Global three-dimensional fluid simulations in conjunction with Viking UV observations are used to investigate the response of the auroral region to solar wind pressure pulses. The fluid simulations differ from ideal MHD in that the steady state electron momentum equation which incorporates the Hall and gradient pressure terms is used instead of the idealized Ohm's law. This treatment produces important corrections to the currents that map into the noon and midnight sectors of the auroral regions and can be important in determining magnetospheric activity during periods of changing interplanetary magnetic field (IMF). Two pressure pulses observed by IMP 8 in the solar wind are shown to produce transient (a few minute) variations in the auroral oval, starting with brightenings near noon which then quickly propagate into the nightside. Of the two pulses, the second pulse which is accompanied by southward IMF produces the larger nightside activity. The model shows that the observed UV brightenings are accompanied by large increases in the auroral field-aligned currents (of the order of 1 MA) at approximately the same MLT as the UV brightenings. However, the current enhancements produced by each pulse are shown to develop along slightly different latitudes of the existing region 1 currents so that the current system can become filamented. The noon currents are also shown to be highly dependent on both By and Bz components of the IMF. ¿ 1998 American Geophysical Union