# Presentation: 369419

## Tropical Cyclone Tornadoes

- Eugene W. McCaul, Jr.
- USRA Huntsville
- NSSTC/GHCC/SPoRT

## 2004-2005 TC Tornadoes Smash All Previous Records

- CONUS hit by 15 tornadic TCs in 2004-5
- 2004 TC tornado count = 339, far larger than any other year (~15x normal)
- 2005 TC tornado count is 224, ~10x normal
- 2004-5 count alone almost = the full count in McCaul’s (1991) 39-yr climatology!
- For full details, see Grazulis website:
- _[www.tornadoproject.com/alltorns/tcyclone1.html](http://www.tornadoproject.com/alltorns/tcyclone1.html)_
- _[www.tornadoproject.com/alltorns/tcyclone2.html](http://www.tornadoproject.com/alltorns/tcyclone2.html)_

## 2004 TC Tornado Counts

| TC names | Dates | States | Number | Killers | Deaths |
| --- | --- | --- | --- | --- | --- |
| Bonnie | 12 Aug | FL,GA,SC
NC,VA | 18 | 1 | 3 |
| Charley | 12-14 Aug | FL,SC,NC
VA | 25 | 0 | 0 |
| Gaston | 29-30 Aug | SC,NC,VA | 20 | 0 | 0 |
| Frances | 4-8 Sep | FL,GA,SC
NC,VA | 106 | 0 | 0 |
| Ivan | 15-19 Sep | FL,GA,SC,
NC,VA,PA
MD,WV | 127 | 4 | 7 |
| Jeanne | 26-28 Sep | FL,GA,SC,
NC,VA | 42 | 1 | 1
 |
| Matthew | 9 Oct | LA | 1 | 0 | 0
 |

## 2005 TC Tornado Counts

| TC names | Dates | States | Number | Killers | Deaths |
| --- | --- | --- | --- | --- | --- |
| Arlene | 11 Jun | FL,IN | 3 | 0 | 0 |
| Cindy | 6 Jul | FL,SC,NC,
AL,GAVA | 44 | 0 | 0 |
| Dennis | 9 Jul | FL | 9 | 0 | 0 |
| Emily | 20 Jul | TX | 11 | 0 | 0 |
| Katrina | 26-31 Aug | FL,GA,ALMS,NC,PA
VA,OH | 58 | 1 | 1 |
| Rita | 23-26 Sep | LA,AR,MS
AL,FL | 92 | 1 | 1
 |
| Tammy | 5 Oct | GA | 1 | 0 | 0 |
| Wilma | 23 Oct | FL | 8 | 0 | 0 |

## TC tornado outbreaks: number

- Both Frances (106) and Ivan (127) spawned more than 100 tornadoes; the first TCs to do so in 37 years; Rita came close with 92
- 1967’s Beulah (115) relinquishes champ spot to Ivan (127)
- 3 of all-time top 4 outbreaks, and 6 of top 10, occurred in 2004-5
- In the top 25 outbreaks, only 2004 and 2005 are represented with multiple storms

## Top 10 TC Tornado Outbreaks

| H Ivan | 2004 | 127 |
| --- | --- | --- |
| H Beulah | 1967 | 115 |
| H Frances | 2004 | 106 |
| H Rita | 2005 |   92 |
| H Andrew | 1992 |   61 |
| H Katrina | 2005 |   58 |
| H Georges | 1998 |   48 |
| H Gilbert | 1988 |   47 |
| H Cindy | 2005 |   44 |
| H Jeanne | 2004 |   42 |

## TC tornado outbreaks: severity

- Frances, Ivan, Rita spawned some F3s
- 8 killer tornadoes overall from TCs in 2004-5
- 4 killer tornadoes from one TC, Ivan (first time since 1891, according to Grazulis)
- One of Ivan’s tornadoes killed 4; largest TC tornado death toll since 1972
- Through 30 Sep 2004, 6 of 14 CONUS killer tornadoes in 2004 were from TCs; 11 of 27 deaths; 7 deaths occurred from nocturnal tornadoes (Bonnie, Ivan)

