NEW : Mandatory evacuations set to begin 8 a.m. Sunday in New Orleans . Hurricane watch issued from southeastern Texas to Alabama-Florida border . The storm is expected to move slowly over the next few days and could bring heavy rain or flooding as it moves up through Louisiana and Mississippi on Sunday. Gustav 's sustained winds reach 150 mph as it roars past Cuba .
NEW : Mandatory evacuations set to begin 8 a.m. Sunday in New Orleans . Hurricane watch issued from southeastern Texas to Alabama-Florida border . Thousands evacuating Gulf Coast on buses , trains , planes . Gustav 's sustained winds reach 150 mph as it roars past Cuba .