Using the current apportionment formula (known as the Method of Equal Proportions), we can estimate the following changes:

Texas should gain three seats
Florida should gain two
North Carolina, Colorado, Arizona, Montana and Oregon should gain one each
Alabama, California, Minnesota, Illinois, Michigan, Ohio, West Virginia, Pennsylvania, New York, and Rhode Island should each lose a seat.

Of course, it is difficult to know exactly how this would play out in redistricting. Obviously, the West Virginia and Rhode Island seats would have to be taken out of the Republican and Democratic columns, respectively (barring a major surprise next year). It is difficult to eliminate an additional Democratic seat from Ohio (though not impossible), while drawing an additional Democratic seat in Oregon is unlikely (though not impossible).

In the Electoral College, President Trump would gain electoral votes, but these changes would not take effect until the 2024 election (Trump could theoretically run if he loses in 2020).