About

Timothy Logan is an Associate Professor at Texas A&M University in the Department of Atmospheric Sciences and serves as the Director of the Houston Lightning Mapping Array (HLMA) Network. His research focuses on lightning behavior, cloud top discharges, and the charge structure of thunderstorms, employing advanced lightning mapping technologies to analyze phenomena such as jets, gigantic jets, and transient luminous events. His work includes collaborative NSF-funded projects that examine the impacts of aerosols, including wildfire smoke and pollution, on lightning activity and severe weather, utilizing observational data and modeling approaches. Logan's research aims to understand the microphysical and radiative effects of aerosols on deep convection, with a particular emphasis on the Houston metropolitan area and the Gulf Coast region. He also integrates machine learning techniques to analyze convective systems and develop storm intensity prediction models, with future plans to expand the coverage of the HLMA network to study marine and tropical convection impacts.

Research topics

• Physics
• Atmospheric sciences
• Meteorology
• Environmental science
• Climatology
• Geology
• Geography
• Astrophysics

Selected publications

• VHF Source Data Exported Files for the Cypress/Klein and Katy/Splendora Tornado Cases

  Texas Digital Library (University of Texas) · 2026-01-05

  datasetOpen access1st authorCorresponding

  This dataset contains Houston Lightning Mapping Array post-processed VHF source data for the entire path and duration of the Cypress/Klein and Katy/Splendora tornadoes that occurred on 24 November 2025 and 28 December 2024, respectively. The VHF source data is used in all of the scripts discussed in the manuscript

  PublisherDOI

• njcoyote/pseudo-dynamic-hlma-scripts: v1.0.0

  Zenodo (CERN European Organization for Nuclear Research) · 2026-01-09

  otherOpen access1st authorCorresponding

  This archive contains the scripts used to generate the figures for a publication titled "Employing pseudo-dynamic metrics derived from lightning to diagnose tornadic supercell thunderstorm organization and maintenance" submitted to the Journal of Geophysical Research Letters. The workflow uses the raw exported Houston Lightning Mapping Array (LMA) data to extract pseudo-dynamic quanities including pseudo-vorticity, pseudo-tendency, fragmentation and duty cycle. These diagnostics are used to quantify storm evolution and electrical organization in supercell, tornado, sea-breeze and meso-scale convective system (MCS) case studies.

  PublisherDOI

• njcoyote/pseudo-dynamic-hlma-scripts: v1.0.0

  Zenodo (CERN European Organization for Nuclear Research) · 2026-01-09

  otherOpen access1st authorCorresponding

  This archive contains the scripts used to generate the figures for a publication titled "Employing pseudo-dynamic metrics derived from lightning to diagnose tornadic supercell thunderstorm organization and maintenance" submitted to the Journal of Geophysical Research Letters. The workflow uses the raw exported Houston Lightning Mapping Array (LMA) data to extract pseudo-dynamic quanities including pseudo-vorticity, pseudo-tendency, fragmentation and duty cycle. These diagnostics are used to quantify storm evolution and electrical organization in supercell, tornado, sea-breeze and meso-scale convective system (MCS) case studies.

  PublisherDOI

• njcoyote/pseudo-dynamic-hlma-scripts: v0.0.1-beta

  Zenodo (CERN European Organization for Nuclear Research) · 2026-01-09

  otherOpen access1st authorCorresponding

  This is the initial release to trigger a Zenodo archive.

  PublisherDOI

• Studying Aerosol, Clouds, and Air Quality in the Coastal Urban Environment of Southeastern Texas

