I was part of the Bureau of Meteorology's forecasting team for the 2000 Olympics. One story that didn't get out was how worried we were with our 'fine and beaut' forecast for the opening ceremony. We had gone hard and early with 'promising' great weather for that evening. 1/
2/ The closer we got to the day the more certain we were that a southerly wind change would move through Sydney early evening on the day. The experienced local forecasters said that if the change had a depth of over 1km there would be a chance of drizzle.
3/ The computer models indicated that the change would have a depth of 'about' 1km. We held firm with the forecast but we were worried. I worked the evening of the opening ceremony. Cloud came in with the change on dusk and in the dimming light the cloud looked dark.