A diagnostic package developed to analyze runs made by the National Center for Atmospheric Research thermospheric general circulation model (TGCM) is used to calculate neutral parcel trajectories in the high-latitude E and F regions. The calculations are made considering steady, time-invariant magnetospheric convection and auroral forcings for moderate levels of geomagnetic activity (Kp~3 or 4 and cross-polar cap potential of 60 kV). Individual parcels of neutral gas are tracked by interpolation through the TGCM grid time and space. Trajectories are calculated to illustrate the predicted loci of thermospheric neutral gas parcels that encounter high-latitude ion drag forces. The forcing histories for such parcels are determined by decomposing terms in the hydrodynamic equations used in the model calculations. Trajectories, analyzed for ''steady state,'' diurnally reproducible runs of the TGCM, have shown that (1) the magnetospheric convection throat region plays an important regulatory role for the overall flow pattern at high latitudes, (2) the trajectories of typical F region neutral gas parcels pass through the throat region at least once and sometimes twice in a 24-hour period as a result of the convergent geometry of the ion convection pattern, (3) parcels transiting the dayside cusp region are heated rapidly in the region of soft particle precipitation and this energy is then advected over the polar cap and deposited several hours ''downstream'' along the parcel trajectory heating the polar cap, (4) the ''postmidnight'' surge in the meridional neutral wind is a result of parcel acceleration in the convection throat region and subsequent deflection towards the corotation direction, and (5) E region parcels move less rapidly than their F region counterparts and can dwell for appreciable periods of time in the auroral oval. Few geometrically selected parcels escape to lower latitudes.