Delta Air Lines said it expects to return to normal operations later on Wednesday after a power outage hit its computer systems on Monday, causing the cancellation of more than 1,600 flights over two days.

The company said it would start operations with a little more than 150 cancellations on Wednesday after roughly 800 flights were canceled on Tuesday. 

However, the airline said scattered thunderstorms forecast for the eastern United States could slow the recovery.

Systems that allow customer service agents to process check-ins and dispatch aircraft are functioning normally, Delta said, with most delays and cancellations a result of flight crews displaced or running up against maximum allowed duty periods.

Delta, the No.2 U.S. airline by passenger traffic, has yet to detail the financial impact of the disruption.

Rival Southwest Airlines Co forecast on Wednesday a further drop in a key profitability metric for the current quarter due to delays and cancellations of more than 2,000 flights after an outage hit its computer systems in July.

The budget airline also said it expected its unit costs to increase more than it had forecast earlier due to the outage that was caused by the failure of computer equipment supporting the carrier's network.

Delta's problems arose after a switchgear, which helps control and switch power flows like a circuit breaker in a home, malfunctioned for reasons that were not immediately clear.

Georgia Power, a unit of Southern Co, provides electricity to most counties in Georgia, where Delta is based. 

Reuters (Reporting by Abinaya Vijayaraghavan and Arunima Banerjee in Bengaluru; Editing by Gopakumar Warrier and Maju Samuel)