Maverick Storm Drops a Record June Rainfall : Weather: Remnants of Hurricane Boris lead weathermen on a meteorological chase and topple a mark that had stood for 140 years.

The remnants of Hurricane Boris continued to provide unusual June weather in San Diego on Sunday, breaking a 140-year-old record for the most rainfall in the month.

As of 4 p.m. Sunday, 0.87 inches of rain had been recorded by the National Weather Service at Lindbergh Field, surpassing the 0.68 inches measured in 1850, the first year for which data exist in San Diego.

“This was a tough storm to forecast,” San Diego meteorologist Wilbur Shigehara said Sunday. “Boris gave us nightmares because its punch was such a surprise.” Mt. Laguna reported 1.41 inches, the county’s highest amount.

As the area’s weather reverts to a more normal June pattern today--with the usual morning clouds and hazy afternoon sunshine expected to return fully by Tuesday--Shigehara and his colleagues are still scratching their heads over the residual strength of Boris, which moved north from tropical waters off Acapulco, where it had developed as a hurricane early last week.

“Usually a dying tropical storm dies quite rapidly when it comes up here so early, because our offshore waters are still quite cold,” Shigehara explained. A hurricane develops its tremendous force over warm water and will dissipate quite rapidly when it hits colder currents, he said.

In addition, high-altitude winds steered the storm’s remnants on a more northerly course into the San Diego area instead of the usual track over Baja California and into the Sonoran desert of northern Mexico and southern Arizona, he said.

Therefore, when the moist, warm air from Boris clashed with dry, colder air over San Diego, the stage was set for spectacular lightning and thunder Saturday. As the unstable air mass warmed the entire county, the rain persisted into Sunday, with occasionally heavy amounts in the early morning.

“We saw this big mass of clouds on the satellite photos but simply didn’t know (how much strength) was in it,” Shigehara said. “Our radar is only good up to 100 miles, and when this storm is coming in at 25 miles an hour, it’s hard to keep the forecast on target. . . . In this case, we had to keep renegotiating our forecasts.”

Shigehara said the five biggest tropical storms to affect San Diego since the 1930s have all come in late August or early September, when warm offshore waters and late-summer weather patterns are more conducive to bringing the storms near Southern California.

Residents along the coast can expect a slight chance of drizzle or light rain early today as remaining storm clouds move east. Skies will turn partly cloudy by afternoon, with low clouds tonight and Tuesday morning, followed by sunshine, Shigehara said.

Highs will range from 70 to 76 degrees both days. The high Sunday was 72 at Lindbergh Field, and the low 67.

THE RAIN

24-hour total: 0.49 in. Storm total: 0.87 in. Monthly total: 0.87 in. Total for season: 7.84 in. Last season to date: 5.65 in. Normal season to date: 9.32 in.

Figures, based on 4 p.m. readings at Lindbergh Field, are compiled by the National Weather Service, which provides no later data.