The American Red Cross is appealing for persons to donate blood because of a seasonal shortage of blood supplies expected to last through January. All types of blood are needed, but the "O" groups are the most critically in need.

The Washington region of the Red Cross Blood Services supplies most of the blood and blood products used by more than 60 hospitals in the region. Scheduled surgery is postponed when supplies are short.

Persons can contact their local Red Cross chapter for a donor location, or call 857-3400 for more information. Most local hospitals have facilities for blood donations, but persons should telephone first to make an appointment or find out hours of operation.

Following is a listing of bloodmobile schedules in suburban Maryland. Persons are urged to telephone to confirm the hours and to ask if they are eligible to be donors. Jan. 8

Elevators Union, Chillum-Adelphi Fire House, 7833 Riggs Rd., Adelphi, 2 to 8 p.m., 554-2963.

Silver Spring Seventh Day Adventist Church, 8900 Colesville Rd., 3 to 8 p.m. (closed 5 to 6 p.m.), 589-5768.

Watkins-Johnson, 700 Quince Orchard Rd., Gaithersburg, 9:30 a.m. to 3:30 p.m., 948-7550, ext. 230. Jan. 9

Lds Church, 3790 East-West Hwy., Hyattsville, 9 a.m. to 3 p.m., 277-9970.

Volkswagen, 9300 George Palmer Pkwy., Lanham, 9 a.m. to 3 p.m., 459-7000. Jan. 10

Silver Spring Chapter house, 2020 East West Hwy., 9 a.m. to noon, for appointment call Mrs. Gassmann at 585-2515. Jan. 12

Potomac High School, 5211 Boydell Ave., Oxon Hill, 8:30 a.m. to 2:30 p.m., 894-2300.

McArdle Printing, 1140 East West Hwy., Silver Spring, 1 to 6 p.m., 588-5025. Jan. 13

Bechtel Power Corp., 15740 Shady Grove Rd., Gaithersburg, 9:30 a.m. to 3:30 p.m., 948-2700, ext. 2966.

Northwestern High School, 7000 Adelphi Rd., Hyattsville, 8:30 a.m. to 2:30 p.m., 779-5400.

Springbrook High School, 201 Valley Brook Dr., Silver Spring, 8:30 a.m. to 2:30 p.m., 662-0710. Jan. 14

American Legion, Northern Ave., Hagerstown, noon to 6 p.m., 733-7676.

Bechtel Power Corp. 15740 Shady Grove Rd., Gaithersburg, 9:30 a.m. to 3:30 p.m., 948-2700 ext. 2966.

C&p Telephone Co., Gaither Rd., Gaithersburg, 9:30 a.m. to 3:30 p.m., 770-4994. Jan. 15

Montgomery County Public Schools Maintenance Division, 16651 Crabb's Branch Way, Rockville, 9:30 a.m. to 3:30 p.m., 977-1243. Jan. 16

Rockville City Hall, 111 Maryland Ave., 9:30 a.m. to 3:30 p.m., 279-1281. Jan. 17

ARC Chapter House, 6206 Belcrest Rd., Hyattsville, 9 a.m. to 1 p.m., 559-8500. Jan. 19

Damascus Lions, Methodist Ed. Center, Main Street & Woodfield Road, Damascus, 2 to 8 p.m., 730-1510.

Sheraton Hotel, Shady Grove Road, Gaithersburg, 9 a.m. to 3 p.m., 840-0200.

Jan. 20

GEICO (Government Employees Insurance Company), 1701 Research Blvd., Rockville, 9 a.m. to 3 p.m. Jan. 22

GEICO, 5260 Western Ave., Chevy Chase, 9 a.m. to 3 p.m. Jan. 23

NOAA, St. Marks United Presbyterian Church, 10701 Old Georgetown Rd., Rockville, 9 a.m. to 3 p.m. Jan. 23

Seneca Valley High School, 12700 Middlebrook Rd., Germantown, 9 a.m. to 3 p.m. Jan. 26

Beth Tikva Synagogue, 2200 Baltimore Rd., Rockville, 2 to 8 p.m. Jan. 27

IBM-Holiday Inn, 18100 Frederick Pike, Gaithersburg, 9:30 a.m. to 3:30 p.m.