About

Kelly Lombardo is an Associate Professor of Meteorology and Atmospheric Science at Penn State University, where she also holds the title of Wilson Faculty Fellow. Her research specialties include Atmospheric Dynamics, Climate, Mesoscale Meteorology, and Severe Weather. She earned her Ph.D. in Atmospheric Science from Stony Brook University in 2011, her M.S. in Atmospheric Science from the University at Albany in 2004, and her B.S. in Atmospheric Science from the University at Albany in 2001. Her work focuses on understanding atmospheric processes, with particular attention to dynamics and severe weather phenomena, contributing to the broader field of meteorology through her research and academic activities.

Research topics

• Meteorology
• Climatology
• Geology
• Environmental science
• Atmospheric sciences
• Physics
• Geography
• Mechanics
• Oceanography

Selected publications

• Modifying Windsonds to Improve In-Storm Measurements

  2026-03-10

  articleOpen access

  Abstract. Obtaining reliable thermodynamic and kinematic profiles from within severe convective storms presents a challenge for radiosondes due to the extreme conditions to which the instrumentation is exposed. The Windsond S1 has emerged as a popular tool for severe storm research; however, exposure to heavy precipitation has been recently documented to cause relative humidity (RH) sensor malfunctions, limiting the reliability of in-storm measurements. We introduce modifications to the Windsond S1 design that limit water ingress and thereby mitigate these issues. The modifications include a redesigned radiation shield that blocks falling raindrops while maintaining adequate ventilation, a stabilizing support arm, and a tether seal. Controlled experiments using irrigation-generated precipitation at approximately 300 mm hr-1 demonstrated that unmodified sondes experienced RH sensor failures, suppressed RH variability, and power failures due to water ingress, while modified sondes remained functional throughout the exposure to the extreme rain rate. Validation profiles comparing modified and unmodified sondes launched under varied atmospheric conditions, including nocturnal flights, showed temperature differences of typically less than 1 °C and RH differences less than 10 %, with no systematic biases introduced by the modifications. These design improvements were applied to an extensive number of Windsonds S1 during the 2025 ICECHIP field campaign for in-storm deployments. Tested modifications to the Windsond S1 require minimal expertise to implement. Further, design files have been made publicly available to support the broader severe storms research community.

  PublisherOA PDFDOI

• Windsond S1H2 modifications for observations in rain

  Zenodo (CERN European Organization for Nuclear Research) · 2026-01-13

  datasetOpen access

  Introduction This repository contains 3D model files used to fabricate and modify Windsond S1 radiosondes. The purpose of these modifications is to limit water ingress into the radiosonde electronics during heavy precipitation. A journal article detailing the design and validation can be found here: Link will be added upon publication Printing and Assembly Radiation Shield Print with 0.2 mm layer thickness, 100% infill, and no supports, oriented such that the shield base is on the printing bed. PLA filament is suitable. Printing speed may need to be reduced to prevent print failures. Finished models must be wrapped in adhesive aluminum foil tape to reflect solar radiation. Recommended thickness is 0.04 mm or less. To connect the new radiation shield to the probe arm use the same approach as the original radiation shield - adhesive foil tabs. Note that the probe arm must run through the middle of the radiation shield to allow ventilation. Sensor Support Arm Print with 0.2 mm layer thickness, 100% infill, and no supports, oriented such that the outer long edge is on the printing bed. PLA filament is suitable. Mount by first passing the sensor through the support arm (without a radiation shield). Adhere the support arm to the outside of the polystyrene cup using hot-melt glue. Tether Hole Cover Print with 0.2 mm layer thickness, 100% infill, and no supports, oriented flat on the printing bed. PLA filament is suitable. Ensure the slot remains open, use a craft knife to open it as needed. Place tether through the cover and carefully pull so no slack remains (be careful not to break the tether). Adhere the cover only to the tether using hot melt glue. Additional Recommendations Seal the power switch using a small piece of waterproof tape. Be careful not to touch the exposed T/RH sensor during assembly. All model files are in millimeters

  PublisherDOI

• Investigation of Physical Processes Contributing to Coastal Convection Initiation on 2 June 2022 during ESCAPE

