Two major dance companies one native and one foreign, will be making their Washington-area debuts this week, and what's more they'll be doing so at the same time.

The Pennsylvania Ballet will make its bow at the Carter Barron Amphitheater Tuesday night in the first of two programs which will alternate nightly through Sunday evening.

Also on Tuesday evening, the London Contemporary Dance Theater will have its U.S. premiere appearance at Wolf Trap. The London troupe will also present different programs during the two successive nights of its visit.

By an odd coincidence, both of these quite unrelated troupes originated as offshoots of larger older established dance institutions and both have evolved toward firm autonomy.

The Pennsylvania Ballet, founded in 1954 by Barbara Weisberger, took its guiding concepts and much of its initial reportory from choreographer George Balanchine, in whose School of American Ballet Weisberger received her own training.

The London Contemporary Dance Theater, founded a decade ago by Britisher Robin Howzard and American dancer Robert Cohan, was molded along the lines of the Martha Graham Dance Company of which Cohan had long been a leading member.

Under its current artistic director, Benjamin Harkarvy, the Pennsylvania Ballet maintains a repertoire of 60 ballets by a broad range of choreographers, including Harkarvy himself. It is generally regarded as the nation's finest classical ballet troupe outside New York.

The company's first program at Carter Barron to be presented Tuesday. Thursday and Saturday evenings at 8:30 includes Balanchine's "Allegro Brillante," Jose Limon's "The Moor's Pavane." Harkarvy's "Grand Pas Espagnol" and Balanchine's "Serenade": the second program consists of a new Harkarvy work with music by Dvorak called "From Gentle Circles," plus Charles Czarny's "Concerto Grosso" and Balanchine's "Raymonda Variations." The second program will be seen Wednesday, Friday and Sunday evenings.

The London Contemporary Dance Theater, which by now has achieved the enviable reputation of being the best modern dance troupe in Europe will open its Wolf Trap engagement Tuesday with "Diary 2" by Siobhan Davies, along with two works by Robert Cohan: "Cell" and "Class." The Wednesday program includes Cohan's "Masque of Separation" and "Stabat Mater," and also Robert North's "Troy Game." The curtain times both evenings will be 8:30 p.m.