WHUR-FM (96.3), the pioneering urban station that has three of the top-rated music shows in town and a popular daily news hour, is adding a news-magazine program and a countdown show on Sundays. Starting June 1, WHUR is also dropping its descriptive "progressive 96" tag for "super 96."

"We are not really known in the market as the progressive station, but simply as WHUR," said general manager Robert Taylor. We thought the 'super 96' concept would fit more with the degree of sophistication of the station and the listeners." WHUR, which is owned by Howard University, had boasted its "progressive" slogan since 1978.

On June 2 at 11 a.m., WHUR will institute "The Sunday News Hour" with news editor Bill Christian. The show is modeled on both WHUR's "Daily Drum," the only one-hour news show on a commercial music station, and CBS' "Sunday Morning." "Drum" ranks sixth in its time slot, according to the most recent Arbitron ratings, beating all-news WTOP-AM (1500). "Super 96 Top 20 Countdown," based on the station's own research and hosted by Wendell Williams, starts at noon the same day.

Taylor said the changes were not because of WHUR's slip in the last Arbitron survey. Even though it fell one notch in rankings to No. 5, it did hold its audience at a 6.5 share. Three of its programs have the largest audiences in their time slots: the weekday and weekend "Quiet Storm," the overnight "Inflight" and the Sunday morning gospel show.

During the past 15 months, the station has had personnel changes, programming changes and philosophical debates over its direction. In August WHUR renamed its format urban adult. Last year it dismissed several key employes, including music director Oscar Fields, who filed a grievance with the university, lost one round and decided not to go ahead when offered a new hearing. He is now considering a civil suit, according to his attorney.

A reporter, Margaret Summers, filed a grievance through the American Federation of Television and Radio Artists and won a financial settlement and removal of her termination letter from her personnel file.

Terry Mphahlele, a part-time reporter, was placed on a 30-day "reassessment period" following a sharp exchange with the participants at a press conference on South African business and politics that she was covering in late March. Taylor said this week that a decision on her status would be decided within a week. Drug Campaign

In a rare programming move, WPFW-FM (89.3) is giving up 12 straight hours starting at 10 a.m. Wednesday for a discussion of drug problems in the metropolitan area. Gaston Neal, a special projects coordinator with the Alcohol and Drug Abuse Services Administration, has helped put together 30 experts from prevention and treatment programs and federal and local agencies, as well as former and current users. Mayor Barry is tentatively scheduled for a 3:30 p.m. call-in. Duck's Breath

Charlie's Georgetown has scheduled a one-night-only appearance Monday by Duck's Breath Mystery Theater, the zany five-man troupe. Its 90-second weekday feature, "Ask Dr. Science," distributed by American Public Radio, is carried by WETA-FM (90.9). Charlie's showtimes: 8:30 and 10:30 p.m. Antenna Blues

A freak storm knocked out WHFS-FM (99.1) and WNAV-AM (1430) for six days. "This is the $12,000 experience," said owner Jake Einstein, overseeing the repair of 371 feet of transmission line. The station was scheduled to go back on the air last night. May Special

For the next three Sundays WMZQ-FM/AM (98.7/1390) will be discussing drunk driving and related subjects on "Spectrum," which airs on the AM at 6 a.m. and the FM at 6:30 a.m. The station is scheduling a remote Monday morning from a hot air balloon that warns, "Don't Drink and Drive." Additions

Starting next week, WNTR-AM (1050) will present "On Your Mind" with psychiatrist David Charney and therapist Jerilyn Ross each Tuesday and Thursday at 6:30 p.m. . . . Les Carpenter of WWRC-AM (980) has started an hour-long feature at noon Mondays spotlighting a band or artist, such as Irving Berlin, this Monday's choice. On Fridays Carpenter dips into the old "Your Hit Parade" archives for a review of a week between 1940 to 1950. Datebook

WHUR will broadcast the Howard commencement featuring writer Maya Angelou at 10 a.m. tomorrow. WDCU-FM (90.1) will feature the University of the District of Columbia ceremonies at the same time . . . WPKX-FM/AM (105.9/730) is cosponsoring the sixth annual Nation's Capital Chili Cookoff tomorrow from 11 a.m. to 6 p.m. on the Georgetown waterfront. More than 33 cooks, six restaurants and 12 vendors will dish up beans and trimmings for the National Kidney Foundation. Admission is $2 and the first 3,000 people get special discount tickets . . .