  Monthly Weather Review · 2026-03-31

  article

  Abstract Data obtained during the National Science Foundation (NSF)-funded Experiment of Sea Breeze Convection, Aerosols, Precipitation, and Environment (ESCAPE) field campaign and conventional observations are used to evaluate the physical mechanisms responsible for convection initiation (CI) over coastal Texas during the 2 June 2022 intensive observation period. Failed CI attempts first occurred about 1300 UTC [0800 local time (LT)] along a decaying land breeze located parallel to and offshore of the Texas coastline. Subsequent successful CI, which occurred around 1430 UTC (0930 LT), required the assistance of gravity waves that formed as an upstream MCS cold pool perturbed the stable lower troposphere. Upon the interaction between the leading radar-detected gravity wave and the offshore remnants of the land breeze, convective cells developed along the length of the offshore boundary. Outflow from this line of cells moved inland and initiated new convective cells resulting in widespread convection over the coastal zone that continued past 2000 UTC (1500 LT). Results from this work illustrate the complex chain of mechanisms that can lead to CI over coastal regions and emphasize the challenges encountered by forecasters in predicting coastal CI. Significance Statement Forecasting the timing and location of storm formation is a major challenge, particularly in coastal areas. Understanding the forcing mechanisms responsible for convection initiation is paramount for accurate forecasting. This study provides an in-depth analysis of a single day to determine the causes and characteristics of convection initiation. Our results identify several forcing mechanisms responsible for convection, which helps illustrate the complexities of forecasting in coastal regions.

  PublisherDOI

• Windsond S1H2 modifications for observations in rain

  Zenodo (CERN European Organization for Nuclear Research) · 2026-01-13

  datasetOpen access

  Introduction This repository contains 3D model files used to fabricate and modify Windsond S1 radiosondes. The purpose of these modifications is to limit water ingress into the radiosonde electronics during heavy precipitation. A journal article detailing the design and validation can be found here: Link will be added upon publication Printing and Assembly Radiation Shield Print with 0.2 mm layer thickness, 100% infill, and no supports, oriented such that the shield base is on the printing bed. PLA filament is suitable. Printing speed may need to be reduced to prevent print failures. Finished models must be wrapped in adhesive aluminum foil tape to reflect solar radiation. Recommended thickness is 0.04 mm or less. To connect the new radiation shield to the probe arm use the same approach as the original radiation shield - adhesive foil tabs. Note that the probe arm must run through the middle of the radiation shield to allow ventilation. Sensor Support Arm Print with 0.2 mm layer thickness, 100% infill, and no supports, oriented such that the outer long edge is on the printing bed. PLA filament is suitable. Mount by first passing the sensor through the support arm (without a radiation shield). Adhere the support arm to the outside of the polystyrene cup using hot-melt glue. Tether Hole Cover Print with 0.2 mm layer thickness, 100% infill, and no supports, oriented flat on the printing bed. PLA filament is suitable. Ensure the slot remains open, use a craft knife to open it as needed. Place tether through the cover and carefully pull so no slack remains (be careful not to break the tether). Adhere the cover only to the tether using hot melt glue. Additional Recommendations Seal the power switch using a small piece of waterproof tape. Be careful not to touch the exposed T/RH sensor during assembly. All model files are in millimeters

  PublisherDOI

• How Terrain Geometry and Environmental Instability Shape Precipitation in Mountain-Crossing Mesoscale Convective Systems

