Relations Between Lightning Bursts in TC Cores and Intensity Changes

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Relations Between Lightning Bursts in TC Cores
and Intensity Changes

• Henry Fuelberg
• Matt Onderlinde
• Scott Rudlosky
• Zak Tamurian
• Florida State University

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Background

• Impressive improvements in TC track forecasts
• TC intensity forecasts have not kept pace
• Improvements may occur by focusing on
  characteristics of TC coresDr. Bob Hart (FSU)
• We are focusing on core lightning
• Project began January 1, 2009

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Motivation

• What do lightning bursts tell us about TC
  intensification or de-intensification?
• What do lightning bursts serve as a proxy for?
• Do hot towers (lightning) play an active role, or
  are they a passive indicator of larger scale
  forcing?
• What core physical process are involved?

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Objectives

• Diagnostic studies
• Vaisala LLDN and NLDN data
• Radar data where available
• WDSS-II software
• Satellite imagery
• WRF Simulations
• Two way nesting
• 27 km, 9 km, 3 km, 1 km
• Parameterize lightning using
• Dierling et al. (2005) on cloud scale (ice
  fluxes)
• Hopkins and Fuelberg (2009) on regional scale
• (relate storm tops to flash rate)

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Gustav 2008

• TC positions at 3 h intervals
• Vaisala LLDN CG flashes (derived from strokes)
  within a 100 km radius of the TC center and
  1.5 h of each 3 h position
• TC Strength Flash Density

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Density of Flashes Linked with Storm
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Gustav Time Series
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Gustav Time Series
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1.5 h LLDN CG Flashes
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1.5 h LLDN CG Flashes
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Katrina August 2005

• WSR-88D images at 6 min intervals
• NLDN lightning at 1 min intervals
• Loop starts at 1920 UTC 25 Augustat the start of
  a lightning burst
• Katrina first reached hurricane status 2 h prior
  to landfall (midway through our loop)
• Loop ends at 2220 UTC 25 Augustas the storm
  approaches the FL Coast with a more defined eye
  wall

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2047 UTC 25 August--North
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2047 UTC 25 August--Central
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2047 UTC 25 August--South
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Extratropical Transition of Hurricane Frances 2004
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Conclusions

• Just beginning the research
• Results will be forthcoming