The gdi

Forecasting Tool developed by 
José Manuel Gálvez  and  Michel Davison

the galvez-davison index (GDI)

The GDI  (Gálvez and Davison, 2016)  is a stability index developed by José Manuel Gálvez and Michel Davison, to evaluate the potential for convection development in the tropics and subtropics. It helps to discern whether the environment is favorable to host shallow convection, deep convection, or deep convection with the potential for excessive rainfall.  It also aids with the detection of numerous impactful weather systems.  The GDI has applications in numerous areas, most notably on aviation and on the forecasting of excessive rainfall.  These benefits have led to its implementation and routine application in numerous National Weather Services and other institutions around the world.

GDI Applications

Excessive Rainfall Forecasting.
Planning of Flight Routes in Aviation.
Impactful Weather System Detection.
Tropical Cyclone Structure Analysis.
Tropical Wave tracking.
Detection of environments for the formation of Mesoscale Convective Systems (MCS).

operational gdi online

Current GFS Model GDI Output is available at NOAA's Weather Prediction Center Website, the official GDI site (click).

Other institutions have operational versions of the GDI coded for internal use (e.g. INMET, the Weather Service of Brazil). Additional resources available online are listed in the following section.

 The 2016 GDI manuscript contains information about the GDI and equations to code it.

GDI MANUSCRIPT: Galvez and Davison, 2016: The Gálvez-Davison Index for Tropical Convection

OpERATIONAL GDI online Resources around the world

mexico NWS gdi forecasts

The Weather Service of Mexico (Servicio Nacional de Meteorología, SMN) hosts an operational GDI website with current GFS model GDI forecasts for Mexico.

weather.us gdi forecasts

The private company weather.us hosts operational GDI forecasts for the entire world using output from different numerical weather prediction models. This includes models such as the ECMWF, GEM, RDPF, GFS, etc.

meteorologix.com gdi forecasts

The private company meteorologix.com hosts operational GDI forecasts for the entire world coded in different models.

Kachelmannwetter gdi forecasts

Operational GDI forecasts are available online on the Kachelmannwetter.com Luxembourg private company's website, using different models and covering the entire world.

GDI STUDIES and training resources

publications USING THe GDI

Douglas Vieira da Silva, Luiz do Vale Silva Thiago, Ricardo Camargo and Doris Veleda, 2025: Influence of sea stratification and troposphere stability over the coastal squall lines of eastern Amazon. Volume 63, 8.

Paul Miller and Craig Ramseyer, 2024:The Relationship Between the Saharan Air Layer, Convective Environmental Conditions, and Precipitation in Puerto Rico. JGT Atmospheres. Volume 129, Issue 1. https://doi.org/10.1029/2023JD039681

José Francisco León-Cruz, Ernesto Caetano, Christian Dominguez, Jorge Cortés-Ramos, Juan M. Méndez-Pérez and Alejandro Jaramillo, 2024: Spatiotemporal Characterization of Instability Indices Associated with Thunderstorms in Mexico. Wiley. Advances in Meteorology. Volume 2024, Article ID 4478159, 17 pages. https://doi.org/10.1155/2024/4478159

José León-Cruz, Jorge Cortés-Ramos and Álvarez-Báez, Christian, 2024: Evaluación del Índice Gálvez-Davison para tormentas eléctricas en el centro de México. 18. 42-53. 

Pedro M. González-Jardines, Aleida Rosquete-Estévez, Maibys Sierra-Lorenzo, Arnoldo Bezanilla-Morlot, 2024: A Hybrid Model Evaluation Based on PCA Regression Schemes Applied to Seasonal Precipitation Forecast10.4236/acs.2024.143021

Kathrin Alber, Liming Zhou, Paul E. Roundy, Stephen L. Solimine, 2023: Influence of the Madden-Julian Oscillation on the diurnal cycles of convection and precipitation over the Congo Basin, Atmospheric Research, Volume 294, 2023, 106967, ISSN 0169-8095, https://doi.org/10.1016/j.atmosres.2023.106967

