Tornadogenesis In the beginning, there was well, uh, that depends

Impact on policy from three severe weather events in the Omaha area in June, 2008Daniel Nietfeld NOAA/NWS/WFO Omaha NE

(and many other issues raised)Kansas City IWT Workshop: Using the WAS*IS Approach January 22, 20091Is this something you would want to be warned about? Would you expect the sirens to be blown?

2What was that ?Did it seem dangerous, or even life-threatening?Rear flank downdraft (straight-line winds)Behind a tornadic supercell (Hallam, NE)What would be the best way to handle this scenario with a warning, and any associated siren blowing ???What would be a good polygon solution for this scenario ???3May 22, 2004 Hallam, Nebraska F4

T4June 8 2008: Omaha, Nebraska(mid-morning)

5June 8 2008: Omaha, Nebraska

NWS WCMHome OwnerSaw62:10 2:30 AM June 8 2008

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Storm-Relative Velocity

9The Omaha Policy on 8 June, 2008

Sound the sirens when the NWS issues a tornado warning

IT HI T WITHOUT ANY WARNING !!!!!(From the NWS, or from a siren perspective)10June 8 2008: Omaha, Nebraska

NWS WCMHome OwnerSaw11The Aftermath of 8 JuneSignificant outcryMeeting with the Mayor and StaffPress Conference3 days of news coverage

Google Omaha Tornadoes June 8

1211 June 2008

Xavier

14 Yr Old Boy Scout

Note the scar13

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1811 June 2008

4 Killed

48 Injured19

20Had an outdoor warning device and NOAA Weather Radio

21Boy Scout Policy ChangesMust camp with a Severe Wx Trained adultSevere weather training coursesInvolving the IWT in groups such as Boy ScoutsSirens / Outdoor warning devicesStorm Shelters22

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What IF ? Do you want a TOR Inside a SVR ???26

27June 11, 2008 Tornado Warnings in the Omaha AreaTornado Warnings off/on 715 pm 10 pmSirens off/on for nearly 3 hoursWere polygons too large?(We were operating without a radar at times)Should we take these political boundaries into account? 2827 June 2008

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3-D KOAX Reflectivity at 2159 UTC (courtesy GR Level 2 Analyst)

31June 27, 2008

32June 27 Severe ThunderstormHurricane force winds Lasting for several minutesDamage and debris was widespreadNO TORNADOES

(?What is the best product for this scenario?)

Damage Survey

Event Impacts

Storm statistics:Path length: 90 milesPath width: 4 to 6 milesEstimated maximum wind speeds: 110-115 mph (EF2)One fatality (tree fell on car in Council Bluffs, IA) and several minor injuriesDamage estimate: $53+ million in Douglas County (Omaha) MOTIVATION! New Policy from Lessons Learned! When to activate:When the National Weather Service initiates a Tornado Warning for any portion of Douglas County. When a public safety official or trained storm-spotter states that s/he is in site of a rotating funnel cloud or tornado within Douglas County.When Douglas County 911 receives credible reports of damage or the eminent threat of hurricane-force sustained winds equal to or greater than 74 mph.

36New PolicyDuring night-time conditions or in the absence of adequate warning, the on-duty 911 supervisor can direct an activation of the outdoor warning sirens if he/she determines that lives may be saved and injuries averted by alerting the public to the severe weather condition.

Getting a bit vague here 37ConclusionsOriginal Policy was product driven and failed when the science did not permit the proper product to be issuedRevised Policy was more impact driven, and worked when a life-threatening (but non-tornadic) weather event occurred38What other lessons can be learned (?) Kansas City Metro area ?Lincoln, Nebraska spotter sighting onlyMinimizing False AlarmsFlash flood policies ? 39Post-Event ActivitiesJune 8Local Media flurryLive press conference with Mayor and 911 DirectorJune 11National MediaJune 27Local MediaInsurance companies, lawyers, roofing companies, etc.40

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43Discussion QuestionsSiren Policies

Scout Camp issuesSheltersSirensShould NWS Warnings have GIS data? (camps, etc)

Polygon methodologiesProducts that fit the event (wide range of Severe)

44Impact on policy from three severe weather events in the Omaha area in June, 2008Daniel Nietfeld NOAA/NWS/WFO Omaha NE

(and many other issues raised)Kansas City IWT Workshop: Using the WAS*IS Approach January 22, 200945