US President Barack Obama on Saturday called governors of states hard-hit by tornadoes to vow government aid after more than 30 people were killed in storms a day earlier. Harsh weather was continuing across the southern and central United States, with a slight risk of severe thunderstorms in the south and strong winds in the Great Lakes region, the National Weather Service warned. As many as 85 tornadoes on Friday had left an estimated 36 people dead, as towns in central states from Alabama to Indiana began to cleanup the destruction, the (CNN) reported. Obama consulted with federal emergency officials and called the governors of Indiana, Kentucky and Ohio to express his concerns for residents in their states and offer condolences to families of those killed, the White House said. \"The president acknowledged that the extent of damage may not be known for days, and reiterated to each governor that FEMA (the Federal Emergency Management Agency) stood ready to provide assistance, if necessary, to the extensive response efforts already underway in each state, led by the governors\' teams,\" the White House said in a statement. The storms came just two days after an earlier rash of tornadoes left at least 12 dead. Forecasters have warned that conditions this year could produce an above-normal tornado season, following on the heels of last year when the fourth-most storms on record were recorded and more than 550 people were killed.