Display screen or portion thereof with transitional graphical user interface

FIG. 1 is a front view of a first image in a sequence according to a first embodiment of our design for a display screen or portion thereof with transitional graphical user interface;

FIG. 2 is a front view of a second image in the sequence thereof;

FIG. 3 is a front view of a third image in the sequence thereof;

FIG. 4 is a front view of a first image in a sequence according to a second embodiment of our design;

FIG. 5 is a front view of a second image in the sequence thereof;

FIG. 6 is a front view of a third image in the sequence thereof;

FIG. 7 is a front view of a fourth image in the sequence thereof;

FIG. 8 is a front view of a first image in a sequence according to a third embodiment of our design;

FIG. 9 is a front view of a second image in the sequence thereof;

FIG. 10 is a front view of a third image in the sequence thereof;

FIG. 11 is a front view of a first image in a sequence according to a fourth embodiment of our design;

FIG. 12 is a front view of a second image in the sequence thereof;

FIG. 13 is a front view of a third image in the sequence thereof;

FIG. 14 is a front view of a fourth image in the sequence thereof;

FIG. 15 is a front view of a first image in a sequence according to a fifth embodiment of our design;

FIG. 16 is a front view of a second image in the sequence thereof;

FIG. 17 is a front view of a third image in the sequence thereof;

FIG. 18 is a front view of a first image in a sequence according to a sixth embodiment of our design;

FIG. 19 is a front view of a second image in the sequence thereof;

FIG. 20 is a front view of a third image in the sequence thereof;

FIG. 21 is a front view of a fourth image in the sequence thereof;

FIG. 22 is a front view of a first image in a sequence according to a seventh embodiment of our design;

FIG. 23 is a front view of a second image in the sequence thereof;

FIG. 24 is a front view of a third image in the sequence thereof;

FIG. 25 is a front view of a first image in a sequence according to an eighth embodiment of our design;

FIG. 26 is a front view of a second image in the sequence thereof;

FIG. 27 is a front view of a third image in the sequence thereof; and,

FIG. 28 is a front view of a fourth image in the sequence thereof.

The appearance of the transitional image transitions between the images shown in FIGS. 1 through 3 , between the images shown in FIGS. 4 through 7 , between the images shown in FIGS. 8 through 10 , between the images shown in FIGS. 11 through 14 , between the images shown in FIGS. 15 through 17 , between the images shown in FIGS. 18 through 21 , between the images shown in FIGS. 22 through 24 , and between the images shown in FIGS. 25 through 28 , respectively. The process or period in which one image transitions to another forms no part of the claimed design.

The outermost broken line rounded rectangle showing an electronic device illustrates environmental subject matter. The broken line showing a display screen, and all other broken lines showing portions of the graphical user interface illustrate portions of the article. None of the aforementioned broken line subject matter forms part of the claimed design.