01 Consider readily available forecasting tools The Air Quality (AQ) Forecasting Guidance begins at Stage 2. At Stage 1, it is not recommended you start your own Forecasting activities; instead, prioritize establishing foundational systems under the other AQMx Guidance areas. Build reliable forecasting capacity by first establishing routine monitoring of data, meteorological information, institutional coordination, and basic communication systems before conducting air quality forecasting. Nevertheless, if capacity is available, it would be beneficial for nascent teams to begin familiarizing themselves with air quality science and existing forecasting tools and methods, especially those focused on large-scale air quality events such as forest and agricultural fires (biomass burning) or dust storms, as described in more detail in Stage 2. Early coordination with Monitoring, Source Attribution, and Emissions Inventory should also help ensure that monitoring, meteorological, emissions, and chemical-speciation data collected at this stage can eventually support both forecast development and analysis of the sources contributing to observed pollution events. This guidance document was prepared by Cynthia A. Randles (Randles Ozkul Consulting) under the overall oversight of the Climate and Clean Air Coalition Secretariat. The CCAC wishes to thank Westervelt (Associate Research Professor, Lamont-Doherty Earth Observatory (LDEO), Columbia University) and AQMx TAG Forecasting expert, as well as Beatriz Cardenas (One Atmosphere Director, WRI Mexico) and Chair of the AQMx Technical Advisory Group, for their valuable feedback.