If your horse isn't being boarded where they supply the feed, you better start stocking up. We're in our 2nd year of drought here in OK and I know it's not AS bad in the NE, it's still not good and you may find you run short before winter's over. I have several hundred small bales stored in my feed barn already and over 100 round bales to get us through til next haying season. I hope I've stored up enough!
As for grain, a lot will depend on how much/type of hay you can get. If you run short of hay and have a Purina dealer near you see if you can get Omolene 400, it's a complete feed and will help you to stretch out the hay. Otherwise, I like Strategy GX, I find it's economical and effective.
As long as your horse has grass in front of him, whether off a bale or on the ground, he'll be fine only getting concentrate once/day. Make sure you give him a free choice of salt too, so he'll stay hydrated, especially while we're having this 105-110 F days.