WASHINGTON >> With an eye on the weather forecast, President Barack Obama and Republican Mitt Romney are starting a 10-day sprint to the finish line in a contest increasingly about momentum versus math.

“Let’s win this,” Romney emailed supporters today as he hopped a plane from one important state to another — Ohio to Florida.

“We’re defying odds and holding strong,” he told his backers and urged them to contribute more money to help Republicans keep up the fight.

His running mate, Paul Ryan, was out early in rainy, chilly Ohio to visit a factory in New Philadelphia, where he told voters, “You know it’s you. You know what you have in front of you. You know your responsibility.”

A huge storm barreling toward the East Coast and some battleground states had both campaigns adjusting travel schedules and canceling events. Even at this late date in the campaign, neither side wanted to risk the appearance of putting politics ahead of public safety.

The president pressed on with a campaign trip today to New Hampshire but held a conference call with administration officials about emergency preparations from aboard Air Force One.

Campaign spokesman Jennifer Psaki said the Obama team is continuing to promote early voting as something that provides flexibility for busy families but she added that “safety comes first and that’s the case with early voting as well.”

An email announcing that Vice President Joe Biden’s rally today in coastal Virginia Beach, Va., had been cancelled stated that the change was “being taken out of an abundance of caution to ensure that all local law enforcement and emergency management resources can stay focused on ensuring the safety of people who might be impacted by the storm.”

Romney canceled a rally in Virginia Beach that was planned for Sunday, and aides said they were also considering scrapping two other events elsewhere in the state. None of Obama’s campaign stops had been canceled, but he did adjust his travel schedule slightly. The campaign moved up his planned Monday departure for Florida to Sunday night to beat the storm.

One prominent Romney supporter, Gov. Chris Christie, R-N.J., said today he told the campaign he couldn’t travel on Tuesday because he wanted to keep tabs on the storm.

With the Nov. 6 election fast approaching, Obama and Romney are tied nationally. But the president still appears to have more ways to reach the required 270 electoral votes.

The Obama campaign released a new TV ad today urging Americans when they go into the voting booth to consider Romney’s plans to roll back Wall Street reforms, transform Medicare into a voucher-like system and reduce spending on education while at the same time cutting taxes for the rich. The spot will air in Florida, Iowa, Ohio and Virginia, all key battleground states.

The Republican nominee is trying to seize the momentum and turn a wave of GOP enthusiasm into an electoral victory.

Psaki threw water on the whole idea, saying Romney’s team was “working overtime to spin that he has momentum.”

Obama’s campaign pressed forward with a get-out-the-vote effort that aides said had them leading or tied in every competitive state. The president was eschewing the lofty rhetoric of his 2008 run in favor of warning supporters that skipping out on voting could cost him the election.

“In 2000, Gore vs. Bush, 537 votes changed the direction of history in a profound way and the same thing could happen,” Obama said in an interview Friday with MTV.

Romney was switching his attention to Florida today after spending much of the week focused on shoring up support in Ohio. While the Midwestern swing state could be crucial to Romney’s re-election prospects, he also faces tremendous pressure to carry Florida, which offers 29 Electoral College votes, the most of any swing state.

Obama carried Florida by just 3 percentage points in 2008 and polls show the candidates tied.

The former Massachusetts governor was scheduled to attend three rallies, the first in Pensacola along the state’s conservative Panhandle. He then moves to suburban Orlando before finishing his day with an evening rally just outside of Tampa, the site of the Republican National Convention. Romney was to be joined at all three events by Florida Sen. Marco Rubio.

Ryan had his family in tow for the factory visit in New Philadelphia, and his 7-, 9- and 10-year-olds scampered between parts bins and heavy chains.

Nine-year-old Charlie waved the peace sign and mugged for cameras, prompting his mother, Janna Ryan, to shake her head and declare, “I don’t know where he gets it. It’s kind of crazy.”

___

Associated Press writers Philip Elliott in New Philadelphia, Ohio, and Steve Peoples in North Canton, Ohio, contributed to this report.