(NEW YORK) If the beginning of the holiday season is any indication, it could be a merry mobile Christmas for shoppers.

For the first time, more people are expected to visit retailers' websites through their smartphones than via desktop computers or tablets during the first weekend of the holiday shopping season, which begins on Thanksgiving Day.

Mobile traffic during the five-day start to what is typically the busiest shopping period of the year is expected to reach 56.9 percent of total traffic, up from 48.5 percent last year, according to IBM Watson.

And even though not everyone who "window shops" via phone is going to buy, mobile sales are jumping, too. They're expected to account for 36.1 percent of online sales, up from 27 percent last year, according to IBM Watson Trend.

The bumps in traffic and sales come as retailers try to make the mobile shopping experience easier by improving their apps and adding deals. Shoppers also have gotten more comfortable browsing retailers' websites as smartphone screen sizes have gotten bigger. Digital wallets and apps that let shoppers store payment information are helping, too.

"It's very convenient," said Seth Reineke, 25, an insurance worker from Iowa City, Iowa, who plans to peruse Amazon's weekend deals from his phone. "It allows me to keep track of time-sensitive sales without being tied to a computer or having to leave a holiday event or get-together."

Overall spending this season is expected to be somewhat muted. But online spending figures are strong. Forrester predicts online sales will rise 11 percent, to $95 billion. And mobile sales are becoming a bigger piece of that pie. Forrester expects them to account for 35 percent of e-commerce this year and 49 percent in five years. That compares to 29 percent in 2014.

"There's a lot of opportunity to do 'shopping under the table' on Thanksgiving Day," said Tamara Gaffney, director of Adobe Digital Index. "In between cooking, watching football, and hanging around family and friends, there's down time to glance at the iPad and smartphone and do some shopping."

Mobile shopping still has its problems, including security concerns, sluggish apps, and hard-to-navigate websites.

But for shoppers, the convenience factor is hard to beat, says Forrester Research analyst Sucharita Mulpuru.

"While retailers may lament their low conversion rates and slow download speeds on mobile devices, shoppers still keep shopping on those devices," Mulpuru says.