Using weather facsimile and ECMWF grid report data sets,a case of long-term strong cold air gale in November in the southeast offshore seas of china was analyzed;meanwhile,the evolution of significant wave height was also discussed via NWW3 modeldata.Therefore,the developing laws of the cold air weather and the characters of itsimpacts for the sea-condition were disclosed,which is of great advantage to the sea weatherforecasting in the cold air weather situation.