John Gill Commentary Genesis 41:31

"and the plenty shall not be known in the land by reason of that famine which followeth; for it shall be very grievous." — Genesis 41:31 (ASV)

And the plenty shall not be known in the land, by reason of
that famine following
That is, before it would be over; otherwise the former plenty was in some measure known by the stores of provisions laid up in the seven years of it, and which were brought forth when the famine became very pressing; but by that time, and before the seven years of it were ended, there were no traces of the foregoing plenty to be observed: for it [shall be] very grievous ;
as it was both in Egypt and in all the countries round about.