  Mendeley Data · 2026-01-15

  datasetOpen accessSenior author

  The dataset was created to enable public access to the numerical simulation results used in the manuscript “How Terrain Geometry and Environmental Instability Shape Precipitation in Mountain-Crossing Mesoscale Convective Systems” by Fan Wu and Kelly Lombardo. This work was supported by the Atmospheric Radiation Measurement (ARM) User Facility (DOE Office of Science) under DE-SC0022913, and by the National Science Foundation under AGS-2002660. The files include model output from multiple numerical experiments described in the paper, designed to isolate the effects of terrain geometry and environmental instability on precipitation in mountain-crossing mesoscale convective systems. All the simulation data was output from Cloud Model 1 (CM1) version 20.3 and post-processed for plotting figures in our research article. Files in CTRL are the y-averaged simulation data for the control experiments initialized by the observed sounding from the Villa Dolores site (S1) at 0000 UTC on 15 March 2019 during the Cloud, Aerosol, and Complex Terrain Interactions (CACTI) field campaign. In the CTRL files, various bell-shaped terrains were configured for the sensitivity of terrain geometry, including mountain width of 50, 100, and 150 km, and crest height of 2.0, 2.5, and 3.0 km. In the other set of sensitivity experiments of environmental instability, we tested initial CAPE values of 1500, 2000, 2500, and 3000 J/kg for each mountain geometry. The corresponding simulation data can be found in the folders of H20W50, H20W100, H20W150, H25W50, H25W100, H25W150, H30W50, H30W100, and H30W150, and each compressed file includes four netCDF files for the four different initial CAPE values. The folder named "Precipitation data" contains the post-processed rainfall data used to produce the figures in the paper. For more information or any questions about the data and our research, please contact Fan Wu (wufan.iap.cas@outlook.com) . Due to the limitation of upload (10 Gb), only precipitation data and CTRL were uploaded. More simulation data can be generated by the model and sounding data uploaded to the folder of Model.

  PublisherDOI

• How Terrain Geometry and Environmental Instability Shape Precipitation in Mountain-Crossing Mesoscale Convective Systems

  Mendeley Data · 2026-01-15

  datasetOpen accessSenior author

  The dataset was created to enable public access to the numerical simulation results used in the manuscript “How Terrain Geometry and Environmental Instability Shape Precipitation in Mountain-Crossing Mesoscale Convective Systems” by Fan Wu and Kelly Lombardo. This work was supported by the Atmospheric Radiation Measurement (ARM) User Facility (DOE Office of Science) under DE-SC0022913, and by the National Science Foundation under AGS-2002660. The files include model output from multiple numerical experiments described in the paper, designed to isolate the effects of terrain geometry and environmental instability on precipitation in mountain-crossing mesoscale convective systems. All the simulation data was output from Cloud Model 1 (CM1) version 20.3 and post-processed for plotting figures in our research article. Files in CTRL are the y-averaged simulation data for the control experiments initialized by the observed sounding from the Villa Dolores site (S1) at 0000 UTC on 15 March 2019 during the Cloud, Aerosol, and Complex Terrain Interactions (CACTI) field campaign. In the CTRL files, various bell-shaped terrains were configured for the sensitivity of terrain geometry, including mountain width of 50, 100, and 150 km, and crest height of 2.0, 2.5, and 3.0 km. In the other set of sensitivity experiments of environmental instability, we tested initial CAPE values of 1500, 2000, 2500, and 3000 J/kg for each mountain geometry. The corresponding simulation data can be found in the folders of H20W50, H20W100, H20W150, H25W50, H25W100, H25W150, H30W50, H30W100, and H30W150, and each compressed file includes four netCDF files for the four different initial CAPE values. The folder named "Precipitation data" contains the post-processed rainfall data used to produce the figures in the paper. For more information or any questions about the data and our research, please contact Fan Wu (wufan.iap.cas@outlook.com) . Due to the limitation of upload (10 Gb), only precipitation data and CTRL were uploaded. More simulation data can be generated by the model and sounding data uploaded to the folder of Model.

  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

• Environmental Characteristics Supporting Warm-Season Coastal Convection Initiation near Houston, Texas

