7 January 2008 Tornadoat the Rolla-Vichy National Airport

John GaganNOAA • National Weather Service

Springfield, Missouri

Outline

• Event overview• Focus on tornadic supercell affecting KVIH

– Reflectivity, SRM and Base Velocity Imagery– Warning decision process– Role of Heuristics (“gut feelings”)

• KVIH observations (1 min, 5 sec) – direct hit!• Pics from Survey

Event Overview

• 12 hours of tornadoes, hail, wind and flooding• Watches: 3 Tornado Watches (1 PDS), 1 Severe• Warnings: 62 Tornado, 33 Severe, 4 Flash Flood• 161 Severe Weather Reports• 33 Tornadoes• 3 Fatalities, Numerous Injuries• In previous Januaries from 1950-2007, only 5

Tornadoes were reported in SW Missouri

Event Overview

Event Overview250 mb

00z January 8th

Event Overview500 mb

00z January 8th

Event Overview850 mb

00z January 8th

SGF

RAO

B00

z Jan

uary

8th

Loop of Event

33 Tornadoes in January!

Only 5 tornadoes reported in January from 1950-2007!

LSX

SGF

• KLSX WSR 88D• KVIH is ~5200 ft AGL• Rank 5-6 Meso

• non continuous• No TVS• Warning decision

~0325 UTC

From IEM COW – Iowa State University

Warning Decision

• Quickly transitioned from coordinator role to warning operator– Bathroom breaks!!!!– Warning operator fatigue

• Assigned to Sector 3 (central MO)• Meso was weakening• No recent (<30 min) reports from the storm• Why continue to warn?

Warning Decision• Ultimately, the warning decision hinged on a

heuristic (gut feeling)– Meso began to reorganize/strengthen– Reflectivity structure in tact– Not much info < 8000 ft– Past history – numerous reports of damage – cyclic

• “Warn on a cyclic supercell until it’s someone else’s problem.”

• Great reference– “Gut Feelings: The Intelligence of the Unconscious”– Gerd Gigerenzer

KVIHVichy Tornado Track

340

341

342

343

344

345

346

347

348

349

350

351

352

353

354

355

356

357

358

359

400

401

402

403

404

405

406

407

408

409

4100

10

20

30

40

50

60

70

80

90

10 9 8 7 6 64 5 6

811 12 13

16 17

27

4442

29

2117 16 15

1210 11 11

9 8 7 7

12 11 118 7 7 7 8

1113

1714

18

2422

67

84

48

30

2219 19 19

14 13 1412 12

9 911

KVIH Station 2-min and 5-sec Wind Speed Plot340 to 410 UTC 8 January 2008

2min Wind Spd 5sec Wind Spd

Hour UTC

Knot

s

2 Minute Wind 5 Second Wind

KVIH Takes a Direct Hit!

0347 UTCTo

0400 UTC

• Wind direction switched from ESE to WNW

• Wind speed changed from 5 to 44 knots

• Wind direction switched from ESE to NW

• Wind speed changed from 8 to 84 knots

KVIHDouglas DC-3WWII Era Planes

KVIH

EF Rating

• Main casualty was trees– A few hard and soft wood trees uprooted– DIs 27 and 28, highest DOD was 3

• Most extensive damage was to the destroyed mobile home– Not tied down well – Pushed and rolled– Debris field scattered over 200 yds– DI 3 (single wide), DOD 9 (lower bound)– Damage consistent with high end EF-1

• VIH ASOS ~ 1-1.5 mi west of mobile home damage– 5 second wind speed well within EF-1 range

• 13 mile path, max width 100 yds, max winds 110 mph

Acknowledgements

• Ron Przybylinski – LSX radar• Kelsey Angle – Prior work on event• The SGF office for a job well done

Thank You

John.Gagan@noaa.gov