This is a customized version of Groupboard Designer which was developed for NOAA's Collaborative Convective Forecast Product. The Groupboard software has been used by NOAA's Aviation Weather Center since 1999 to allow weather forecasters in different countries to draw comments and changes onto the forecasts, and discuss the forecasts using a chat window. We updated the software in 2013 to use html5 instead of java.
The demo below is not the real system, so feel free to draw on top of the forecasts.
Use the PREV and NEXT buttons to move between forecasts. You can then save your marked up forecast by clicking SAVE. If other users are connected to the board at the same time, you will be able to chat to them.