Steamy South Florida grew hotter yesterday as ballot counters in Broward and Palm Beach counties sprinted toward today's 5 p.m. deadline for completing manual recounts of contested presidential ballots.

As demonstrators faced off in the streets and national political leaders scrutinized ballot counters' work, canvassing board members in the two counties continued to try to determine the will of voters by examining tiny marks on punch ballots, sometimes using magnifying glasses.

With Secretary of State Katherine Harris ready to certify the state vote this evening, it appeared unlikely that Al Gore would gain enough votes through hand counts in the state's two most heavily Democratic counties to overcome a 930-vote edge in Florida held by George W. Bush.

In Broward County, Gore picked up 563 votes as the three-member canvassing board finished its review of 2,422 contested ballots at about midnight.

But supporters of the vice president were sorely disappointed by results in Palm Beach, where canvassers used a stricter standard for recording so-called dimpled chads.

Republican and Democratic observers say Gore has a double-digit net gain in Palm Beach. Republican observers listed Gore's unofficial gain at 86 votes with 428 of 637 precincts reporting. Earlier, Democratic observers listed Gore with a slightly smaller gain.

At 2 a.m. the count was continuing and no new numbers were available. Overall, the Associated Press reported early this morning that Gore still trailed Bush by 464 votes, not including any votes from Palm Beach.

The numbers are far from what the Democrats expected in Palm Beach when they called for this hand recount of all precincts plus absentee ballots. The count was precipitated by a 19-vote net gain for Gore after 1 percent of the vote was counted by hand two Saturdays ago.

And, as the vote counting progressed yesterday, it started to seem improbable for the three-member canvassing board to finish on time. At midnight, there were 4,400 questionable ballots awaiting a ruling from the board. The board had counted 3,000 ballots yesterday. The entire 15-hour day Friday, the board went through 1,868.

So the counting has become a race against an inflexible deadline -- 5 p.m. today, the time set by the Florida Supreme Court last Tuesday that permitted the hand count to continue.

Judge Charles Burton, the chairman of the Palm Beach County Canvassing Board, swears the three-member panel that includes elections director Theresa LePore will get the job done. If it doesn't, he said, it will send what's done to Tallahassee.

"If we've got to stay all night tonight, we will," he said in the afternoon. "We've been working too hard and too long to not finish."

To be done before the deadline, they'd have to count more than 250 ballots an hour all night long, without meal breaks, bathroom breaks or the all-important -- for this group at least -- cigarette breaks. Not to mention that LePore needs to sign off on the already counted precincts to have final tallies available for certification in Tallahassee.

Vocal bands of Bush and Gore supporters gathered yesterday in both counties, and access to the Broward courthouse and Palm Beach emergency operations center became a hot commodity. A steady stream of national and local political figures also arrived throughout the day, each trying to out-spin the last.

"This is one of the most important things happening in the world today," said New Jersey Gov. Christine Todd Whitman, a Republican.

While Republicans relied on a cadre of governors to deliver their message that shifting standards by the canvassing boards compromised the integrity of their totals, the Democrats countered with a contingent led by Sen. Barbara A. Mikulski, the Maryland Democrat, who urged calm as the vote count reached its final stages.

"For all of those who wish to be disruptive, I ask you to restrain yourselves for the next 24 hours," Mikulski said.

Tensions bubbled in Fort Lauderdale over a final box of ballots that contained about 500 questionable absentee ballots. A squabble over whether the ballots should be counted led to a Republican lawyer's being ordered out of the counting room and dueling news conferences between the GOP and Democrats.

Republicans argued that the absentee ballots should be left out of the hand count, because canvassers could not apply the same standard as those marked in voting booths.