## TC tornado outbreaks: character

- 2004-5 TC tornado events “well-behaved”
- Tended to form in NE or RF quadrants following TC recurvature
- Tended to form in large, intense TCs
- Tended to form in TCs moving 4-8 m/s at landfall
- Tended to form in weak baroclinic zones (old fronts, cool wedges, coastal fronts, etc)

## TC tornado outbreaks: areas

- Most tornadic TCs made landfall on Gulf coast, (except Frances, Jeanne, Gaston, Tammy)
- TC tracks in 2004 were channeled inland up the Appalachians or Atlantic coast by persistent synoptic-scale trough pattern
- All 2004 TC tornadoes were confined to FL,GA, SC,NC,VA,MD,WV,PA; 2005 more widespread
- Large tornado swarms occurred in SC (Frances); nw FL (Ivan), and VA-MD (Ivan); AL-GA (Cindy); AL-GA (Katrina); MS-AL (Rita)

## TC tornado outbreaks: records

- Several states established new maximum annual tornado counts because of TCs:
- SC annual record now 82 (was 54)
- VA annual record now 86 (was 32)
- MS annual record now 99 (was 64)
- AL annual record now 77 (was 55)
- Both SC and VA now have max tornado counts larger than any eastern states except for IL, MS and FL!

## TC tornado outbreaks: records

- August established a new max tornado count in 2004, with 182 (partly due to TCs)
- September established a new max tornado count in 2004, with 297 (275 due to TCs)
- 2004 total tornado count of 1819 smashes previous record of 1424 in 1998; TC contribution of 339 was important

## TC tornado outbreaks: forecasts

- Potential for outbreaks was evident from synoptic and mesoscale analyses, at least for Frances, Ivan and Jeanne
- For the first time, SPC issued MDT RISK outlooks for these TCs, and they generally verified well

## Case studies

- Ivan (2004)

## IVAN

## Sounding, Tallahassee, 00 UTC

## Sounding characteristics - Ivan

- Buoyant energy was not very large; CAPE near TLH apparently only ~1000 J/kg
- Buoyancy concentrated in lower troposphere
- Very strong veering shear in lower troposphere (0-3 km helicity ~600 J/kg)
- Environments support mini-supercells, with tornadoes, but no hail, little lightning
- See Watson et al poster for radar analyses

##      Tornado from Ivan, Panama City, FL, 15 Sep 2004 

-      Tornado from Ivan, Panama City, FL, 15 Sep 2004
-                                (US Navy photo)

## Tornado, Loudon County, VA, 17 Sep 2004 (Ivan)

## Tornado, Orange County, VA, 17 Sep 2004 (Ivan)

## Case study

- Beryl 1994

## T. S. Beryl

- Surface
- Analysis

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## Slide 28

## *

- +FC after
- final CG

## Conclusions I

- TC tornado totals in 2004, 2005 unprecedented
- Tornado statistics in SE,E may be skewed for decades to come, thanks to Frances and Ivan
- NWS,SPC did well with watches, warnings, but 7 deaths occurred at night (Bonnie=3, Ivan=4)
- Need to educate public better about the peculiar traits of TC tornadic storms
- Must rewrite parts of TC tornado FAQ at TPC!

## Conclusions II

- TCs having enhanced tornado risk are:
- Strong
- Large
- Recurving with midlatitude westerlies
- Hodographs best downshear of TC center
- Gulf coast landfallers
- Moving at 4-8 m/s
- Interacting with weak fronts

## Conclusions III

- TC tornado swarms involve supercells
- TC supercells most common in RF (NE) quad
- 0-3 km helicity often > 150 J/kg
- CAPE often only 500-1000 J/kg
- Storms usually small, shallow, with little LTG
- More LTG -> stronger storms, BUT...
- Lulls in CGs -> tornadoes (sometimes)
- Meso signatures hard to detect at r > 100 km
- Beware of any persistent cells

## Acknowledgments

- Tom Grazulis, author of Significant Tornadoes, 1680-1991
- NWS personnel at TBW,MLB,JAX,TLH, ATL,CAE,CHS,GSP,ILM,MHX,RAH, RNK,AKQ,LWX,CTP
- Jason Caldwell, SERCC
- Patrick Michaels, VA State Climatologist
- Dennis Buechler, UAH
- Plymouth State College
- Storm Prediction Center