7.2. Fixed-Site Doppler Radar Observations of Nonsupercell Tornadoes......Page 334
7.3. Portable Doppler Radar Observations of Supercell Tornadoes......Page 336
8.4. Portable and Airborne Doppler Lidar......Page 338
9. SUMMARY......Page 346
REFFRENCE3......Page 349
2. REVIEW OF COLORADOT ORNADOO BSERVATIONASN D RESEARCH DURING THE PAST DECADE......Page 353
Visual Observations......Page 356
Overview of Conditions......Page 357
Detailed Surface Observations......Page 360
4. SUMMARY AND CONCLUSIONS......Page 363
REFERENCES......Page 366
2. PRINCIPLES OF FM-CW DOPPLER RADAR......Page 367
4. DESIGN OF THE Los ALAMOS NATIONAL LABOIL&TORY PORTABLE RADAR......Page 369
6. PRELIMINARY RESULTS......Page 372
7. SUGGESTED FUTURE IMPROVEMENTS......Page 374
REFERENCES......Page 376
PAPER F3......Page 377
PAPER F4......Page 378
2. PERFORMANCE GOALS......Page 379
4. DESIGN AND EVALUATION CRITERIA FOR WIND LOAD......Page 380
Establishment of Wind and Tornado Hazard Annual Probabilities......Page 381
General Use Facilities......Page 382
Moderate Hazard Facilities......Page 383
High-Hazard Facilities......Page 385
Comments on Load Combinations......Page 386
REFERENCES......Page 387
CURRENT NRC REQUIREMENT......Page 388
TORNADO MISSILE RISK......Page 390
EXTREME WIND RISK......Page 391
INDIVIDUAL PLANT EXAMINATION OF EXTERNAL. EVENTS......Page 394
REFERENCES......Page 395
3. DESIGN GUIDELINES DEVELOPMENT STRATEGY......Page 397
3.1. Developing Wind Load Specifications Based on Site-Specific Hazard Frequency Curves......Page 398
4.2. Missile Load Specification......Page 399
4.4. Risk Assessmenfto r Wind Speeds and Missile Criteria......Page 400
REFERENCES......Page 401
PAPER G2......Page 402
PAPER G5......Page 403
1.2. Probability Map Sets......Page 405
1.3. University of Chicago Model......Page 406
1.5. Texas Tech University......Page 409
1.6. Twisdale/Electric Power Research Institute......Page 412
1.7. Fujita-McDonald Comparison......Page 413
2.1. General Climatology......Page 414
2.2. The Annual Number of Tornadoes......Page 417
2.3. State CIimatologies......Page 418
3. THE FUTURE OF TORNADO CLIMATOLOGY AND RISK ASSESSMENT......Page 420
REFERENCES......Page 421
2.2. Diurnal and Seasonal Distributions......Page 423
2.3. Path Dimensions......Page 424
4. PARTICULAR FEATURES RELATED TO GROUND CONFIGURATION......Page 425
4.3. A Tornado Alley in the Jura Mountains?......Page 426
6. SUMMARY AND CONCLUSIONS......Page 428
REFERENCES......Page 429
2. GEOGRAPHICAL DISTRIBUTION AND CLIMATIC CHARACTERISTICS......Page 431
3.1. Middle and Lower Reaches of the Yangtze Valley......Page 433
4. VISUAL ASPECTS OF TORNADOES......Page 436
5. RADAR ASPECTS OF TORNADOES......Page 437
6. DISCUSSION......Page 438
REFERENCES......Page 440
2. DATA AND ANALYSES PROCEDURES......Page 441
3. GENERAL PATTERNS......Page 442
4. DIURNAL BEHAVIOR OF TORNADOES......Page 444
4.2. Spring Patterns......Page 445
5. SUMMARY......Page 446
REFERENCES......Page 448
3. TORNADO INTENSITY......Page 449
4. METEOROLOGICAFLA CTORS SYNOPTIC SCALE AND EXAMPLES......Page 450
Eugene, Oregon, Tornado, November 24, 1989......Page 451
Vancouver, Washington, Tornado, April 5, 1972......Page 452
REFERENCES......Page 453
2. TIME SER1ES ANALYSIS......Page 454
3. TIME DEPENDENCE OF SPATIAL DISTRIBUTION......Page 457
4. CONSISTENCY OF SPATIAL PATTERNS......Page 458
REFERENCES......Page 460
2. PRE-1915......Page 462
6. FUJITA SCALE STANDARDS......Page 464
8. KILLER TORNADOES AND DEATHS......Page 465
9. A TALE OF TWO CITIES......Page 467
10. RECOMMENDATIONS......Page 468
REFERENCES......Page 469
PAPER H1......Page 470
PAPER H4......Page 471
PAPER H7......Page 472
PAPER H8......Page 473
2. DETERMINATION OF MULTISCALE AIRFLOWS OF TORNADOES......Page 474
3. EVIDENCE OF SUCTION VORTICES......Page 476
4. MICROBURST, INDUCER OF NONTORNADIC DAMAGING WINDS......Page 477
