THE BARON TORNADO INDEX (BTI) Presented by: Matt Havin

WHAT IS THE BTI? The Baron Tornado Index An integration of the latest available mesoscale model data combined with single-site radar data, used for advanced analysis of storms during potentially tornadic events 4/26/2017 Matt Havin

The Baron Tornado Index How does it work? The BTI ranks each storm for tornadic potential in the continental U.S. on a 1-10 scale, all in real-time. Weak storms are rated a 1, and the strongest storms with a likely tornado are rated a 10. 4/26/2017 Matt Havin

What meteorological data is used to produce the BTI? The Baron Tornado Index What meteorological data is used to produce the BTI? Data is taken in real-time from every NWS radar site within the continental United States (CONUS) From this radar data, all storms in CONUS are identified and ranked based upon a variety of attributes, including: Reflectivity Velocity VIL (hail cores) Baron shear markers Additional radar attributes 4/26/2017 Matt Havin

What meteorological data is used to produce the BTI? The Baron Tornado Index What meteorological data is used to produce the BTI? After ranking the storms from the radar data, we then look at numerical model data to determine if the mesoscale environment is conducive for tornadoes We currently use the operational Rapid Update Cycle (RUC) from NCEP for model data, and will switch to the Rapid Refresh (RR) in 2010 To match up the real-time radar data of the storm to that of a numerical model, we do an interpolation of the model data down to 1 minute increments 4/26/2017 Matt Havin

What meteorological data is used to produce the BTI? The Baron Tornado Index What meteorological data is used to produce the BTI? When looking at the RUC model data, there are a few numerical model products that we focus a lot of attention on when looking for tornadoes Research performed by meteorologists at the Storm Prediction Center, the NWS, and in the private sector, has shown that the majority of tornadoes occur with CAPE between 1500-3500 J/kg, 0-1km SRH values between 150-300 m2/s2, and LCL heights below 1300 meters 4/26/2017 Matt Havin

What meteorological data is used to produce the BTI? The Baron Tornado Index What meteorological data is used to produce the BTI? After processing both the radar (NEXRAD) and model data (RUC), we then produce a BTI number for all the storms in the continental U.S. We are able to do this using algorithms developed from performing hundreds of tornado case studies that looked at all these pieces of data 4/26/2017 Matt Havin

The Baron Tornado Index How long has it been operational? What successes has it had since its release? The BTI has been used in the broadcast industry since Jan. 2008. The first tornadic event that the BTI was used in was the Super Tuesday tornado outbreak on Feb. 5th, 2008, where it pinpointed numerous deadly tornadoes across much of the South. 4/26/2017 Matt Havin

GEORGIA TORNADOES – FEB. 18th The Baron Tornado Index GEORGIA TORNADOES – FEB. 18th The BTI hit 7+ on several different tornadic storms on the night of February 18th. The EF-2 tornado that passed south of Peachtree City had a 7.4 BTI before touchdown, and tracked for 20 miles. 4/26/2017 Matt Havin 9

MURFREESBORO, TENNESSEE – APRIL 10TH The Baron Tornado Index MURFREESBORO, TENNESSEE – APRIL 10TH On Good Friday, a fatal tornado rated EF-4 struck Murfreesboro. The BTI hit 9.4 more than 10 minutes before the tornado first touched down. The tornado tracked over 23 miles and reached ½ mile wide. 4/26/2017 Matt Havin 10

LAKE GUNTERSVILLE, ALABAMA – APRIL 10TH The Baron Tornado Index LAKE GUNTERSVILLE, ALABAMA – APRIL 10TH A long-track tornado rated EF-3 crossed Lake Guntersville just after 3 PM on Good Friday. The tornado caused extensive damage to lake houses on Preston Island during the 28 mile track. 4/26/2017 Matt Havin 11

LAKE GUNTERSVILLE, ALABAMA – APRIL 10TH The Baron Tornado Index LAKE GUNTERSVILLE, ALABAMA – APRIL 10TH A long-track tornado rated EF-3 crossed Lake Guntersville just after 3 PM on Good Friday. The tornado caused extensive damage to lake houses on Preston Island during the 28 mile track. 4/26/2017 Matt Havin 12

GOSHEN COUNTY, WYOMING – JUNE 5TH The Baron Tornado Index GOSHEN COUNTY, WYOMING – JUNE 5TH An EF-2 tornado was tracked by the VORTEX2 team on the afternoon of June 5th. Doppler on Wheels measured wind speeds of 130 mph near the ground. BTI hit 7.1 at the time tornado was first spotted. 4/26/2017 Matt Havin

GOSHEN COUNTY, WYOMING – JUNE 5TH The Baron Tornado Index GOSHEN COUNTY, WYOMING – JUNE 5TH An EF-2 tornado was tracked by the VORTEX2 team on the afternoon of June 5th. Doppler on Wheels measured wind speeds of 130 mph near the ground. BTI hit 7.1 at the time tornado was first spotted. 4/26/2017 Matt Havin 14

Strategies for using the BTI effectively on the air The Baron Tornado Index Strategies for using the BTI effectively on the air Look for high BTI values (7-10), especially on an isolated storm or supercell. Example: May 10th, 2008 - Stuttgart, AR storm with a BTI of 10 produced 20+ mile long-tracked tornado that produced EF-3 damage Comparison of all BTI values in your DMA (one storm has 5 BTI, ten other storms have a 2 BTI) Example: April 10th, 2008 - Southeast Iowa stacked low pressure event. Many tornadoes with BTI of 4-6, and all others storms with BTI of 1-3 and no tornado Increasing trend in BTI (storm going from BTI of 3 to 5 to 7 within 15 minutes) Example: March 14th, 2008 – downtown Atlanta tornado rapidly increased from 3 BTI to 7 BTI and produced the tornado soon afterwards 4/26/2017 Matt Havin

WHEN TO EXERCISE CAUTION WHEN USING THE BTI The Baron Tornado Index WHEN TO EXERCISE CAUTION WHEN USING THE BTI Always keep in mind that the BTI is an automated tornado detection algorithm. Like anything else in the weather world, it is far from perfect. Here are common situations where the BTI may not detect tornadoes: Tropical storms/hurricanes Tornadic features often too small/atypical to be detected by NWS NEXRAD radar…which lowers BTI. Cold-core low pressure systems Marginal CAPE (<500J/kg) and low-topped mini-supercells make the overall tornadic potential look less likely, which lowers the BTI. However, somewhat useful when looking for relative BTI values between 2-5. 4/26/2017 Matt Havin

Leading the next generation of tornado detection improvements The Baron Tornado Index Leading the next generation of tornado detection improvements The BTI was introduced to the broadcast industry nationwide in January 2008, and has already proven to be highly effective at detecting a storm ripe for tornado development with lead times of 15-30 minutes on numerous occasions Upcoming model improvements, such as the replacement of the RUC with the Rapid Refresh model in 2010, should help meteorologists and the BTI be more effective at identifying potentially tornadic events Improvements in radar technology, such as the upcoming dual-polarimetric NEXRAD upgrade by L-3 Communications and Baron Services, should help lower false alarm rates and improve lead times beyond the limits of currently available technology 4/26/2017 Matt Havin