Pedro M. González-Jardines, Maibys Sierra-Lorenzo, Adrián L. Ferrer-Hernández, Arnoldo Bezanilla-Morlot, 2023: Evaluation of Candidate Predictors for Seasonal Precipitation Forecasting. Atmospheric and Climate Sciences. Vol.13 DOI: 10.4236/acs.2023.134031 

Tahimy Fuentes-Alvarez, Pedro M. González-Jardines, José C. Fernández-Alvarez, Laura de la Torre and Juan A. Añel, 2023: Analysis of the Gálvez–Davison Index for the Forecasting Formation and Evolution of Convective Clouds in the Tropics: Western Cuba. Climate 2023, 11(10), 209; https://doi.org/10.3390/cli11100209

Equisha Glenn, Thomas M. Smith, Jose M. Gálvez, Michel Davison, Keneshia Hibbert and Jorge E. González, 2021: Tropical Convection in the Caribbean and Surrounding Region during a Regional, Warming Sea-Surface Temperature Period, 1982–2020. Hydrology 2021, 8(2), 56; https://doi.org/10.3390/hydrology8020056

Paul Miller and Jill Trepanier, 2021: Predicting the Gulf of Mexico Hurricane Season With 500-hPa Temperature. Geophysical Research Letters.

P. W. Miller, M. Williams, T. Mote, 2021: Modeled atmosphericoptical and thermodynamicresponses to an exceptional trans-Atlantic dust outbreak. Journal ofGeophysical Research: Atmospheres,126, e2020JD032909. https://doi.org/10.1029/2020JD032909

Kathrin Alber, Ajay Raghavendra, Liming Zhou, Yan Jiang, Heather S. Sussman & Stephen L. Solimine , 2021: Analyzing intensifying thunderstorms over the Congo Basin using the Gálvez-Davison index from 1983–2018. Volume 56, pages 949–967.

Paul Miller, Thomas Mote and Craig Ramseyer, 2019: An Empirical Study of the Relationship between Seasonal Precipitation and Thermodynamic Environment in Puerto Rico. Weather and Forecasting. 34, 277-288.

Paul Miller, A. Kumar, T. L. Mote, F. D. S. Moraes, and D. R. Mishra, 2019: Persistent Hydrological Consequences of Hurricane Maria in Puerto Rico. Geophysical Research Letters. Letter 10.1029/2018GL081591. 10pps.

William Hanson, 2019: Analysis of the Galvez-Davison Index for Convective Forecasts Over Africa Using the GALWEM. AIR FORCE INSTITUTE OF TECHNOLOGY WRIGHT-PATTERSON AFB OH WRIGHT-PATTERSON AFB, Technical Report. 173pp.

Gabriel Donndelinger, 2018: A New Analysis of the Gálvez-Davison Index for Convective Forecasts in Northern Africa. Thesis. Theses and Dissertations. 1746. https://scholar.afit.edu/etd/1746

Thomas L. Mote, Craig A. Ramseyer, Paul W. Miller, 2017: The Saharan Air Layer as an Early Rainfall Season Suppressant in the Eastern Caribbean: The 2015 Puerto Rico Drought. JGR Atmospheres. Volume 122. Issue 20. https://doi.org/10.1002/2017JD026911

GDI Training module at comet-meted

COMET-Meted hosts a training module on applications of the GDI, developed in 2025. Demonstrates how the GDI often beats other indices and satellite tools to detect areas where different types of convection occur.

Use of the Gálvez-Davison Index in operations at American Samoa

This blog by Scott Lindstrom summarizes the use of the GDI in operations in American Samoa.

ICAO-NOAA stability index ppt

A powerpoint presentation prepared by Jose Manuel Galvez in representation of Axiom/NOAA for a workshop prepared and conducted at the International Civil Aviation Organization (ICAO) office in Mexico City (2023) is hosted on their website. Partially based on WPC International Desks presentations.

Applications on American SAMoa

This blog by Scott Lindstrom summarizes the use of the GDI in conjunction with the K-index to analyze and forecast the potential for deep convection in American Samoa (Source: CIMMS/University of Wisconsin)