I-94
Don't think Oklahoma City...think I-94. A passport may come in handy. So will lots and lots of water.
I just checked out the 6/18 0Z GFS run and the SPC convective outlooks, and the Plains south of I-80 are in for a heat wave with little precipitation. The Dakotas, Canadian Prairies and the Midwest plan to host the northeast quadrant of a ridge over the central and southern Plains for the next two weeks.
In very rough terms, a weak cold front will go through the Great Lakes on June 21, but the Plains ridge will assert itself on the 23rd in brutal terms (97 F in Minneapolis and Chicago, 100 F in Des Moines). On the 24th, an area of convection from Minneapolis to Detroit is expected.
Beyond that, models can only tell the most general trends. It's tempting to say that the I-94 corridor will be hovering around 95 F from June 23 to July 2, but more than a week out, all that can be said with any assurance is "above normal temperatures likely".