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Home » Who We Are » Organization » Leadership



Jennifer Mahoney is the Director of the NOAA Earth System Research Laboratories/Global Systems Laboratory (ESRL/GSL). She leads a staff of nearly 200 meteorologists, software engineers, and support staff dedicated to “making forecasts better.” GSL research provides the NOAA National Weather Service (NWS) and the public with rapidly-updating environmental models, state-of-the-art decision support tools, innovative visualization systems, and high-performance computing technology to support commerce and a weather-ready nation. GSL’s most recognizable accomplishments include NOAA’s High-Resolution Rapid Refresh high-impact weather prediction model used in NWS operations, the Science on a Sphere®, a six-foot diameter animated globe used to display Earth science datasets seen by nearly 50 million people each year, and forecast tools used in 120 NWS offices for predicting the weather and supporting impact-based weather decisions.

Jennifer holds a Master’s degree in Atmospheric Science from Colorado State University and a Bachelor of Arts Degree in Meteorology from the University of Northern Colorado. Jennifer is a member of the American Meteorological Society (AMS) and is serving on the Commission on the Weather, Water and Climate Enterprise Steering Committee as well as on the board for the AMS Committee on Environmental Information Processing Techniques.

Jennifer has served as GSL Deputy Director, the Lead for the Federal Aviation Administration’s (FAA) Quality Assessment Product Development Team, and as the Chief of GSD’s Forecast Impact and Quality Assessment Section. In 2017 and 2003, NOAA’S OAR (Oceanic and Atmospheric Research) selected Jennifer as the NOAA Research Employee of the Year for Leadership. Jennifer’s research expertise is in the areas of atmospheric science for aviation and winter weather, impact-based verification and assessment, and decision support strategies for forecast systems.

DaNa L. Carlis, Ph.D. is a meteorologist and serves as the Deputy Director at GSL since September 2020. He comes to GSL from the Weather Program Office (WPO) where he established the Earth Prediction Innovation Center (EPIC) Program. DaNa enjoys working between science, policy, and society to ensure better products and services for the American people. While spending over 18 years at NOAA, he began his career as a graduate student in NOAA’s Office of Education Educational Partnership Program (EPP). Soon after joining NOAA, DaNa was stationed in Honolulu, Hawaii for 3 years of intensive weather research, numerical model development, and dissertation writing. He’s held positions at the National Weather Service Environmental Modeling Center as a research meteorologist developing the world’s mostly widely used weather forecast model (Global Forecast System Model), as a policy advisor to NOAA’s Chief Scientist and NOAA’s Assistant Secretary of Environmental Observations and Prediction. In 2016, he wrote a children’s book titled “MIT: Meteorologist in Training.”

Melissa (Missy) Petty serves as the Associate Director for Administration in the Global Systems Laboratory (GSL). Before joining GSL’s Office of the Director, Missy worked for the Cooperative Institute for Research in the Atmosphere (CIRA) as a GSL affiliate, serving as Chief of GSL’s Forecast Impact and Quality Assessment Section (FIQAS). In this role, she worked closely with the National Weather Service, Federal Aviation Administration, and other stakeholders to advance operationally-relevant forecast evaluation techniques and technologies, leading a multidisciplinary team of scientists and software engineers to perform formal, in-depth product assessments and develop related evaluation tools and decision support systems.

Missy’s career began as a software engineer at the National Center for Atmospheric Research, where she was involved in the implementation of various forecast systems, including aviation weather forecasts for turbulence and ceiling and visibility, and a statistical forecast system that is used in multiple market segments. This was followed by a period in the private sector working for SAP, one of the market leaders in enterprise application software. She returned to the atmospheric science community as a software engineer in FIQAS, developing automated data processing and analysis systems to support forecast verification.

Missy holds a Ph.D. in Mathematics from the University of Colorado, Boulder, and a B.A. in Mathematics from Millsaps College in Jackson, MS.

