After three days of radio silence following his withdrawal from the governor's race, San Francisco Mayor Gavin Newsom unexpectedly jetted off Tuesday morning to Hawaii to join his wife and baby daughter, who already were vacationing there.

The trip, which the mayor apparently booked on his own, caught his staffers off guard. Many did not know he was gone until the city attorney's office sent out a notice informing them that the mayor had left the state and naming Supervisor Carmen Chu acting mayor.

Mayoral spokesman Nathan Ballard apparently was among those who did not get a heads-up about the trip. Just an hour before Newsom's plane took off, Ballard was peppered with questions about Newsom's absence from former Mayor Willie Brown's election morning breakfast.

Ballard said the mayor was "feeling under the weather," because that's what he'd been told over the weekend.

The weather is just fine where Newsom is going. And Hawaii isn't the worst place to assess one's future.

After all, his aloha comes as heads are still spinning over his abrupt withdrawal from the governor's race - although his pullout was less than a shock, with Newsom's poll numbers stagnating and his money drying up.

It was such a stressful time for the mayor that he huddled at City Hall in the final days of his campaign with someone alternatively described as a "life coach" and "corporate facilitator."

No word if the mystery man accompanied Newsom to the islands. And no word on when Gavin plans to come back to town.

Taxing troubles: News that Oakland Mayor Ron Dellums and his wife owe the Internal Revenue Service at least $239,000 in back taxes helps solve one mystery - why Dellums never pressed for the ambassadorship to South Africa that his staff was lobbying for him to get.

No doubt, had Dellums been fully vetted for an ambassadorship or any other job with the Obama administration, his tax troubles would have bubbled right up.

The lien that the IRS slapped on the Dellumses' personal property was filed Oct. 14, but the tax collectors typically send out warning notices for months in advance before taking such a step.

Dellums still owns a house in Washington, D.C., which friends say he has been renting out. At the same time, he's been living in an expensive rental property on Oakland's Skyline Boulevard.

"It's just a situation where he was living above his means," says a friend.

By the way, amid all the talk about Dellums' tax problems, Chronicle reporter Jaxon Van Derbeken points out this bit of irony: The IRS offices are housed right in downtown Oakland - in the Ronald V. Dellums Federal Building.

Coach vs. coach: The Alameda County district attorney's office says it will decide in the next couple of days whether to bring battery charges against former Raiders tight end Jeremy Brigham, following allegations that he assaulted county Supervisor Scott Haggerty in a dispute over peewee football.

As we told you Monday, Haggerty alleged that Brigham hit him repeatedly in the back of the head in an unprovoked attack after the practice for the Pleasanton football team of 10- to 12-year-old boys. Haggerty said head coach Brigham had fired him two days earlier as the assistant coach, and was angry over allegations that he had leaked plays to an opposing team.

Deputy District Attorney Ronda Theisen said Tuesday that "Mr. Brigham has a version that differs from the version provided by Mr. Haggerty, but that will be taken into consideration as our office reviews all the information available."

Coffee talk: Once again, former San Francisco Mayor Willie Brown's election-morning breakfast was a sellout, with Gov. Arnold Schwarzenegger and three would-be successors - Jerry Brown, Steve Poizner and Tom Campbell - joining 870 of the town's biggest politicos, lobbyists and donors.

Arnold got off the best line of the day: "I've been here four minutes and no one has shouted, 'Kiss my gay ass!' "

EXTRA! Catch our blog at www.sfgate.com/matierandross.

In Business: Newsom is missing a scheduled speech at the Urban Land Institute conference in San Francisco. D1