High Heat Index and Timing of Fertilizing

[Farmette]

High Heat Index (very hot and humid) of over 100 expected in our area Thurs and Friday. I am anticipating alot of blossom drop, so I was thinking it would be a good idea to give my tomatoes some Texas Tomato Food to encourage blossoming after the wave. For sure, I will keep them hydrated, but the question is: Is it better to feed them now or wait til after the wave has passed? Or maybe timing doesn't matter...