CAMARILLO, Calif. (AP) _ Gasoline prices jumped about half a cent, the first price increase since September, thanks to a rise in crude oil prices and a slight tightening of supply, an industry analyst said Sunday.

The weighted average, including all grades and taxes, was $1.0028 per gallon Friday, up 0.48 cent from two weeks earlier, according to the Lundberg Survey of 10,000 gas stations nationwide.

``If this is a price recovery after about a year and a half of price cutting, then it is so far a frail one,'' analyst Trilby Lundberg said.

West Coast prices increased after the Feb. 23 explosion at a Tosco Corp. oil refinery in Martinez, Calif., which killed four people and sent gas buyers chasing for alternative supplies, she said.

She warned that the tightening of gas supplies might create glut conditions prior to the spring driving season.

``We're still weeks away from what the industry calls spring demand, when we consume a lot more fuel, but this is the period of time that both society and oil industry shift from heating oil to driving supplies for greater demand in spring,'' Ms. Lundberg said.

Self-service prices were 94.16 cents for regular, $1.0517 for mid-grade and $1.1362 for premium.

Full-service prices were $1.4002 for regular, $1.4915 for mid-grade and $1.5662 for premium.