Whenever the Governor shall ascertain that the cash balance and the current estimated receipts of the General Fund or of the Motor License Fund shall be insufficient at any time during any fiscal period to meet promptly the expenses of the Commonwealth payable from either fund, the State Treasurer is hereby authorized and directed, from time to time during such fiscal period, to transfer to such fund from the Motor License Fund or the General Fund, as the case may be, such sums as the Governor shall direct. Any sums so transferred shall be available for the purposes for which the fund to which they are transferred is appropriated by law. Transfers shall be made hereunder upon warrant by the Auditor General upon requisitions of the Governor.