An Early Fall : Television: NBC will introduce five new series this week. ‘Hull High’ and ‘Lifestories’ offer a bizarre pairing tonight.

A fall season in summer?

That is what NBC is implementing this week as it introduces five of its new series in an attempt to distinguish them from the competitive crush of season premieres that traditionally arrives in September. As part of its strategy, NBC will air these episodes, all of which are pilots, a second time before next month’s official start of the 1990-91 season.

Three of the series--”Hull High,” “Lifestories” and ‘Parenthood”--open tonight (on Channels 4, 36 and 39). “Working It Out” airs Wednesday and “Ferris Bueller” Thursday.

Because the “Parenthood” provided for screening does not include two recent cast changes reflected in the episode viewers will see, it won’t be reviewed here.

Premiering tonight at 8 (its regular time slot is 7 p.m. Sundays) is high-stepping “Hull High,” a style-thick, plot-thin hour whose classroom escapades become a prelude to the new season’s rash of high-schooler comedies.

Marking the directing debut of “Dirty Dancing” choreographer Kenny Ortega, “Hull High” introduces a California high school where the cheap double-entendres are mildly risque and the plot--such as it is--moves to the rhythm of musical fantasies.

In the opening story, wiggly new English teacher Donna Breedlove (Nancy Valen) wears thin tops and clingy miniskirts, yet just can’t fathom why her class finds her more arresting than what she’s teaching. So, she asks veteran history teacher John Deerborn (Will Lyman) to sit in her class and “examine my moves” to make her a better teacher. Oh, Donna.

The “moves” he sees are epitomized by a daydreamy sequence showing the centerfold teacher wearing tight red pants during a song, “Soft and round as a peach . . .,” which rather appropriately describes her rear end.

In photography class, by the by, free-spirited D.J. (Kristin Dattilo) wants the twirpy Louis (Marty Belavsky) to shoot her in the raw in the boys’ shower. And in the only hint of a real plot, the all-American Mark (Mark Ballou) becomes convinced by gossips that his urbane new girlfriend Camilla (Cheryl Pollak) is an undercover narc. Ooooh, the mystery mounts. Meanwhile, a rap group moves around the school doing what rap groups do.

This is stickless, wipe-away TV that, like some of its young protagonists, hopes to get by on looks and personality, not brains. And even though this is far more flirty dancing than dirty, an early time period of 8 p.m. or 7 p.m. is hardly ideal for any kind of sex gags.

Yet credit “Hull High” with fast-cutting energy, glossy production and a mocking, winking sense of humor evidenced by tight shots of the ticking school clock that are meant to symbolize its pervasiveness in the thoughts of students and faculty. When they are not thinking of peaches.

Infinitely more rewarding and valuable, meanwhile, is “Lifestories,” the medical anthology series that makes a striking debut at 10 tonight (regular time slot: 8 p.m. Sundays) with a deeply tender and affirming story about a man whose life is dramatically altered--but curiously enriched--through serious illness. He has colon cancer.

Don’t be put off. This is neither depressing nor a denial of reality. It is, well, just right. I watched the hour three times, and was moved each time.

“Lifestories” is a sort of medical “Our Town,” with an unseen narrator (Robert Prosky) each week relating the story of a different patient. He does this mostly by exposing their own private thoughts and feelings and those of persons around them.

Tonight, 47-year-old developer Don Chapin (Richard Masur), an ordinary guy living in an ordinary town, learns that he has colon cancer. He has the ideal life--good family, successful business. He asks what everyone asks at times like this when they are confronted by their own mortality: “Why me?”

Chapin has the proper surgery, reads “War and Peace,” gets chemo that makes him feel lousy, thinks about things and takes a fresh look at his life. He decides to change it, ultimately cleaning the slate by revealing a secret to his wife (Lisa Banes).

Directed by Don Patterson, the premiere of “Lifestories” ripples with intelligence, honesty and feeling. It’s emotional without being manipulative.

Executive producer/creator Jeffrey Lewis has written a script whose lovingly poignant characters avoid the ruts and easy answers that epitomize most TV dramas with medical themes. Without disturbing the flow, Lewis manages to slip in some crucial data about colon cancer that may prompt you to run right out and get tested. Unlike typical affliction dramas, however, there is no pretentious lecture here, and although ever-looming, the cancer never eclipses the human story. Chapin simply must face his greatest fears and live through them.

From the story’s beginning to its twist ending, Masur is always believable, never doing too much, using wit and subtlety to give us an Everyman who hides inner worry behind a benign smile. Banes is excellent as his wife.

What a bizarre pairing “Hull High” and “Lifestories” will make from 7-9 p.m. Sundays.

TV series themselves are as uncertain as illness, with the immediately apparent not always an indication of what’s yet to be revealed. Based on its premiere, however, “Lifestories” is arguably the most important new series of the fall season, and undoubtedly one of the best.