Introduction -- Rainfall and Evaporation Climatologies -- Water Vapour and Clouds -- Radiation, Dust, Sunshine Duration, Vegetation and Soil Water -- Pressure, Temperature, Humidity and Wind at the Surface -- Upper Air Wind, Mass and Humidity Fields -- Eulerian Perspective on the Wind, Circulation and Dynamics -- Lagrangian Perspective on the Circulation -- Summary Schematics of the January and July West African Monsoon System -- Acknowledgements -- Appendix: Acronyms -- Notes -- References -- Scientific Background -- Introduction -- Continental-scale Synoptic Features -- Saharan Heat Low -- Intertropical Discontinuity or Intertropical Front -- African Easterly Jet -- African Easterly Waves -- Background -- Observed Synoptic Structure of African Easterly Waves, Analyses and Statistical Composites -- African Easterly Wave Structure -- African Easterly Wave Genesis -- African Easterly Wave Dynamics and Evolution -- Relationship with Deep Convection -- Downstream Transformation -- Mid-latitude Troughs and Upper-level Troughs -- Extratropical Dry Air Intrusions -- Guinea Coast Systems -- Guinea Coast Cloud and Rainfall -- Little Dry Season -- Synoptic-scale Land-surface Feedbacks -- Operational Methods and Canonical Synoptic Patterns -- Synoptic Fields and Main Inferences -- African Easterly Wave Case Studies and Canonical Structures -- Archetypal African Easterly Wave Event: Case Study CS02, 12-16 August 2012 -- African Easterly Wave Breaking Events -- Coastal Development of African Easterly Waves -- Dry-season Thunderstorms in West Africa -- Acknowledgements -- Appendix: Acronyms -- Notes -- References -- Scientific Background -- Introduction -- Is Convection Different over Africa? -- Interaction Between Convection and the Larger Scale Flow -- Aims of this Chapter -- Processes and Factors Governing Convection -- Convective Updraughts -- Downdraughts, Downdraught Available Convective Potential Energy and Density Currents -- Wind Shear -- Discussion -- Organisation of Deep Convection -- Different Types of Organisation -- Squall-line Conceptual Model -- Climatology and Classification of Mesoscale Convective Systems -- Life Cycle and Diurnal Cycle -- Triggering -- Diurnal Cycle -- Dissipation -- Operational Methods -- Life Cycle of Convection on 12-16 August 2012 (CS02) -- MCS1 -- MCS2 -- MCS3 -- CS1 -- CS2 -- Suppressed Convection -- Cold Pool Case Study, 27 September 2014 (CS14) -- Forecasting Areas of Storm Initiation or Suppression -- Synoptic Conditions and Stability -- History of Recent Storms -- Use of Numerical Weather Prediction to Forecast Convective Initiation -- Forecasting Storm Types -- Organisation, Longevity, Speed and Direction -- Weather Phenomena -- Forecasting Suppression of Convection -- Acknowledgements -- Appendix: Acronyms -- Notes -- References -- Scientific Background -- Introduction -- Surface Energy Balance and the Atmospheric Surface Layer -- Surface Energy Balance Principles -- Surface-layer Winds -- Surface Energy Balance over West African Climatic Zones -- Variation of Surface Energy Balance and Surface Temperatures in Response to Physical Processes -- Boundary Layer over West Africa: Diurnal Cycle -- Daytime Convective Boundary Layer -- Night-time Planetary Boundary Layer -- Fog Formation -- Marine Planetary Boundary Layer -- Local Winds: Mesoscale Variability and Circulations -- Coherent Structures in the Winds: Convergence Lines and Gravity Currents -- Sea Breeze and the Land Breeze -- Topographically Forced Winds -- Local Winds and Convergence Associated with Soil Moisture and Vegetation Boundaries -- Trapped Waves, Bores and Solitary Waves -- Convective Rainfall Distribution on the Local Scale -- Cumulus Congestus Clouds -- Land Surface Controls on Rainfall: Soil Moisture and Vegetation -- Marine Weather -- Operational