This website provides links to HYSPLIT modeling software (part of the Real-time Environmental Applications and Display sYstem-READY) that forecasts volcanic ash concentrations. Forecasts may be manipulated to various specifics. The website also provides links to compute archived volcanic ash concentrations, previous model results and links to other volcano-related websites.
Publications using HYSPLIT results, maps or other READY products provided by NOAA ARL are requested to include an acknowledgement of, and citation to, the NOAA Air Resources Laboratory.
National Oceanic and Atmospheric Administration (NOAA): http://www.noaa.gov/