Yep, Met observers on site saying general visibility at Krakow airport is 200 meters in freezing fog at 1000 UTC, but the real clincher for operations is the automated system that measures visibility along the runway - that’s giving 375 metres…
I think Ryanair crews these days are all weather/low visibility qualified so the problem might be with the set up at Krakow. I Haven’t got the latest documents for the airport but unless they have a better than a basic Category standard instrument landing system 375 metres quite possibly puts it well below limits for anyone, all weather qualified or not, even attempting an approach…
Forecast shows changes of brief periods of visibility improvements throughout the PM but nothing spectacular.
As far as Flightradar data goes the system doesn’t have access AFAIK to live flight plan data and can get easily confused if flights/flight numbers don’t go to plan, that might explain why Alicante has entered the equation.