Methods -- Forecasting of Maximum and Minimum Temperatures (Tx, Tn) -- Statistically Based Forecasts -- Physical Methods Based on Sounding Data -- Integration with Numerical Weather Prediction Data -- Physical Processes Influencing Daily Temperatures -- Visibility -- Basic Principles of Visibility Forecasting -- Fog Forecasting -- Forecasting Wind Shear and Turbulence -- Forecasting Land, Sea and Lake Breezes -- Marine Forecasting -- Winds over the Sea -- Ocean Waves -- Visibility over the Sea -- Marine Services -- Forecasts/Warnings -- Routeing of Ships -- Acknowledgements -- Appendix: Acronyms -- Notes -- References -- Scientific Background -- Dust Cycle -- Emission -- Transport -- Wet and Dry Deposition -- Meteorological Systems -- Climatologies -- Interactions with Weather and Climate -- Direct Radiative Effect -- Impact on Atmospheric Stability -- Impact on Cloud Microphysics -- Fertilisations of Ecosystems by Dust -- Operational Methods -- Introduction and Structure -- Data -- Surface Station Data -- Surface and Pressure-level Charts -- Remote Sensing -- Numerical Model Predictions of Dust -- Practical Guidelines for Forecasters -- Introduction -- Forecasting Harmattan Dust Haze -- Forecasting Convective Dust Storms -- Case Study Examples Online -- Appendix: Acronyms -- Notes -- References -- Scientific Background -- Introduction -- Nowcast Process -- Convective Weather Outlook -- Conceptual Models and Climatology -- Stability Analyses -- Storm Type -- Extrapolation of Existing Storms -- Nowcasting Storm Initiation and Evolution -- Operational Methods for Nowcasting Severe Weather -- Thunderstorms, Hail and Flash Floods -- Procedure for Nowcasting Thunderstorms, Hail and Flash Floods -- Wind Shear -- Procedure for Nowcasting Wind Shear -- Lightning -- Procedure for Nowcasting Lightning -- Appendix A: Acronyms -- Appendix B: Checklist for Improving Operational Nowcasting Capability -- Appendix C -- Appendix D: Online Web Sites Containing Weather-related Training Materials -- Note -- References -- Scientific Background -- Introduction -- Data -- Precipitation -- Sea Surface Temperature -- Outgoing Longwave Radiation -- Brightness Temperature -- Reanalysis -- Detection of the Main Modes of Subseasonal Variability of Convection -- Convectively Coupled Equatorial Waves -- Kelvin Waves -- Equatorial Rossby Waves -- Mixed Rossby-Gravity Waves -- Other Convectively Coupled Signals and Links with Equatorial Waves -- Signals.

Between 10 and 25 Days -- Periodicities Between 25 and 90 Days and the Madden-Julian Oscillation -- Mechanisms for Dry- and Wet-spell Frequency -- Onset of the Monsoon and Rainfall -- Detection -- Mechanisms -- Applications -- Summary and Outlook -- Operational Methods -- Prediction Tools -- Madden-Julian Oscillation Predictions -- Prediction of Regional Climate Anomalies -- Guidelines for Operational Forecasting -- State of the Madden-Julian Oscillation -- Consensus Outlooks -- Forecast Verifications -- Acknowledgements -- Appendix: Acronyms -- Note -- References -- Scientific Background -- Introduction -- Sea Surface Temperature Teleconnections -- Statistical Forecasts -- Methods -- Representation of Predictors: Sea Surface Temperature Empirical Orthogonal Function Predictors -- Representation of Predictands -- Assessment of Statistical Methods -- Performance over 1996-2009 -- Dynamical Forecasts -- Performance over 1996-2009 -- Correction of Systematic Errors in Models -- Future Models: Potential for Improving Seasonal Forecasts -- Long-lead Predictability -- Combined Forecasts -- Performance over 1996-2009 -- Other Variables and Seasons -- Prediction of Outflow from Lake Volta -- Prediction of Meningococcal Meningitis in the West Africa Dry Season -- Applying Seasonal Forecasts to Assist Agriculture in Senegal -- Operational Methods.

