1. The April 9 th Tornado Outbreak Across the Four-State Region By Nick Fillo & Ismari Ramos WFO Shreveport, LA 4 th Regional Severe Storms/Radar and Hydrology Conference August 13 th – 14 th, 2009

2. What we’ll cover… Brief tornado climatology of the region. Brief tornado climatology of the region. The significance of this event: The largest tornado outbreak for the four-state region in 9 years. The significance of this event: The largest tornado outbreak for the four-state region in 9 years. Explore the atmospheric conditions leading up to the outbreak and what triggered the event. Explore the atmospheric conditions leading up to the outbreak and what triggered the event. Where the tornadoes occurred. Where the tornadoes occurred. The anti-cyclonic Center Point, AR tornado. The anti-cyclonic Center Point, AR tornado. The Shreveport / Bossier City / Barksdale AFB tornado. The Shreveport / Bossier City / Barksdale AFB tornado. A few photos of the damage from these storms. A few photos of the damage from these storms.

3. Tornado Climatology

4. Outbreak Details Strongest outbreak in the Shreveport forecast region since the Easter Sunday Outbreak of 2000. Strongest outbreak in the Shreveport forecast region since the Easter Sunday Outbreak of 2000. This storm system was ultimately responsible for producing more than 60 tornadoes across 11 states, from Texas to the Carolinas. This storm system was ultimately responsible for producing more than 60 tornadoes across 11 states, from Texas to the Carolinas. The event in the Shreveport forecast region started around 6 PM on the 9 th as an upper level trough passed over a very pronounced dry line. The event in the Shreveport forecast region started around 6 PM on the 9 th as an upper level trough passed over a very pronounced dry line. The dry line progressed unusually far to the east, passing to the east of the Dallas Metroplex. The dry line progressed unusually far to the east, passing to the east of the Dallas Metroplex. 13 tornadoes affected 12 counties & parishes. 13 tornadoes affected 12 counties & parishes. No fatalities in the Shreveport forecast region, and only a few injuries. No fatalities in the Shreveport forecast region, and only a few injuries. 3 EF-0, 4 EF-1, 4 EF-2 & 2 EF-3 storms. 3 EF-0, 4 EF-1, 4 EF-2 & 2 EF-3 storms.

5. Easter Sunday 2000 Recap

6. Atmospheric Conditions 7 PM April 9 th 2009 (10/00Z) 500 Mb Height & WV Imagery

7. Atmospheric Conditions 7 PM April 9 th 2009 (10/00Z) Surface Analysis Dry Line Warm Front

8. Atmospheric Conditions 7 PM April 9 th 2009 (10/00Z) RAOB Data

9. Atmospheric Conditions 7 PM April 9 th 2009 (10/00Z) RAOB Data Severe Weather Sounding Analysis for 9 April 2009 7 p.m. Convective available potential energy (CAPE) 1600 J/KG Lifted Index -5.9 Helicity for rotating storm ( ≥ 150 m²/s²) 329 m²/s² Helicity for tornadoes ( ≥ 90 m²/s²) ( ≥ 90 m²/s²) 290 m²/s² Surface to 6 km wind shear ( ≥ 36 KTS) 60 KTS Surface to 1 km wind shear ( ≥ 16 KTS) 30 KTS Lifted Condensation Level ( LCL) (≤ 3500 FT) ~2000 FT

10. Radar Imagery of the Event

11. Tornado Tracks 1. McCurtain Co. OK, Sevier & Howard County AR Tornado 1. McCurtain Co. OK, Sevier & Howard County AR Tornado 2. Center Point, AR Tornado (Anti- cyclonic Tornado) 2. Center Point, AR Tornado (Anti- cyclonic Tornado) 3. Hughes Springs, TX Tornado 3. Hughes Springs, TX Tornado 4. Linden, TX Tornado 4. Linden, TX Tornado 5. Cass County, TX Tornado 5. Cass County, TX Tornado 6. Miller County, AR Tornado 6. Miller County, AR Tornado 7. North Bossier Parish, LA Tornado 7. North Bossier Parish, LA Tornado 8. Union Parish, LA Tornado 8. Union Parish, LA Tornado 9. Harrison County, TX Tornado 9. Harrison County, TX Tornado 10. Harrison Co. TX, Caddo & Bossier Parish, LA Tornado 10. Harrison Co. TX, Caddo & Bossier Parish, LA Tornado 11. Webster Parish, LA Tornado 11. Webster Parish, LA Tornado 12. Lincoln Parish, LA Tornado 12. Lincoln Parish, LA Tornado 13. Jackson & Ouachita Parish, LA Tornado 13. Jackson & Ouachita Parish, LA Tornado

12. Center Point, AR Tornado This tornado was the result of a thunderstorm which split near the city of Dekalb in Bowie County TX. This tornado was the result of a thunderstorm which split near the city of Dekalb in Bowie County TX. While the right half of the storm continued to the east, the left half pushed northeast at around 80 mph. The left half was rotating anti-cyclonically. While the right half of the storm continued to the east, the left half pushed northeast at around 80 mph. The left half was rotating anti-cyclonically. While radar imagery indicated strong rotation along the path of the storm, no damage was observed until the town of Center Point. While radar imagery indicated strong rotation along the path of the storm, no damage was observed until the town of Center Point. This rare anti-cyclonic tornado produced EF-2 damage, with estimated winds of up to 125 mph. This rare anti-cyclonic tornado produced EF-2 damage, with estimated winds of up to 125 mph. Tornado path was 2.5 miles long, and was several hundred yards wide. Tornado path was 2.5 miles long, and was several hundred yards wide. Based on damage, tornado was only on the ground for about 3 minutes. Based on damage, tornado was only on the ground for about 3 minutes.

13. Center Point, AR Tornado

14. Cyclonic Rotation Anti-Cyclonic Rotation

15. Shreveport/Bossier/BAFB Tornado Touching down in eastern Harrison County TX and lifting up in southeastern Bossier Parish. Touching down in eastern Harrison County TX and lifting up in southeastern Bossier Parish. Had the longest track for a tornado in the Shreveport forecast region at 38.5 miles, and was up to 500 yards wide at times. Had the longest track for a tornado in the Shreveport forecast region at 38.5 miles, and was up to 500 yards wide at times. Storm was on the ground continuously for about an hour. Storm was on the ground continuously for about an hour. Most notably, this tornado passed just north of Cross Lake, clipped the southern part of downtown Shreveport, and directly through housing and aircraft operations areas of BAFB. Most notably, this tornado passed just north of Cross Lake, clipped the southern part of downtown Shreveport, and directly through housing and aircraft operations areas of BAFB. Storm overturned rail cars and caused widespread damage to homes in the Lakeview Subdivision. Storm overturned rail cars and caused widespread damage to homes in the Lakeview Subdivision. Rated an EF-2 based on the damage it caused. Rated an EF-2 based on the damage it caused.

16. Shreveport/Bossier/BAFB Tornado

17. Cyclonic Rotation

18. A Few Damage Photos Caddo Parish, near I-220 along Cross Lake. Lakeview Subdivision, Caddo Parish Two-story Water Treatment Plant, Howard County, Dierks, Arkansas

19. Questions? or Comments?