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A Multiscale Analysis of A Multiscale Analysis of the 23-24 November 2004 the 23-24 November 2004 Southeast United States Southeast United States Tornado Outbreak Tornado Outbreak Alicia C. Wasula Alicia C. Wasula

A Multiscale Analysis of the 23-24 November 2004 Southeast United States Tornado Outbreak

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A Multiscale Analysis of the 23-24 November 2004 Southeast United States Tornado Outbreak. Alicia C. Wasula. Event Summary. 23/1700 UTC – 24/1300 UTC (nocturnal) 80 Tornadoes (17 F2 or greater) 3 Fatalities / 38 Injuries 45% tornadoes close to Gulf coast (south of 32 N). Motivation. - PowerPoint PPT Presentation

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Page 1: A Multiscale Analysis of the 23-24 November 2004 Southeast United States Tornado Outbreak

A Multiscale Analysis of the A Multiscale Analysis of the 23-24 November 2004 23-24 November 2004

Southeast United States Southeast United States Tornado OutbreakTornado Outbreak

Alicia C. WasulaAlicia C. Wasula

Page 2: A Multiscale Analysis of the 23-24 November 2004 Southeast United States Tornado Outbreak

Event SummaryEvent Summary

23/1700 UTC – 24/1300 UTC 23/1700 UTC – 24/1300 UTC (nocturnal)(nocturnal)

80 Tornadoes (17 F2 or greater)80 Tornadoes (17 F2 or greater) 3 Fatalities / 38 Injuries3 Fatalities / 38 Injuries 45% tornadoes close to Gulf coast 45% tornadoes close to Gulf coast

(south of 32 (south of 32 N)N)

Page 3: A Multiscale Analysis of the 23-24 November 2004 Southeast United States Tornado Outbreak
Page 4: A Multiscale Analysis of the 23-24 November 2004 Southeast United States Tornado Outbreak

MotivationMotivation

Examine tornado episode from Examine tornado episode from synoptic/mesoscale perspective to synoptic/mesoscale perspective to look for similarities/differences to look for similarities/differences to composite Gulf coast tornado composite Gulf coast tornado episodeepisode

Page 5: A Multiscale Analysis of the 23-24 November 2004 Southeast United States Tornado Outbreak

0-2

km

posi

tive m

ean

sh

ear

(x 1

00

-2 k

m p

osi

tive m

ean

sh

ear

(x 1

0 -3-3 s s -

-

11))Convective Available Potential Energy (CAPE, Convective Available Potential Energy (CAPE, J/kg)J/kg)

Johns et Johns et al. 1993al. 1993

CAPE vs. Shear for Cold Season Tornado CAPE vs. Shear for Cold Season Tornado CasesCases

Page 6: A Multiscale Analysis of the 23-24 November 2004 Southeast United States Tornado Outbreak

0-2

km

posi

tive m

ean

sh

ear

(x 1

00

-2 k

m p

osi

tive m

ean

sh

ear

(x 1

0 -3-3 s s -

-

11))Convective Available Potential Energy (CAPE, Convective Available Potential Energy (CAPE, J/kg)J/kg)

Johns et Johns et al. 1993al. 1993

CAPE vs. Shear for Warm Season Tornado CAPE vs. Shear for Warm Season Tornado CasesCases

Page 7: A Multiscale Analysis of the 23-24 November 2004 Southeast United States Tornado Outbreak

Tornado Episode Tornado Episode CompositesComposites

NCEP/NCAR 2.5NCEP/NCAR 2.5x 2.5x 2.5 Reanalysis Reanalysis datasetdataset

All tornado episodes 1950-2001All tornado episodes 1950-2001 ‘‘Episode-relative’ compositeEpisode-relative’ composite Grouped by start time: 0000-0600, Grouped by start time: 0000-0600,

0600-1200, 1200-1800, 1800-0000 0600-1200, 1200-1800, 1800-0000 UTCUTC

Will show 0600-1200 UTC onlyWill show 0600-1200 UTC only

Page 8: A Multiscale Analysis of the 23-24 November 2004 Southeast United States Tornado Outbreak

200 hPa height (m), isotachs (m s200 hPa height (m), isotachs (m s-1-1))

500 hPa hgt (m), avor. (x 10500 hPa hgt (m), avor. (x 10-5-5 s s-1-1), vort. adv. (x 10), vort. adv. (x 10-10-10 s s-2-2))

Page 9: A Multiscale Analysis of the 23-24 November 2004 Southeast United States Tornado Outbreak

850 hPa hgt (m), temp (850 hPa hgt (m), temp (C), temp. adv. (x 10C), temp. adv. (x 10-5-5 C sC s-1-1))

