Proximity wall stabilized, fast (>4 × 1011 A/s), high current (>40 kA) discharges are capable to create long, dense, hot, stable, non-equilibrium plasma column, suitable e.g., for radiation amplification or even for lasing in extreme ultraviolet and soft X-ray region. Exploding wire in water resembles a metal-vapor-filled capillary with liquid, ever fresh wall (without any metallic deposit). Modeling of wire explosion (inclusive melting and boiling phase transitions, thermal diffusion, and variable conductivity) by the originally skinned driving current is described. Modeling results are compared with measurement of the discharge current and with side-on and end-on monitoring of H-alpha line emission. Analysis of H-alpha line profile is used for diagnostic of water-vapor layer around the wire. The differences between model and reality are attributed to the fact that the pressure dependence of material constants was neglected in the first approximation.