The IAA were most definitely using the right chart for 06:00 this morning which clearly had a black area across Northern Ireland sufficient to cause the closures seen this morning. The 12:00 forecast issued at the same time showed no black areas so most people were hopeful that the closures would be short.
Whether or not there really was a high concentration as per the forecast is a different matter but there was ample time to arrange flights to sample it so hopefully by now somebody knows how accurate the forecast was.