The West Yorkshire club are without 11 first-team players ahead of hosting the side that are currently sitting second in Super League.
Moreover, and especially bizarrely after the hectic Easter period, Warrington are selecting from almost full-strength.
Powell, who is set to give a debut to former Melbourne Storm centre Cheyse Blair, said: “They’ve got lots of good players and I think they’ve only got one injury.
“Warrington have a good flow about them. They have had a couple of tough results, but are back on form in their last two games, playing pretty well.
“We know they are going to come after us and challenge us and we have to play as well as we can.
“We’ve got to get under their skin, get after them and see where that takes us.
“We had a real big challenge last week and handled that pretty well. This is another big challenge for us. We need to be outstanding to win the game.”
Castleford have slipped to fifth having fought hard but lost 6-4 at champions Wigan Warriors last Saturday and falling 37-16 at Catalans Dragons on Easter Monday.
“We’ve just got to ride through this tough period we’re having at the moment,” insisted Powell, whose side also lost 24-10 at Warrington in March.
“I think we’re doing a great job with it; the players are really digging in.
“We’ve had a tough Easter, crazy in terms of what we’ve been given there and they need to get a grip of that, the Rugby (Football) League; it’s no surprise Catalans have won their last six home games on Easter Monday.
“(But) character comes from going through tough situations and I think we’re showing a lot.
“I’ve seen plenty of teams completely fold under the kind of injury list we’ve got – and we’re not doing that.
“We’re hanging tough. That shows there’s good leadership within the group and also that the players coming in are doing a good job for us. The key is we have to start winning games again.”