Charlene Drew Jarvis figures Washington's race for mayor this way:

Incumbent Marion Barry's support will not grow and Patricia Roberts Harris will fade before the Sept. 14 primary, leaving room for Jarvis to dash into the lead with strong support from the ward that elected her to the City Council--Ward 4, with the highest number of Democratic voters in the city--and win at the wire in a close race.

"Timing is everything," said Jarvis in a recent interview in her council office. "If you asked me today if the election took place today could I beat Marion Barry, I'd say no. If you ask me in September, or ask me now if I'm on the way to winning, the answer is yes. I'm going to win."

Most people believe Jarvis' scenario is an unlikely one. She has raised the least money of the mayoral candidates and attracted the least support in early polls. While other council members running for mayor have bought television or radio ads to try to increase their name recognition, Jarvis hasn't been able to afford to do so.

In fact, the question asked most often about the council member is not if she can win, but, as an elderly woman asked a reporter after a forum at Wilson High School: "Son, why is Miss Jarvis bothering at all with this?"

"I have enough positive indications to stay in the race," Jarvis said in her office, a large reproduction of a U.S. postage stamp bearing a picture of her father--Charles Drew, a pioneer in blood plasma research--hanging nearby.

"I'm not limping along, I'm not in debt like some other candidates, I'm growing. All these other people have been in the race since last year and raised money. But we're all about the same in the polls and I've only been in the race three months.

"I'm growing and they're dying down," she said.

But a steady rain of doubts and questions about Jarvis' campaign has fallen since she announced to a crowd of 34 people on a drizzly Saturday morning that she would run for mayor--an audacious move for someone who had only been involved in local politics for less than four years.

Even before Jarvis entered the mayor's race there had been speculation that if she did run it would only be because she was angry at her Ward 4 supporters for leaning to Harris, a candidate who has not held local office in the city before.

She was also said to be unhappy with City Council chairman Arrington Dixon and his former wife, Sharon. The Dixons, who were recently divorced, urged Jarvis to leave her career as a scientist and run for the Ward 4 seat to replace Arrington Dixon after he was elected chairman.

It was a transfer of power from one native Washingtonian to another: Jarvis is a fourth-generation Washingtonian, and often makes a point of that when speaking to voters.

According to District Building sources, Jarvis had planned to follow Dixon again, running for council chairman on a slate led by a Dixon mayoral candidacy. She confirms that she considered this. But Dixon decided to run to keep his current post, and has failed to endorse anyone for mayor. Sharon Dixon, meanwhile, is now Harris' campaign director.

"There were discussions about whether the chairman should run for mayor," said Jarvis. " . . . even when he decided not to run, many, many people encouraged me to run for his seat . . . now I need his support for my campaign for mayor. He doesn't understand the pressure that was on me to run against him . . . I could have put him out of his job. You know I've been supportive of him the entire time I've been on the council."

Dixon, who is in a three-way race with Ward 1 council member David Clarke and former council chairman Sterling Tucker, said he spoke to Jarvis when he decided not to run and told her she should not enter the mayor's race.

"I told her I didn't know why she should be in the race," Dixon said. "I don't see her having a chance to win it."

When Jarvis announced her candidacy for mayor she said she was a serious candidate and in the race to win--not running to get ready for four years from now. In front of the boarded-up Upshur Street Clinic, Jarvis said her campaign theme would be the need to improve the city's health care system; her campaign slogan, she said, would be that the "health of the city is in the health of its people."

Jarvis' campaign on the health issue and her general attacks on Barry for failing to monitor the performance of city programs have netted her good reaction in forums, but that applause has yet to translate into major support for Jarvis' campaign.

"You tell me who is going to vote for her because of problems with health care," said Barry. "It's no major issue for her to run on. I'm not saying it public health care in Washington couldn't be better, but it's a single-issue campaign."

Jarvis said she has widespread support across the city, but said she is working hardest to maintain her base in Ward 4, a generally middle-class, well educated, predominantly black area of the city. That constituency is thought to be attracted to Harris.

Even with naysayers in political circles shaking their heads at her candidacy, Jarvis has proven to be a warm, charismatic campaigner in forums, wearing colorful, pastel suits and easily joking with her audience--in sharp contrast to other candidates, who often seem defensive or nervous.

For instance, at a recent forum where all the candidates were seated behind a table, Jarvis was the first to stand up and walk around to the front to speak directly to the voters. "I'm not hiding," Jarvis said with a wide smile, "I'm going to come out here and talk to you." Her two teen-aged sons, who often accompany her to evening forums, applauded loudly at the comment.

When the question of controlling street drug traffic came up, Jarvis didn't answer with a drawn-out proposal and big statistics. She told the story of two teen-agers talking about going to Kennedy Street, a main strip in her ward, to buy "a nickle bag" of marijuana.

According to Jarvis, who said she heard the story from one of her sons, one teen-ager turned to the other and said, "No, man, you can't go up there to cop. Charlene took care of that." The story brought smiles, laughter and nods of approval from the crowd.

Jarvis would not say in an interview who her major constituencies are, explaining that she appeals to most groups. As for her lack of money, Jarvis said it has not hurt her campaign, although she said she needs about $200,000 more to finish the race.

Jarvis has raised about $28,000 and has about $14,000 left. Although she has raised the least money, Jarvis now has about as much money in hand as council member John Ray and more than council member Betty Ann Kane. Harris and Barry are by far the leaders in the amount of ready cash they have, as the campaign approaches the last three months.

"The other campaigns are promoting the idea that I'm going to drop out," said Jarvis. "I think both of them Harris and Barry are doing it. But I'm not going anywhere. I'm going to win."