Microdischarges have been the subject of numerous studies in the past decade. Numerical modeling has become a powerful tool to complement to the scarce experimental data on microdischarges, as their small size poses a great number of difficulties in implementing traditional experimental techniques. It has been shown that in atmospheric air discharges, gas heating becomes an important factor, greatly influencing plasma parameters and leading to transition from normal glow discharge to obstructed mode with abruptly growing current-voltage characteristic. Presented images of electron density distributions and volt-ampere characteristics confirm this interesting phenomenon.