The Memphis Tornado Project

1
The Memphis Tornado Project

• Jonathan L. Howell Scott J. McNeil Kati R.
  McNeil Todd A. Beal Chris A. Duke Anthony
  R. Cavallucci
• National Weather Service - Memphis, TN

2
Project Overview

• Investigate Weather Patterns Favorable For
• Strong Tornado Environments (EF2 EF5)
• Weak Tornado Environments (EF0 EF1)
• Non-Tornado Severe Environments
• Mixed Mode Severe Weather Environments
• Primary Goal to Enhance Severe/Tornado
  Forecasting
• Better warnings
• Enhanced Severe Weather Conference Calls
• Severe Weather Education (ex Peak Months)

3
Tornado Severe Databases

• Local Tornado Database was Created from Several
  Sources
• Grazulis Significant Tornado Publication (1873
  1995)
• SPC Tornado Database (1950 1995)
• Storm Data (1950 Present)
• Database Useful for Local Research, Emergency
  Managers, and Public Use
• Available from WFO Memphis Homepage via Miss.
  State Univ.

4
Tornado Databasewww.midsouthtornadoes.msstate.edu

5
Tornado Databasewww.midsouthtornadoes.msstate.edu

6
Tornado Databasewww.midsouthtornadoes.msstate.edu

7
(No Transcript)
8
Synoptic Mesoscale Pattern Recognition

• Use North American Regional Reanalysis (NARR)
  Data to Examine Individual Severe Weather Events
  (1979 Present)
• Create Surface Upper Air Analyses Using the
  Grid Analysis Display System (GRADS)
• Overlay Parameters Important to the Evolution of
  Particular Severe Weather Events
• Identify Large Scale Forcing Mechanisms /
  Boundaries Investigate Any Possible
  Distinguishing Pattern Differences
• Discriminate Between Cool Warm Season Events
• Identify Anomalous Patterns

9
Strong Tor 1000mb/PWAT Anomalies
10
What is the North American Regional Reanalysis
(NARR)?

• NCEP ETA Model Data Assimilation System
• 32 km 45 Layer Resolution
• Data Output Every 3 Hours (1979 Present)
• The Data Set Includes
• Rawinsondes
• Dropsondes
• Pibals
• Aircraft Data
• Surface Data
• GOES Satellite Data
• Etc.

11
NARR Analysis 1/17/99
12
Thermodynamic Environments

• Determine Favorable Thermodynamic Environments
• Validate the NARR Dataset by Comparing NARR
  Proximity Soundings to RAOBs at Surrounding Sites
  (LZK, JAN, BNA, BMX/CKL)
• Create NARR Proximity Soundings for Each Tornado
  Event in Memphis CWA
• /- 0-3 Hours From Tornado Occurrence To
  Preserve Near Real-Time Environmental Conditions
• Modify Soundings with Actual Observed Surface
  Data

13
NARR Proximity Sounding Validation

• NARR Sounding in
• Red/Green
• LZK RAOB in
• Purple
• March 16, 1984 -
• 00z
• F4 Poinsett Co.
• 5 Fatalities

14
Thermodynamic Environments

• Identify Local Thresholds of Instability / Shear
  / Other Derived Parameters
• Low Level Moisture Thresholds
• Low Deep Layer Shear Thresholds
• Combined Moisture / Shear Thresholds
• Other Identified Parameters

Craven et. al., 1999
15
Why Conduct This Study

• Since 1997, 68 tornado deaths have occurred in
  the Memphis CWA (11 of the nations deaths)
  despite timely warnings
• Major Memphis CWA Killer Tornado Events
• April 2nd 2006 Tornado Event (26 Fatalities)
• May 3-12 2003 Tornado Outbreak (11 Fatalities)
• January 17-21 1999 Tornado Outbreak (9 Fatalities)

16
Why Conduct This Study

• Improve WFO Memphis Severe Weather Forecast
  Operations
• Develop Useful Parameter Breakpoints to Improve
  Forecaster Confidence in Determining Storm Mode
• Provide Meaningful Feedback to SPC for Watch
  Coordination

17
Why Conduct This Study

• Enhance Local Public Severe Weather Products
  HWO/SPS
• Provide Detailed Storm Threats to Emergency
  Managers Public Partners for Local Severe Wx
  Conference Calls

18
Summary

• Overall Goal is to Identify Most Prominent
  Environments Leading to Differing Local Severe
  Events
• Strong Tornado
• Weak Tornado
• Non Tornado
• Assist Forecasters in Providing Emergency
  Management Community and the Public Enhanced
  Severe Weather Forecasts and Warnings

19
Special Thanks

• Richard Thompson SPC
• Jared Guyer SPC
• Steven Weiss SPC
• Jeff Evans SPC
• Richard Grumm WFO State College, PA