6. TORNADO-M1CROBURISNTT ERACTION......Page 485
REFERENCES......Page 487
3. BUILDINGS DO Nox EXPLODE......Page 489
5. TYPICAL WOOD FRAME BUILDING FAILURES......Page 490
8. ROOF SYSTEM PROBLEMS......Page 491
REFERENCES......Page 492
3. MORPHOLOGY OF THE STORM......Page 494
4. DAMAGE SURVEY RESULTS......Page 495
REFERENCES......Page 503
1. INTRODUCTION......Page 504
2.3. Meteorological Records......Page 505
2.4. Tornado Path......Page 506
2.6. Translational Velocity......Page 508
3.3. Tornado Cyclone......Page 509
REFERENCES......Page 512
PAPER 12......Page 513
PAPER 15......Page 514
Tornado Shelters......Page 515
Protective Areas......Page 518
Reluctance to Invest in Tornado Protection......Page 519
CONCLUSIONS......Page 520
2. REVIEW OF LITERATURE......Page 521
4.1. Characteristics of Killer Tornadoes......Page 522
4.2. Age of Victims......Page 523
4.6. Cause of Death......Page 524
5. CONCLUSIONS AND RECOMMENDATIONS......Page 525
REFERENCES......Page 526
1. INTRODUCTION......Page 527
2.1. Wind Loading......Page 528
2.2. Building Response......Page 529
3.2. Equations for Calcldating Wind Speed From Damage......Page 530
3.3. Procedure and Example......Page 531
4. CONCLUDING REMARKS......Page 532
REFERENCES......Page 533
RESULTS......Page 534
REFERENCES......Page 535
RATIONALE FOR SCHOOL BOARDS......Page 536
BACKGROUND......Page 538
DESIGN CONSIDERATIONS......Page 539
EXAMPLES OF SCHOOLS INCORPORATING OCCUPANT PROTECTIVE AREAS......Page 543
REFERENCES......Page 544
PAPER J2......Page 545
PAPER J4......Page 546
2. SHORT HISTORY OF TORNADO FORECASTING......Page 547
3.1. Forecasting Procedures: Convective Outlooks......Page 551
3.2. Forecasting Procedures: Watches......Page 552
4. 35 YEARS OF TORNADO FORECAST VERIFICATION......Page 554
5. CURRENT UNDERSTANDING OF TORNADIC STORMS......Page 557
6. 1. Technological Tools......Page 558
6.2. Productive Areas for Research......Page 559
REFERENCES......Page 560
1. INTRODUCTION......Page 562
5. ESTIMATION OF STORM MOTION FOR STORM-RELATIVE HELICITY COMPUTATIONS......Page 563
6. STORM-RELATIVE HELlCITY RESULTS......Page 564
7. BULK RICHARDSON NUMBER SHEAR U RESULTS......Page 565
9. CASE STUDIES......Page 566
9.2. Central Kansas/Southeast Wyoming, May 24, 1990......Page 567
10. EXTREMES OF HODOGRAPHS ASSOCIATED WITH SUPERCELL-INDUCED TORNADOES......Page 568
1 I. DISCUSSION......Page 569
REFERENCES......Page 571
2.1. Calculation of CAPE......Page 572
3.1. Potential Buoyant Energy Distribution......Page 573
3.2. Bulk Richardson Numbers......Page 574
3.3. CAPE and O- 2-kin AGL Positive Wind Shear Relationship......Page 575
3.4. CAPE and Helicity Relationship......Page 576
4. DISCUSSION......Page 577
REFERENCES......Page 578
2. TYPICAL SUPERCELL ENVIRONMENTS......Page 580
3. THE NOCTURNAL JF, T AND STORM-RELATIVE HELlCITY......Page 583
REFERENCES......Page 586
2. ROLE OF BROADCAST METEOROLOGISTS IN PUBLIC EDUCATION......Page 588
3.1. The Anticipation Phase......Page 589
4. BROADCAST METEOROLOGISTS AND NWS......Page 590
6. CONCLUSION......Page 591
REFERENCES......Page 592
2. THE "SHORT FUSE" COMPOSITE......Page 593
3. RESULTS OF THE CASE STUDIES......Page 594
4. THREE SPECIFIC CASES......Page 595
REFERENCES......Page 598
2. DATA......Page 599
3. METEOROLOGICAL SETTING......Page 600
4. ANALYSIS......Page 602
5. DISCUSSION......Page 605
5.1. Characteristics of the Storm-Relative Environment......Page 607
5.2. CAPE and Storm-Relative Helicity......Page 609
5.3. The Supercell Environment......Page 610
5.4. Summary of the Plainfield Enviromnent......Page 611
REFERENCES......Page 612
2. METHODOLOGY OF CASE SELECTION......Page 613
3.3. Relative Attnospheric Profiles......Page 615
4. CONCLUDING REMARKS......Page 617
REFERENCES......Page 620
PAPER L2......Page 621
PAPER L3......Page 622
PRESENTATION 2......Page 623
PRESENTATION 3......Page 624
PRESENTATION 4......Page 625