The Mac is in good shape. If you encounter thunderstorms look for silty water on the lower part. We still have some March browns and the PMD's start in the later afternoon to appear. Watch for hatches of Gronnoms for the Mac is a real Caddisfly stream. If the fish don't feed on top start making it a nymping affair. I had good results with a #12 March Borwn and a Copper John #14-16. The Redside trout likes big water and is a feisty fish often hard to land. 
Another technique is if you tie on a Soft Hackle and present it with a wet-fly swing.  I saw a few Golden stoneflies and these become more prolific as we go further into may, here is were you can do well with the nymphs.
Later in the month, green drakes may become important. Watch for small hatches and start using nymphs. Those big duns are teh double wopper for trouts. Tight lines!