UPDATE 1-Delta Air Lines reports higher revenue, but weighed down by fuel, storms

storms@ (Adds details on earnings)

April 12 (Reuters) - U.S. carrier Delta Air Lines Inc reported a 9.5 percent rise in quarterly revenue on Thursday, boosted by higher average fares and passenger traffic.

However, the Atlanta-based carrier's net income fell to $547 million in the first quarter ended March 31 from $561 million a year earlier. Higher costs, including a spike in fuel prices and a $44 million negative impact from severe winter storms, weighed on its bottom line.

Delta, the No. 2 U.S. airline by passenger traffic, reported earnings per share had remained flat at 77 cents.

Total operating revenue for the first quarter rose to $9.97 billion from $9.10 billion and the carrier forecast total unit revenue - a key metric which compares sales with flight capacity - would increase 3 percent to 5 percent in the second quarter.

Delta said its operating expenses for the quarter swelled by $817 million from the last quarter, driven primarily by increases in fuel and labor costs, and a higher depreciation expense. (Reporting by Alana Wise in New York and Arunima Banerjee in Bengaluru; Editing by Sriraj Kalluvila and Chizu Nomiyama)