Abstract:A “black storm ”with severe destructibility occurred in the Northwest Region of China during 4-6 May 1993 (“93.5”).In order to diagnose the heat and moisture budgets of the black storm during its development ,here used were the output data from control simulation for this case using improved MM4 with high resolution PBL parameterization and 40km fine mesh,and the equations of heat and moisture budgets.The diagnostic results for the apparent heat source(Q₁) and apparent moisture sink (Q₂) indicated that the vertical integrations of the Q₁ exhibited marked heating and cooking bands in ahead and behind parts of the black storm ,respectively.The area averaged vertical profiles of the Q₁ and Q₂ in the black storm region revealed that heating of the Q₁ for the black storm occurred mainly upper levels of the troposphere,the heating in the midtropospheric levels occurred mainly the developing early stage of the black storm,in correspondence with Q₁ ,the marked moistening cooling and drying heating of the Q₂ occurred the lower levels and middle levels,respectively.These results are not only consistent with observed rapid and intense detemperature rate and showery rain with snow due to the black storm event ,but also provides physically basis for improving and developing mesoscale numerical models used to simulate and forecast the balck storm.