  Weather and Forecasting · 2025-05-07

  articleOpen access

  Abstract Convection initiation (CI) remains a formidable forecasting challenge, particularly along the coast. Examining Houston, Texas, radar observations of isolated cells’ CI spatiotemporal patterns for Junes from 2017 to 2022 revealed three patterns: cells forming exclusively over land (LAND), over coastal waters (GULF), or domainwide, initiating first over land (DW-L) or the water (DW-G). CI and dissipation times varied by regime. LAND events tended to typify the diurnal cycle, whereas GULF events tended to initiate overnight; both had durations < 10 h. In contrast, DW events began overnight and lasted until evening, with durations often exceeding 10–15 h. Synoptic-scale composites for each regime revealed only minimal forcing for ascent, suggesting the local environment’s importance for CI. Composite vertical profiles for CI locations revealed surface-based CAPE > 1500 J kg −1 and CIN > −40 J kg −1 for each regime. LAND had the hottest and driest lowest 1 km AGL, but was moistest between 1 and 2 km, suggesting LAND parcels originating below 1 km may be susceptible to entrainment and require moister midlevels for successful CI. We also found conditional instability below 1 km AGL for all regimes but a stable layer for GULF and neutral layers for LAND and DW-G between 1 and 2 km. This indicates saturation of air parcels within this layer is insufficient for CI, and mechanical lifting (e.g., sea breeze) would be necessary for CI. Indeed, all regimes featured potential instability throughout the lowest 4 km. However, only the LAND regime had a coastal density gradient conducive to sea-breeze formation; this indicates other lifting mechanisms may be important in the other regimes. Significance Statement Forecasting the timing and location of storm formation is a major challenge, particularly in coastal areas. We endeavor to understand storm formation patterns in the Houston, Texas, area, with the main goal of better understanding how precursor atmospheric conditions may favor or disfavor such storm formation. We find four spatial patterns of storm formation: only over the land, only over coastal gulf waters, or over both land and gulf (but starting over land or the gulf). Average large-scale and local conditions were similar for each regime, with only subtle differences in their low-level temperature and humidity profiles. Results suggest that small-scale features like sea breezes thus are required for initiation, but only the LAND regime has sea-breeze-favorable conditions.

  PublisherOA PDFDOI

• Timescales of Evolution for Supercell Updrafts and their Impact on Hail Trajectories

  2025-08-08

  preprintOpen access

  Recent hail trajectory modeling studies have identified pathways for large hail growth that are complex and strongly impacted by sub-updraft scale dynamics in the supercooled layer of a storm. In the hail growth region of a supercell, thermal-like behavior, vortex shedding, and dynamical rotors, among other phenomena, cause an updraft to evolve dynamically on short timescales that may not be clearly resolved by operational radars, which perform volume scans on timescales of 5 min or greater. Here, we examine the evolution of the mixed phase region of a supercell storm’s updraft modeled in CM1 with 5-second temporal output. This dataset provides a sandbox in which to explore the timescales of evolution for a variety of updraft quantities and can shed light on the temporal resolution necessary to resolve properties of a storm’s updraft important for hail trajectories. Techniques including Fourier analysis, wavelet analysis, and variability indices are presented as tools for identifying and isolating updraft variability on a variety of timescales associated with physical and dynamical processes in the modeled supercell. We hypothesize that the treatment of updraft variability in numerical hail trajectory modeling is impactful on the nature of hail trajectories produced (i.e., do hail trajectories have differing complexity if computed in composited storm fields, in frozen snapshots of a storm, or in fully time-varying fields?). To understand the role of temporal variability in hail growth, we run hail trajectories to compare the impact of these different ways of representing storm fields. We examine how allowing or restricting the evolution of a storm impacts the behavior and complexity of numerically modeled hail trajectories. On the recent ICECHIP field campaign, Hailsondes (small probes that are released into a storm, accrete mass, and fall out as pseudo-hailstones) were released to measure hail-like trajectories in real storms. We compare our modeled trajectories to Hailsonde trajectories to analyze the realism of modeled hail trajectories in an evolving storm.

  PublisherDOI

• ICECHIP: PSU NARHWAL Windsond Data. Version 1.0

  Open MIND · 2025-01-01

  datasetOpen access1st authorCorresponding

  Vertical profiles of temperature, relative humidity and winds from the Pennsylvania State University NARHWAL Windsond system that was deployed at locations around the United States plains region for the ICECHIP (In-situ Collaborative Experiment for the Collection of Hail In the Plains) campaign.

  PublisherOA PDFDOI

Recent grants

• Toward a Further Understanding and Improved Forecasting of Coastal Quasi-linear Convective Systems

  NSF · $292k · 2015–2019

Frequent coauthors

• Brian A. Colle

  Stony Brook University

  13 shared

• John R. Gyakum

  McGill University

  11 shared

• Shawn M. Milrad

  Embry–Riddle Aeronautical University

  11 shared

• Eyad H. Atallah

  University of Arizona

  11 shared

• Anji Seth

  University of Connecticut

  11 shared

• Matthew R. Kumjian

  Pennsylvania State University

  11 shared

• Lindsey N. Long

  Centers for Disease Control and Prevention

  8 shared

• Scott R. Stephenson

  RAND Corporation

  8 shared