International Seasonal Forecast web sites: Sources of Information -- World Meteorological Organization Lead Centre Multimodel Ensemble web site -- Long-range Forecast Verifications -- UK Met Office web site -- ECMWF/EUROSIP web site -- NOAA/NCEP web site -- International Research Institute for Climate and Society Seasonal Forecast web site -- African Center of Meteorological Application for Development web site -- Consensus Forecasts -- PRESAO Process -- Assessment of PRESAO Forecasts 1998-2007 -- Software and Tools -- Climate Predictability Tool -- International Research Institute for Climate and Society Data Library -- KNMI Climate Explorer -- NOAA Earth System Research Laboratory Interactive web site -- Other web sites Including Forecast Applications -- FEWS NET -- AGRHYMET, Niger -- Hints and Recommendations -- Appendix A: Acronyms -- Appendix B: Empirical Orthogonal Functions -- Note -- References -- Scientific Background -- Global Satellite Observing System -- Orbital Geometry -- Advantages and Limitations of Geosynchronous and Low-earth-orbit Satellites -- Scanning and Viewing Geometry -- Scientific Basis of Remote Sensing -- Electromagnetic Spectrum -- Radiance and Blackbody Radiation -- Radiative Transfer -- Reflectance -- Passive and Active Remote Sensing -- Spectral Bands or Channels -- Visible and Infrared Channels -- Microwave Channels -- Multispectral Analysis: Visualised Products -- Classification Using Individual Channels -- Differencing or Ratio of Two Channels -- Quantitative Feature Extraction -- RGB Products -- Blended or 'Sandwich' Image Products -- Satellite Retrieval of Meteorological Parameters -- Water Vapour -- Vertical Structure of Temperature, Humidity and Winds -- Clouds -- Precipitation -- Dust -- Fire, Smoke and Haze -- Volcanic Ash -- Lightning -- Surface Wetness and Vegetation -- Ocean Surface Winds -- Weather Radar -- Weather Radar Basics -- Ground and Satellite Weather Radar Products -- Wind Profilers -- Operational Methods -- Platforms and Sensors -- Geostationary Satellites and Sensors -- Low-earth-orbiting Satellites -- Satellite Operational Analysis Tools and Products -- Radar Operational Analysis Tools -- Large-scale Feature Identification -- Intertropical Discontinuity and Intertropical Convergence Zone -- Subseasonal Circulations: Madden-Julian Oscillation, Equatorial Waves -- Synoptic Systems -- Mesoscale and Local-scale Analysis -- Mesoscale Circulations -- Mesoscale Convective Systems -- Dust and Sand Storms -- Convective Cells, Outflow Boundaries, Cloud Lines -- Fog and Low Stratus -- Satellite Soundings -- Winds -- Aviation Hazards -- Marine Analysis -- Sources of Satellite Products -- Case Study, Presentations and Other Resources -- Radar and Satellite Analysis -- Mesoscale Convective Systems and an African Easterly Wave -- Tropical Cyclone, Undular Bore and Other Cloud Systems -- Presentations -- Education and Training -- Appendix: Acronyms -- References -- Scientific Background -- Introduction -- Deterministic Numerical Weather Prediction Systems -- Observations -- Data Assimilation -- Global and Regional Numerical Weather Prediction Models -- Convective-scale Models -- Model Output Statistics -- Ensemble Prediction and Atmospheric Predictability -- Summary and Future Capability -- Operational Numerical Weather Prediction over Africa -- Current Capability of Deterministic Numerical Weather Prediction Forecasts -- Precipitation and Moisture Budget in Numerical Weather Prediction Models and Analyses -- Near-surface Temperatures and Humidities -- Low-level Monsoon Flow and Saharan Heat Low -- African Easterly Jet -- African Easterly Waves -- Predicting Severe Weather and Modelling Uncertainty -- Ensemble Forecasts from Deterministic Predictions -- World Meteorological Organization Severe Weather Forecast Demonstration Project -- Convective (Kilometre)-scale Modelling -- Acknowledgements -- Appendix: Acronyms -- Notes -- References -- Introduction -- Intertropical Discontinuity/Intertropical Front, or Intertropical Boundary in Ghana -- Main Characteristics -- Drawing Rules -- Specific Cases -- Heat Low or Thermal Depression -- Main Characteristics -- Drawing Rules -- Subtropical Jet -- Features Associated with Mid-latitudes -- Mid-level Dry Air -- Main Characteristics -- Drawing Rules -- Tropical Easterly Jet -- Main Characteristics -- Drawing Rules -- African Easterly Jet -- Main Characteristics -- Drawing Rules -- African Easterly Waves and Cyclonic Vortices -- Main Characteristics -- Drawing Rules -- African Monsoon Layer and the Monsoon Trough -- Main Characteristics -- Drawing Rules -- Dust or Sand -- Convection -- Analysis of the Convective Activity -- Forecast Rules and Required Diagnostics for Convection -- Appendix: Acronyms -- Notes -- References.