This is the normal way to talk about changes in deficits and surpluses in English, and it’s not ambiguous, although it may look that way initially. In everyday speech, a “deficit” already means a shortfall or a negative amount. When we say a “surging deficit,” we mean the size of that shortfall is increasing. We generally treat deficits as only positive or zero (never negative), and if it flips, we call it a “surplus” instead.