Severe weather before Open Source Summit
This week, we have some rather severe weather predicted for east of Czechia. ("In the period from Thursday 12. 9. to Sunday 15. 9. (total for four days) are expected extreme precipitation, mostly above 300 mm.") Austria should not be affected as badly, and it is all predictions for now, but if you plan to travel through Czechia, well... there may be a little too much water around.
The water will not simply disappear, so flooding will move downstream in the days after that.
https://meteoalarm.org/en/live/warning/406902d3-4c95-4b61-908a-7ee4523199f6/97f6f345-872b-4e99-be62-+93e84d4eee0c?t=day3#list
If you plan to travel by land, you may want to check weather / flood status before the trip. Travel by boat is not recommended :-).