1000 hPa height (m), 1000-500 thck. (dam), 700 hPa RH (%)1000 hPa height (m), 1000-500 thck. (dam), 700 hPa RH (%)

Page 10: A Multiscale Analysis of the 23-24 November 2004 Southeast United States Tornado Outbreak

700 hPa height (m), vertical motion (x 10700 hPa height (m), vertical motion (x 10-3-3 hPa s hPa s-1-1))

850 hPa winds, 850 hPa winds, ee (K), 850-500 lapse rate ( (K), 850-500 lapse rate (C)C)

Page 11: A Multiscale Analysis of the 23-24 November 2004 Southeast United States Tornado Outbreak

Summary: CompositesSummary: Composites

Strong signal in spite of large sample size:Strong signal in spite of large sample size: ULJ entrance region at 200 hPaULJ entrance region at 200 hPa Vigorous upstream trough at 500 hPaVigorous upstream trough at 500 hPa Southwesterly LLJ at 850 hPaSouthwesterly LLJ at 850 hPa Low-level Low-level ee ridge ridge

Surface composites show 1Surface composites show 1stst tornado occurs: tornado occurs: At strongest At strongest TT On northern edge of moisture surge/southerly On northern edge of moisture surge/southerly

flowflow Dew point anomalies > +8 Dew point anomalies > +8 CC

Page 12: A Multiscale Analysis of the 23-24 November 2004 Southeast United States Tornado Outbreak

Case Study:Case Study:24 November 24 November

20042004

Page 13: A Multiscale Analysis of the 23-24 November 2004 Southeast United States Tornado Outbreak

http://www.spc.noaa.gov

Page 14: A Multiscale Analysis of the 23-24 November 2004 Southeast United States Tornado Outbreak
Page 15: A Multiscale Analysis of the 23-24 November 2004 Southeast United States Tornado Outbreak

22 November 2004 0000 UTC

SLP, 1000-500 THCK 500 hPa HGHT, AVOR

200 hPa HGHT, ISOTACHS 850 hPa HGHT, e, ISOTACHS

Page 16: A Multiscale Analysis of the 23-24 November 2004 Southeast United States Tornado Outbreak

22 November 2004 1200 UTC

SLP, 1000-500 THCK 500 hPa HGHT, AVOR

200 hPa HGHT, ISOTACHS 850 hPa HGHT, e, ISOTACHS

Page 17: A Multiscale Analysis of the 23-24 November 2004 Southeast United States Tornado Outbreak

23 November 2004 0000 UTC

SLP, 1000-500 THCK 500 hPa HGHT, AVOR

200 hPa HGHT, ISOTACHS 850 hPa HGHT, e, ISOTACHS

Page 18: A Multiscale Analysis of the 23-24 November 2004 Southeast United States Tornado Outbreak

23 November 2004 1200 UTC

SLP, 1000-500 THCK 500 hPa HGHT, AVOR

200 hPa HGHT, ISOTACHS 850 hPa HGHT, e, ISOTACHS

Page 19: A Multiscale Analysis of the 23-24 November 2004 Southeast United States Tornado Outbreak

23 November 2004 1800 UTC

SLP, 1000-500 THCK 500 hPa HGHT, AVOR

200 hPa HGHT, ISOTACHS 850 hPa HGHT, e, ISOTACHS

Page 20: A Multiscale Analysis of the 23-24 November 2004 Southeast United States Tornado Outbreak

24 November 2004 0000 UTC

SLP, 1000-500 THCK 500 hPa HGHT, AVOR

200 hPa HGHT, ISOTACHS 850 hPa HGHT, e, ISOTACHS

Page 21: A Multiscale Analysis of the 23-24 November 2004 Southeast United States Tornado Outbreak

24 November 2004 0600 UTC

SLP, 1000-500 THCK 500 hPa HGHT, AVOR

200 hPa HGHT, ISOTACHS 850 hPa HGHT, e, ISOTACHS

Page 22: A Multiscale Analysis of the 23-24 November 2004 Southeast United States Tornado Outbreak

24 November 2004 1200 UTC

SLP, 1000-500 THCK 500 hPa HGHT, AVOR

200 hPa HGHT, ISOTACHS 850 hPa HGHT, e, ISOTACHS

Page 23: A Multiscale Analysis of the 23-24 November 2004 Southeast United States Tornado Outbreak

CAPE 1847 J/kgLI -70-6 km shear 38 kt0-2 km shear 18 ktSWEAT 400

JAN23/2100 UTC

Page 24: A Multiscale Analysis of the 23-24 November 2004 Southeast United States Tornado Outbreak

