I don't think it's quite as wet here as you might imagine from listening to weather forecasts. What follows is NOT definitive advice on the wisdom (or otherwise) of your proposed trips this weekend - but it may help a bit. (It'd be good if others commented, either to agree or disagree with my last paragraph below!)
If you want to get a pretty good idea of conditions there are various useful online sources. The Environment Agency website has the facility to search through real time hydrographs of all the major rivers (including the Ribble, which is probably most useful for the Alum Pot system). From these you can tell if the flow is increasing or dedreasing. The "Settle Hydro" (Google to find) allows you to see a webcam picture of the wier on the Ribble at Settle - this is incredibly useful. The Cave Diving Group's "VisBot" (see website) gives rainfall amounts at strategic places over the last 7 days - the most relevant to your query are those posted by Richard Kavanagh (who, incidentally, is a former member of your own club).
The water goes up quick and down quick in Long Churn. It is VERY dangerous in wet conditions - tragically, there have been fatalities due to flooding. However, my interpretation of the forecasts for Saturday (and it's early days as I type - check this yourself nearer the time obviously) is that by then the water may be on its way down. This means you might be OK - depending on timing and more up to date forecasts of course. It's definitely a case of err on the safe side but don't completely rule out a trip in there on Saturday. Can't comment on Sunday though; it's too far ahead. Also factor in that, with inexperienced people, even more care than normal with the weather is advisable. If in any doubt, it's probably safest to abandon the trip.
