A fully analytic ionospheric model emphasizing the low-latitude F region for various seasonal and solar cycle conditions is presented. Features such as the postsunset rise in the F layer peak height and the ''equatorial anomaly'' maxima in plasma density near ¿15¿ geomagnetic latitude are designed to closely approximate those in the semiempirical low-latitude ionospheric model (Anderson et al., 1987a). Significant improvements are thus obtained over previous comparable analytic models. Numerical computations are also presented which demonstrate the importance of these large-scale plasma structures to the neutral dynamics of the low-latitude thermosphere. Equally significant effects are anticipated for electrodynamic simulations of E region/F region coupling involving flux tube integral electrical conductivities. ¿ American Geophysical Union 1989