CAPE 1648 J/kgLI -60-6 km shear 58 kt0-2 km shear 16 ktSWEAT 464

JAN24/0000 UTC

Page 25: A Multiscale Analysis of the 23-24 November 2004 Southeast United States Tornado Outbreak

CAPE 81 J/kgLI 30-6 km shear 39 kt0-2 km shear 22 ktSWEAT 225

JAN24/1200 UTC

Page 26: A Multiscale Analysis of the 23-24 November 2004 Southeast United States Tornado Outbreak

CAPE 1794 J/kgLI -60-6 km shear 54 kt0-2 km shear 4 ktSWEAT 279

LIX24/0000 UTC

Page 27: A Multiscale Analysis of the 23-24 November 2004 Southeast United States Tornado Outbreak

CAPE 2087 J/kgLI -70-6 km shear 40 kt0-2 km shear 12 ktSWEAT 332

LIX24/0600 UTC

Page 28: A Multiscale Analysis of the 23-24 November 2004 Southeast United States Tornado Outbreak

CAPE 2986 J/kgLI -100-6 km shear 32 kt0-2 km shear 10 ktSWEAT 513

LCH23/1800 UTC

Page 29: A Multiscale Analysis of the 23-24 November 2004 Southeast United States Tornado Outbreak

CAPE 2412 J/kgLI -80-6 km shear 42 kt0-2 km shear 9 ktSWEAT 353

LCH24/0000 UTC

Page 30: A Multiscale Analysis of the 23-24 November 2004 Southeast United States Tornado Outbreak

Surface Analysis24 November 20040000 UTC

Page 31: A Multiscale Analysis of the 23-24 November 2004 Southeast United States Tornado Outbreak

http://www.spc.noaa.gov

Page 32: A Multiscale Analysis of the 23-24 November 2004 Southeast United States Tornado Outbreak

http://www.spc.noaa.gov

Page 33: A Multiscale Analysis of the 23-24 November 2004 Southeast United States Tornado Outbreak

Surface Analysis24 November 20040600 UTC

Page 34: A Multiscale Analysis of the 23-24 November 2004 Southeast United States Tornado Outbreak

http://www.spc.noaa.gov

Page 35: A Multiscale Analysis of the 23-24 November 2004 Southeast United States Tornado Outbreak

                                                                                                                                        <>

IR24 November 20040615 UTC http://locust.mmm.ucar.edu

Page 36: A Multiscale Analysis of the 23-24 November 2004 Southeast United States Tornado Outbreak

http://www.spc.noaa.gov

Page 37: A Multiscale Analysis of the 23-24 November 2004 Southeast United States Tornado Outbreak

Surface Analysis24 November 20041200 UTC

Page 38: A Multiscale Analysis of the 23-24 November 2004 Southeast United States Tornado Outbreak

http://www.spc.noaa.gov

Page 39: A Multiscale Analysis of the 23-24 November 2004 Southeast United States Tornado Outbreak
Page 40: A Multiscale Analysis of the 23-24 November 2004 Southeast United States Tornado Outbreak

ConclusionsConclusions

Tornado episode occurred:Tornado episode occurred: In presence of strong synoptic-scale In presence of strong synoptic-scale

forcing for ascent (in warm sector)forcing for ascent (in warm sector) LLJ strength increased overnightLLJ strength increased overnight Surface winds stayed south or southeast Surface winds stayed south or southeast

as surface low rapidly deepened to the as surface low rapidly deepened to the northnorth

Ample moisture and instabilityAmple moisture and instability

Page 41: A Multiscale Analysis of the 23-24 November 2004 Southeast United States Tornado Outbreak

ConclusionsConclusions

Case study shows similarities to composite Case study shows similarities to composite tornado episodetornado episode Strong shear/ULJ/LLJStrong shear/ULJ/LLJ Deepening surface cycloneDeepening surface cyclone Ample low-level moisture (esp. close to coast)Ample low-level moisture (esp. close to coast) Surface winds ‘back’ with time ahead of Surface winds ‘back’ with time ahead of

surface lowsurface low Difference:Difference:

Mesoscale thermal gradient?Mesoscale thermal gradient?

Page 42: A Multiscale Analysis of the 23-24 November 2004 Southeast United States Tornado Outbreak

Future WorkFuture Work

Question:Question: Did isallobaric effects help to keep flow Did isallobaric effects help to keep flow

in warm sector southerly/southeasterly in warm sector southerly/southeasterly and allow warm moist Gulf air to remain and allow warm moist Gulf air to remain in place close to coast?in place close to coast?

Why did LLJ increase in strength so Why did LLJ increase in strength so rapidly?rapidly? Dynamically driven?Dynamically driven?