Mr. Whitmire, a state senator, prevailed over U.S. Representative Sheila Jackson Lee to lead the nation’s fourth-largest city.

The president, Elizabeth Magill, and the chairman of the board of trustees, Scott L. Bok, are leaving after intense pressure from donors, politicians and alumni.

Numerous tornado alerts were posted in the South on Saturday, while heavy rains and winds are forecast for the Northeast on Sunday.

The Iowa Republican Party reminded supporters that only residents can vote in the first-in-the-nation caucuses, which will be held on Jan. 15.

The rivals for the Republican presidential nomination — minus Donald Trump — appeared at a “faith and family” event and talked in more personal terms.