  Bulletin of the American Meteorological Society · 2025-08-04 · 3 citations

  article

  Abstract A multi-agency succession of field campaigns was conducted in southeastern Texas during July 2021 through October 2022 to study the complex interactions of aerosols, clouds and air pollution in the coastal urban environment. As part of the Tracking Aerosol Convection interactions Experiment (TRACER), the TRACER- Air Quality (TAQ) campaign the Experiment of Sea Breeze Convection, Aerosols, Precipitation and Environment (ESCAPE) and the Convective Cloud Urban Boundary Layer Experiment (CUBE), a combination of ground-based supersites and mobile laboratories, shipborne measurements and aircraft-based instrumentation were deployed. These diverse platforms collected high-resolution data to characterize the aerosol microphysics and chemistry, cloud and precipitation micro- and macro-physical properties, environmental thermodynamics and air quality-relevant constituents that are being used in follow-on analysis and modeling activities. We present the overall deployment setups, a summary of the campaign conditions and a sampling of early research results related to: (a) aerosol precursors in the urban environment, (b) influences of local meteorology on air pollution, (c) detailed observations of the sea breeze circulation, (d) retrieved supersaturation in convective updrafts, (e) characterizing the convective updraft lifecycle, (f) variability in lightning characteristics of convective storms and (g) urban influences on surface energy fluxes. The work concludes with discussion of future research activities highlighted by the TRACER model-intercomparison project to explore the representation of aerosol-convective interactions in high-resolution simulations.

  PublisherDOI

• Comparison study of the electrical nature of two smoke-enhanced sea breeze thunderstorm cases during TRACER

  2025-04-24

  preprintOpen access1st authorCorresponding

  Two cases identified during the Tracking Aerosol Convection Interactions Experiment (TRACER) using a lightning mapping array are presented to demonstrate how lightning observably quantifies aerosol invigoration impacts on sea breeze thunderstorms that initiate in comparable dynamic/thermodynamic environments with smoke aerosols. The 12 July 2022 case directly ingested fresh smoke aerosols from a nearby wildfire and exhibited frequent high altitude VHF lightning sources, strong positive cloud-to-ground pulses (>75 kA), peak accumulated precipitation of nearly 45 mm, and lasted 2.5 hours. The 13 July 2022 case featured broader lightning and precipitation coverage with a lower flash rate, fewer positive cloud-to-ground pulses, lower peak precipitation (~21 mm), and lasted 3.5 hours. Both cases exhibited aerosol invigoration effects with the 12 July 2022 case showing a stronger signal. Future work involves identifying and modeling additional TRACER thunderstorm cases to help qualitatively disentangle aerosol-dynamic impacts on lightning behavior and charge structure, precipitation, and spatiotemporal coverage.

  PublisherOA PDFDOI

• A New WMO-Certified Single Megaflash Lightning Record Distance: 829 km (515 mi) Occurring on 22 October 2017

  Bulletin of the American Meteorological Society · 2025-07-31 · 1 citations

  articleOpen access

  Peer Reviewed

  PublisherOA PDFDOI

• Comparison study of the electrical nature of two smoke-enhanced sea breeze thunderstorm cases during TRACER

  2025-07-14

  preprintOpen access1st authorCorresponding

  Sea breeze thunderstorms identified during the Tracking Aerosol Convection Interactions Experiment (TRACER) were analyzed in terms of their responses to aerosol influences under comparable dynamic/thermodynamic environments over a selected baseline study period (9-18 July 2022). The U. S. Department of Energy Atmospheric Radiation Measurement Mobile Facility (AMF) Aerosol Observation System (AOS) and the Houston Lightning Mapping Array (HLMA) provided the primary aerosol and lightning information. Aerosol loading and lightning activity were most notable on 11-14 July 2022. On 12 July 2022, sea breeze convection directly ingested smoke aerosols from a wildfire and exhibited the highest lightning flash rate of the study period, generated frequent small lightning flashes with positive pulse peak currents exceeding 50 kA, and featured intense precipitation (~44 mm). The 13 July 2022 sea breeze convection case initiated in nearly the exact same location and time in a polluted, post-fire environment. The convection featured a lower lightning flash rate with only two strong positive pulses, lightning flashes with larger spatial coverage on average, and lower peak precipitation (20 mm). Both cases exhibited normal dipole charge structures with the 13 July 2022 case having a more pronounced low-level positive charge layer. Both cases initiated in moist environments (RH>65%) with comparable convective available potential energy (CAPE) values in excess of 4800 J kg-1. Future work involves identifying more sea breeze thunderstorm cases to be modeled in terms of their responses to aerosol influences using lightning and charge structure as additional parameters.

