Woodward & Lothrop Inc., the Washington Department store retailer, reported yesterday that first-quarter profits declined 7 percent despite an 11 percent increase in sales.

May Department Stores Co., owner of Hecht's in Washington and Baltimore, reported higher profits and record sales in the same period.

Woodies Chairman Edwin Hoffman had forecast a first-quarter earnings dip at the company's annual meeting earlier this week. Heavy snowfall in February forced stores to close and intense promotion was employed to bring back much of the volume - but with a reduction in profit margins.

Hoffman said yesterday that sales were $61.3 million in the three months ended May 5 compared with $55.3 million in the 1978 period. Profits fell to $1.14 million (47 cents a share) from $1.23 million (51 cents).

"While sales for the month of March and April were very strong, earnings for the quarter were adversely affected by serious weather conditions during the month of February," Hoffman stated.

First-quarter operations nomally contribute the smallest percentage of total year profits for Woodies but Hoffman said that programs to monitor all aspects of the business will result in a "high level of profitability" for the balance of the year.

May department stores, based in St. Louis, reported yesterday a 30 percent increase in first-quarter profits. Sales gains at existing department stores were particularly strong, officers said. Earnings were $8.8 million (39 cents a share) in the three months end May 5 compared with $6.7 million (30 cents) a year ago. Sales rose 15 percent to a record $562 million.