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Sciences and Exploration Directorate

Charles Nelson Helms

(Cloud Dynamicist/Instrument Scientist)

Charles Nelson Helms's Contact Card & Information.
Email: charles.n.helms@nasa.gov
Phone: 301.614.5719
Org Code: 612
Address:
NASA/GSFC
 Mail Code 612
 Greenbelt, MD 20771
Employer: UNIV OF MARYLAND COLLEGE PARK

Research Interests

Cloud Dynamics

Entrainment/detrainment, updraft/downdraft dynamics, upscale impacts, observational analysis

Tropical Meteorology

Tropical cyclogenesis, interactions between dry air and deep convection, processes responsible for the initial vertical alignment of vortices

Winter Weather

Mesoscale snowband formation and maintenance, microphysics measurement techniques

Instrument Science

Dropsondes, airborne radar, ice microphysics probes, observational analysis techniques, instrument error analysis

Other

Object tracking algorithms

Positions/Employment

Assistant Research Scientist

University of Maryland -- ESSIC - NASA Goddard Space Flight Cneter

2022 - Present

Postdoctoral Fellow

NASA Postdoctoral Program (NPP) - NASA Goddard Space Flight Center

2018 - 2022

Education

Ph.D. (Atmospheric Science) -- 2018

  • Doctoral Advisor: Lance Bosart
  • University at Albany, State University of New York, Albany, NY
  • Department of Atmospheric and Environmental Sciences
  • Dissertation: Dry air, midlevel flow, and the persistence of deep convection in Atlantic tropical disturbances.

Masters of Science (Meteorology) -- 2012

  • Masters Advisor: Robert Hart
  • Florida State University, Tallahassee, FL
  • Department of Earth, Ocean, and Atmospheric Science
  • Thesis: The evolution of dropsonde-derived kinematic and thermodynamic structures in developing and non-developing Atlantic tropical convective systems.

Undergraduate (Atmospheric Science) -- 2009

  • Research Advisor: Christopher Hennon
  • University of North Caroline at Asheville, Asheville, NC
  • Department of Atmospheric Sciences
  • Thesis: An objective algorithm for the identification of convetive tropical cloud clusters in geostationary imagery.

Professional Societies

American Meteorological Society

2006 - Present

American Geophysical Society

2011 - Present

Professional Service

  • 2020 - Present -- NASA/GSFC 610 Popular Summary Review Committee
  • 2022 -- WMO 10th International Workshop on Tropical Cyclones (IWTC-10)
  • 2022 -- NASA/GSFC Earth Rise Strategic Planning Group: Missions

Awards

  • 2020 -- NASA/GSFC 610AT Technical or Field Campaign Support Award “For Outstanding Field Campaign Support during the Winter 2020 IMPACTS deployment”
  • 2020 -- ISTD Engineering Excellence Group Award, IMPACTS Team
  • 2015 -- NASA Group Achievement Award "For outstanding achievements of the Hurricane and Severe Storm Sentinel (HS3) airborne mission to investigate the factors influencing hurricane intensity change" (2015)
  • 2009 -- University Research Scholar
  • 2009 -- Atmospheric Sciences Departmental Distinction
  • 2008 -- Outstanding Achievement in Undergraduate Research
  • 2007 -- Outstanding Achievement in Undergraduate Research

Other Professional Information

Programming Languages: IDL (mastery), Python (capable), BASH (capable), Fortran (familiar)

Special Experience

Field Experience:

  • 2025 -- Mission scientist, Forecaster, ER-2 radar support. NASA GSFC Lidar Observation and Validation Experiment (GLOVE) Field Campaign
  • 2024 -- Forecaster, ER-2 radar support. NASA Westcoast and Heartland Hyperspectral Microwave Sensor Intensive Experiment (WHyMSIE) Field Campaign
  • 2023 -- ER-2 radar support. NASA Airborne Lightning Observatory for FEGS and TGFs (ALOFT) Field Campaign
  • 2020, 2022, 2023 -- Forecaster, ER-2 radar support. NASA Investigation of Microphysics and Precipitation for Atlantic Coast-Threatening Snowstorms (IMPACTS) Field Campaign
  • 2015 -- Forecaster. Office of Naval Research (ONR) Tropical Cyclone Intensity Experiment (TCI) Field Campaign
  • 2013, 2014 -- Forecaster. NASA Hurricane and Severe Storm Sentinel (HS3) Field Campaign

Visiting Positions:

  • 2020 - 2022 -- Visiting Assistant Research Scientist. ESSIC, University of Maryland
  • 2016 -- Visiting Researcher. NCAR Mesoscale and Microscale Meteorology Lab
  • 2010 -- Visiting Researcher. National Centers for Environmental Information, formerly the National Climatic Data Center

Publications

Refereed

2026. "Microphysical Properties within Regions of Enhanced Dual-Frequency Ratio during IMPACTS.", Journal of the Atmospheric Sciences, 83 (1): 67-85 [10.1175/jas-d-25-0065.1] [Journal Article/Letter]

2025. "The 3D Structure of a Shallow Generating Cell Driven Snowstorm over the Midwest and Its Microphysical Characteristics Determined Using Particle Aspect Ratio: A Case Study from IMPACTS.", Journal of the Atmospheric Sciences, 82 (12): 2581-2609 [10.1175/jas-d-25-0029.1] [Journal Article/Letter]

2025. "Winter precipitation measurements in New England: results from the Global Precipitation Measurement Ground Validation campaign in Connecticut.", Earth System Science Data, 17 (11): 5783-5810 [10.5194/essd-17-5783-2025] [Journal Article/Letter]

2025. "Synthesis of surface snowfall rates and radar-observed storm structures in 10+ years of Northeast US winter storms.", Atmospheric Chemistry and Physics, [10.5194/egusphere-2025-6] [Journal Article/Letter]

2023. "Recent advances in operational tropical cyclone genesis forecast.", Tropical Cyclone Research and Review, 12 (4): 323-340 [10.1016/j.tcrr.2023.12.001] [Journal Article/Letter]

2023. "Retrieval of Normalized Gamma Size Distribution Parameters Using Precipitation Imaging Package (PIP) Snowfall Observations during ICE-POP 2018.", Journal of Applied Meteorology and Climatology, 62 (5): 611-624 [10.1175/jamc-d-21-0266.1] [Journal Article/Letter]

2023. "Evaluation of SWER(Ze) Relationships by Precipitation Imaging Package (PIP) during ICE-POP 2018.", Journal of Hydrometeorology, 24 (4): 691-708 [10.1175/jhm-d-22-0101.1] [Journal Article/Letter]

2022. "A comparative evaluation of snowflake particle shape estimation techniques used by the Precipitation Imaging Package (PIP), Multi-Angle Snowflake Camera (MASC), and Two-Dimensional Video Disdrometer (2DVD).", Atmospheric Measurement Techniques, 15 (22): 6545-6561 [10.5194/amt-15-6545-2022] [Journal Article/Letter]

2022. "Snow microphysical retrieval from the NASA D3R radar during ICE-POP 2018.", Atmospheric Measurement Techniques, 15 (5): 1439-1464 [10.5194/amt-15-1439-2022] [Journal Article/Letter]

2021. "The Impact of a Midlevel Dry Airflow Layer on Deep Convection in the Pre-Gabrielle (2013) Tropical Disturbance on 4–5 September.", Monthly Weather Review, 149 (8): 2695-2711 [10.1175/mwr-d-20-0380.1] [Journal Article/Letter]

2020. "Reducing Errors in Velocity-Azimuth Display (VAD) Wind and Deformation Retrievals from Airborne Doppler Radars in Convective Environments.", Journal of Atmospheric and Oceanic Technology , 2251–2266 [https://doi.org/10.1175/JTECH-D-20-0034.1] [Journal Article/Letter]