  PublisherOA PDFDOI

• Occurrence of rare lightning events during Hurricane Nicholas (2021)

  2024-05-10

  preprintOpen access1st authorCorresponding

  Hurricane Nicholas was classified as a Category 1 tropical cyclone (TC) at 0000 UTC on 14 September 2021 and made landfall along the upper Texas Gulf Coast at 0530 UTC with maximum sustained winds of 33 m s-1. Much of the electrical activity during Nicholas was monitored by the Houston Lightning Mapping Array (HLMA) network. Deep convection developed in the rainband at 1700 UTC on 13 September, diminished by 2030 UTC, and re-intensified after 2200 UTC. At 2004 UTC (13 September), a curved megaflash (~220 km) was observed by the HLMA in the stratiform precipitation region of the outer rainband. By 0130 UTC on 14 September 2021, vigorous deep convective cells developed in the eastern eyewall region and propagated cyclonically to the western eyewall region. Several “jet-like” transient luminous events (TLEs) were observed by the HLMA emanating from a deep convective cell in the western eyewall region between 0230-0300 UTC with VHF source points ranging from 30-45 km in altitude. Moreover, the TLEs occurred within a region of strong wind shear, upper-level graupel-ice crystal collisions (~15 km), and strong cloud top divergence. Charge analysis of the deep convection during Nicholas revealed an overall normal dipole structure, while the megaflash and TLE deep convective cases exhibited inverted dipole charge structures. Dissipation of the upper-level screening charge layer resulting from cloud top divergence likely played a role in the observed TLE VHF sources escaping to altitudes exceeding 30 km.

  PublisherOA PDFDOI

• Assessing Radiative Impacts of African Smoke Aerosols Over the Southeastern Atlantic Ocean

  Earth and Space Science · 2024-04-01 · 3 citations

  articleOpen access1st authorCorresponding

  Abstract Biomass burning smoke aerosols are efficient at attenuating incoming solar radiation. The Layered Atlantic Smoke Interactions with Clouds campaign was conducted from June 2016 to October 2017. The U. S. Department of Energy mobile Atmospheric Radiation Measurement site located on Ascension Island (AMF‐ASI) identified several instances of smoke plume intrusions. Increases in surface and column measurements of aerosol loading were directly related to increases in fine mode fraction, number concentrations of aerosols ( N a ), and cloud condensation nuclei ( N CCN ). During periods of weak lower tropospheric stability, smoke particles were more likely to be advected downward either by boundary layer turbulence or cloud top entrainment under non‐overcast sky conditions. Backward trajectory analysis illustrated that smoke aerosols reaching the AMF‐ASI site were fine mode, less aged, strongly absorbing, and had shorter boundary layer trajectories while longer boundary layer trajectories denoted mixtures of weakly absorbing smoke and coarse mode marine aerosols. The most polluted smoke cases of August 2016 and 2017 revealed a notable contrast in radiative forcing per unit aerosol optical depth or radiative forcing efficiency (Δ F eff ) at the top of the atmosphere (TOA) and near‐surface (BOA). The weakly (strongly) absorbing 2016 cases exhibited weaker (stronger) Δ F eff at the TOA and BOA suggesting a warming (cooling) effect within the boundary layer. The 2017 cases featured the strongest Δ F eff suggesting more of a cooling effect at the TOA and BOA due to mixing of fresh smoke with marine aerosols during transport.

  PublisherOA PDFDOI

Recent grants

• Collaborative Research: Evaluating the Influences of Aerosols on Low-level Cloud-precipitation Properties over Land and Ocean using Ground-based Observations and WRF Simulations

  NSF · $85k · 2017–2020

Frequent coauthors

• Yuan Wang

  Stanford University

  27 shared

• Xiquan Dong

  27 shared

• Baike Xi

  University of Arizona

  26 shared

• Xiaojian Zheng

  University of Arizona

  16 shared

• Brendan Lawrence

  Mitchell Institute

  13 shared

• Jacob Hale

  Mitchell Institute

  13 shared

• Sydney Butler

  Mitchell Institute

  13 shared

• Yuk L. Yung

  California Institute of Technology

  11 shared

Labs

• Atmospheric Sciences Research LabPI

Awards & honors

• 2015: TAMU Atmospheric Science Department Outstanding Facult…
• 2015: Hubei Province, China Scientific Paper Award
• 2014: American Meteorological Society Best Student Poster Aw…
• 2011: National Science Foundation East Asian and Pacific Sum…