Display Screen or Portion Thereof with a Transitional Graphical User Interface

FIG. 1 is a front perspective view of a handheld computing device with a display screen or portion thereof with a transitional graphical user interface showing a first image in a sequence according to the new design;

FIG. 2 is a front view thereof;

FIG. 3 is a front view of a second image thereof;

FIG. 4 is a front view of a third image thereof;

FIG. 5 is a front view of a fourth image thereof;

FIG. 6 is a front view of a fifth image thereof;

FIG. 7 is a front view of a sixth image thereof;

FIG. 8 is a front view of a seventh image thereof;

FIG. 9 is a front view of an eighth image thereof;

FIG. 10 is a front view of a ninth image thereof;

FIG. 11 is a front view of a tenth image thereof;

FIG. 12 is a front view of an eleventh image thereof;

FIG. 13 is a front view of a twelfth image thereof;

FIG. 14 is a front view of a thirteenth image thereof;

FIG. 15 is a front view of a fourteenth image thereof; and,

FIG. 16 is a front view of a fifteenth image thereof.

The design sequentially transitions between the images shown in FIGS. 2 - 16 . The process or period in which one image transitions to another image forms no part of the claimed design.

Broken lines in FIGS. 1 - 16 show portions of a computing device with the display screen or portion thereof and form no part of the claimed design.