Abstract: Some 24 and 48-hr numerical forecasts for 500 mb topography over a part of Asia are prepared by graphical method with a quasi-geostrophic two-parameter model. The result is in general rather good, but for the case of blocking, the negative height-change center south to the position of ahe blocking high is not forecasted and thus the blocking high does not appear on our prognostic chart. This is due to the neglection of the 500 mb divergence which is of importance for the major development of weather systems on 500 mb level, Same of the errors is attributed to the Fjφrtoft's formula used for the graphical integration of Paisson equation.