2015. "The Evolution of Dropsonde-Derived Kinematic and Thermodynamic Structures in Developing and Nondeveloping Atlantic Tropical Convective Systems.", Monthly Weather Review, 143 (8): 3109-3135 [10.1175/mwr-d-14-00242.1] [Journal Article/Letter]

2013. "A Polygon-Based Line-Integral Method for Calculating Vorticity, Divergence, and Deformation from Nonuniform Observations.", Journal of Applied Meteorology and Climatology, 52 (6): 1511-1521 [10.1175/jamc-d-12-0248.1] [Journal Article/Letter]

2013. "Tropical Cloud Cluster Climatology, Variability, and Genesis Productivity.", Journal of Climate, 26 (10): 3046-3066 [10.1175/jcli-d-12-00387.1] [Journal Article/Letter]

2011. "An Objective Algorithm for Detecting and Tracking Tropical Cloud Clusters: Implications for Tropical Cyclogenesis Prediction.", Journal of Atmospheric and Oceanic Technology, 28 (8): 1007-1018 [10.1175/2010jtecha1522.1] [Journal Article/Letter]

2011. "Globally Gridded Satellite Observations for Climate Studies.", BAMS, 92 (7): 893-907 [10.1175/2011BAMS3039.1] [Journal Article/Letter]

Non-Refereed

2025. "Reprocessed TRMM Brazil (1999) EDOP Radar Dataset.", NASA GHRC, [http://dx.doi.org/10.5067/TRMMBRAZIL/EDOP/DATA101] [Dataset]

2025. "Reprocessed TCSP (2005) EDOP Radar Dataset.", NASA GHRC, [http://dx.doi.org/10.5067/TCSP/EDOP/DATA201] [Dataset]

2025. "Reprocessed TC4 (2007) EDOP Radar Dataset.", NASA GHRC, [http://dx.doi.org/10.5067/TC4/EDOP/DATA101] [Dataset]

2025. "Reprocessed HOPEX (1995) EDOP Radar Dataset.", NASA GHRC, [http://dx.doi.org/10.5067/HOPEX/EDOP/DATA101] [Dataset]

2025. "Reprocessed CRYSTAL-FACE (2002) EDOP Radar Dataset.", NASA GHRC, [http://dx.doi.org/10.5067/CRYSTALFACE/EDOP/DATA101] [Dataset]

2025. "Reprocessed CAMEX-4 (2001) EDOP Radar Dataset.", NASA GHRC, [http://dx.doi.org/10.5067/CAMEX4/EDOP/DATA101] [Dataset]

2025. "Reprocessed CAMEX-3 (1998) EDOP Radar Dataset.", NASA GHRC, [http://dx.doi.org/10.5067/CAMEX3/EDOP/DATA101] [Dataset]

2025. "NASA WHyMSIE CRS Airborne Doppler Radar Dataset.", NASA GHRC, [Full Text] [Dataset]

2023. "NASA IMPACTS 2023 HIWRAP Radar Data.", NASA GHRC, [http://dx.doi.org/10.5067/IMPACTS/HIWRAP/DATA101] [Dataset]

2023. "NASA IMPACTS 2023 EXRAD Radar Data.", NASA GHRC, [http://dx.doi.org/10.5067/IMPACTS/EXRAD/DATA101] [Dataset]

2023. "NASA IMPACTS 2023 CRS Radar Data.", NASA GHRC, [http://dx.doi.org/10.5067/IMPACTS/CRS/DATA101] [Dataset]

Contact Us

For general inquiries about the Sciences and Exploration Directorate.

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Project Support Specialist

301-286-6066 jocelyn.m.lynch@nasa.gov
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Project Support Specialist

301-286-6066 ellie.jeffries@nasa.gov
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