This could be the best holiday season in more than a decade

Don't count out the holiday season just yet.

After a larger-than-usual last-minute shopping boost, followed by a solid start to the post-Christmas period, one well-known retail analyst is lifting his forecast for the critical spending period.

Craig Johnson, president of Customer Growth Partners, now expects holiday sales to increase 4.9 percent this season. That's up from his previous estimate of 4.1 percent growth.

If achieved, this rate of growth would be the most robust increase in more than a decade. In 2005, sales rose 6.1 percent year over year, Johnson said.

In addition to the last-minute spending surge, stronger-than-expected economic fundamentals, record stock prices, double-digit online sales growth and chilly temperatures contributed to the firm's revision.

"This was the strongest Christmas Eve we've seen in a long time," Johnson said. He added that Monday was the "strongest Dec. 26th we've seen in years."

During the final shopping crunch, retailers benefited from Christmas falling on a Sunday. That gave consumers an extra Saturday to complete their shopping. The industry's momentum continued into Monday, which was a federal holiday, Johnson said.

"We had a major inflection point in retail demand occurring a few days after the election ... [and] things have steadily gathered steam ever since then," he said.

Although foot traffic was down throughout the season — most notably at the malls — shoppers that did head out to the stores made purchases more frequently, Johnson noted. Popular products included over-the-knee boots, Hatchimals and televisions.

Still, not everyone is as bullish. After a softer-than-expected monthly retail sales gain in November, many on Wall Street grew concerned that the season would fall short. Those concerns were exacerbated by reports that the lulls typical of early December were more pronounced than usual, as shoppers held out for retailers' last-minute deals.

In a note to clients a few days before Christmas, Retail Metrics President Ken Perkins wrote that the annual slowdown after Black Friday was more noticeable than the prior year. He added that Super Saturday wasn't enough to make up for declining foot traffic from earlier in the month.

Similarly, The NPD Group found that dollar sales in the first month and a half of the holiday season were 4 percent behind the prior-year period. They were even lower as compared with the previous year during the sixth week.

"The holiday lull of week six is deeper than retailers want, but they drove it with deeper and deeper discounts," NPD analyst Marshal Cohen said at the time.

Despite all the season's ebbs and flows, the National Retail Federation is sticking with its prediction that sales will meet or exceed its projected 3.6 percent growth this holiday season. It stood by its estimate after the Commerce Department's November report, noting that excluding automobiles, gas stations and restaurants, sales rose 5 percent over the prior year.

AlixPartners, which is calling for a lift of 3.3 percent to 4 percent this holiday, is also standing by its forecast. Noam Paransky, a director in that firm's retail practice, told CNBC on Tuesday that holiday sales will likely fall in the middle of its predicted range, or slightly above the midpoint.

Demand has been particularly strong for consumer electronics and cold-weather apparel, he noted.

"I went to the beach yesterday. [It was a] beautiful day and the beach was pretty empty," said Paransky, who lives in Sarasota, Florida. "Then I drove by the mall, and the mall was jampacked."