GRANVILLE.Penny.2016.10.05.jpgPenny Granville has been GSL’s Administrative Officer since 2005. She manages the administrative staff working on Facility Access, Deemed Exports, and Property accountability. She coordinates the labs budget execution and aids in the budget formulation processes. Penny is the HR representative, processing personnel actions for Federal, CI and Contract staff. She is GSL’s Financial Management Center (FMC) serving as the focal point for all procurement and acquisitions matters monitoring all transactions such as purchase orders, credit card purchases, reimbursable agreements, travel, etc. Penny ensures GSL processes and staff are in compliance with NOAA, DOC and OAR guidelines, policies, and procedures.
ALEXANDER.Curtis.2017.11.07.IMG_0004.jpegCurtis Alexander is the Chief of the Assimilation, Scientific Computing, Evaluation and Novel Division (ASCEND) and works on techniques to assimilate all types of weather observations, including radar and satellite data, into weather prediction models. These assimilation techniques are applied to regional models, but some applications are moving towards global model data assimilation.
GRELL.Georg.2017.06.09.jpgGeorg Grell is Chief of the Earth Prediction Advancement Division (EPAD). EPAD works to improve and apply numerical weather prediction models in scales ranging from local to global and from a few hours to seasonal. We develop of state-of-the-art atmospheric physical parameterizations, improve the representation of processes that impact atmospheric composition and their interaction with physical processes, and include all earth domains (atmosphere, land, biosphere, ocean, and sea ice) in our modeling systems. Applications range from forecast impacts of wildfires on air quality and weather conditions to prediction of increased likelihood of excessive precipitation in the lower Mississippi River basin during week 3. We use common infrastructures to collaborate with the broad scientific community with the goal of augmenting scientific understanding and improving NOAA predictions.
Daniel Nietfeld is Chief of the Weather Informatics and Decision Support (WIDS) Division. WIDS develops state-of-the-art environmental forecast, warning, decision support, and visualization capabilities to provide scientifically robust forecast tools, concepts, and analyses that support decision-making processes affected by the weather, water, and climate. We do this by coupling the latest advancements in machine learning, data visualization, social science research, and computer science/engineering with cutting-edge atmospheric and environmental science to empower forecasters and decision-makers with the best information they need. Our partners and customers are made up of numerous federal, state, and local government agencies that deal with operational weather and environmental issues; this includes the National Weather Service (NWS), the Federal and local Land Agencies that deal with wildfires, the Department of Defense, the Department of Transportation, the emergency management community, and international partners such as Australia and Taiwan. Through a partnership with NOAA's Office of Education and the Science on a Sphere (SOS) Team, we help NOAA communicate its science and develop new ways of interacting with our data. In addition, the WIDS Division hosts the NOAA Fire Weather Testbed, which leverages social science and verification expertise to enable research to operations (R2O) feedback between the creators of fire weather tools and operational decision makers.
Scott Nahman is Chief of GSL’s Information Technology Services Division and the Senior IT Manager. He manages a multi-million-dollar budget and provides leadership and supervision to 30 technical experts in support of the world-class research of GSL. Scott also serves as the Office of Atmospheric Research representative on the NOAA Federal Data Center Optimization Initiative. GSL is one of NOAA’s three sites that host research and development high-performance computing systems shared by the entire NOAA community. Scott Nahman graduated from the University of Colorado Naval ROTC program and served aboard the USS Germantown as the Electronics Material Officer and Electronic Warfare Officer. He began his NOAA career as a contractor working for the Wind Profiler Program in the Forecast Systems Laboratory as a Logistics Engineer in 1997. Scott transitioned to Federal employment in 2001 as the (IT) Facilities Manager within the Information and Technology Services branch of the Global Systems Division. During this time Scott has been responsible for the construction of 3,200 square feet of raised floor data center space, and the upgrade of an additional 4,350 square feet of IT infrastructure space at the David Skaggs Research Center in Boulder Colorado.