The first self-consistent study of the impact of storm-time penetration electric fields on the low- to mid-latitude ionosphere is presented. The inner magnetosphere is described by the Rice Convection Model (RCM) and the ionosphere is described by the Naval Research Laboratory (NRL) code SAMI3. The codes are coupled electrodynamically through the electrostatic potential equation, and the storm is modeled via changes in the polar cap potential. Neutral wind driven electric fields are estimated from the Fejer/Scherliess quiet time model. It is found that temporal changes in the polar cap potential produce electric fields that modify the F region equatorial E ¿ B drift velocities: the velocities increase in the daytime and decrease in the nighttime by up to a factor of two. This causes the total electron content (TEC) in the daytime, mid-latitude ionosphere to increase by up to 35%. In addition, the 'fountain effect' is enhanced in the post-sunset period.