"portends that" is a correct and usable phrase in written English.
You can use it when you want to express that something is a warning or sign of a future event or outcome. Example: The dark clouds and strong winds portend that a storm is approaching.
Of course, this evidence hardly portends that Rick Perry will win and Mitt Romney will lose.
But the speech portends that more harmful actions are coming – and they start now.
His is an artfully composed morphology, one without pretense or the sly retouching that portends that the faux is real.
While an increase in interest rates suggests the recovery is on track, it also portends that more expensive lending could take a toll on earnings.
The Challenge: A combination of factors – from the growing number of elderly Americans, expanding government spending on healthcare, increasing market-power, and a new wave of innovations – portends that healthcare could become the defining issue for the United States.
As sure as we are black, the last year portends that there will be yet another prone black body soon enough over which we can express the "appropriate" amount of outrage.
What does it portend that the best things about city life are becoming unattainable?
Throughout Monday night, a series of one-hour extensions in the talks seemed to portend that an agreement was near.
His attention to his handset may portend that your diversion has run amok, undermining the transaction you meant to capture.
Though the show is expensive to produce, it's been highly profitable, and its success seemed to portend that a competitor would eventually emerge.
For a while, the date itself seemed to portend that Apple might finally have scored the right to sell the Beatles' music on iTunes.
