NEW YORK - Americans returned to stores for the 'Black Friday' kickoff of the holiday shopping season, but online data shows that consumers have been spending big for weeks amid worries over shortages.

The day after the U.S. Thanksgiving celebration is the traditional start to the holiday shopping season, and normally sees Americans line up outside stores before they open to clinch deals on popular items.

After the pandemic kept crowds away last year, many shoppers were out in force Friday, a sign of how COVID-19 vaccines have returned life in the United States to something closer to normal.

'I just wanted to make sure that this Christmas was a good Christmas for all my friends and family,' said a masked Sylvia Gonzalez as she waited in line outside the jewelry chain Pandora in New York.

But even before retailers opened their doors early Friday morning, e-commerce shoppers in the United States had already spent $76 billion since early November, up more than 20% from the year-ago period, according to data from software company Adobe, which has projected somewhat fewer promotions this year in light of rising costs.

The jump has added to companies' optimism about the season, suggesting some shoppers heeded calls from businesses to purchase items early this year after port backlogs and other logistics problems sparked worries that popular goods would be in short supply.

Toys led the buying spree, with Adobe pointing to actions by 'anxious parents increasingly aware of supply chain challenges.'

The National Retail Federation projects overall spending could rise as much as 10.5% to $859 billion.

Nonetheless, out-of-stock listings online are up 261% compared with two years ago, according to Adobe.

Item in hand

Retailers and market watchers are broadly optimistic about the holiday shopping season in light of low unemployment and relatively strong household finances due in part to pandemic stimulus bills enacted by the government.

Countering those positive trends are lingering supply chain problems, spiking consumer prices that have affected household staples such as food and fuel, and the COVID-19 pandemic, which is still far from over.

On Friday, stock markets worldwide tumbled on worries that the latest strain of the virus found in South Africa could derail the global recovery.

Reminders of the pandemic were visible throughout shopping districts in the New York borough of Manhattan.

Signs at Macy's reminded customers to keep 2 meters apart, and pop-up COVID-19 testing sites were positioned outside stores where mostly masked crowds were large, but not as sizeable as before the pandemic.

'In 2018, it was more like the New York you heard of,' said German tourist Ilke Zienteck. 'Now, it's a little bit like a small town.'

Still, the hum of customers inside shops suggested that many had adjusted to the 'new normal' of pandemic living.

There were obvious gaps at some stores. At a Best Buy near Grand Central Station, a shelf of Apple accessories was almost completely empty, while the camera bags section had few remaining offerings.

Other chains like Victoria's Secret and Foot Locker have acknowledged shortages of some choice products.

Taylor Schreiner, a digital research expert at Adobe, expects more consumers to order online and pay for expedited shipping, or pick up goods at stores.

'It's not just because people want it quickly,' he said in an interview. 'Having the item in hand is the surest way to have the gift for the person.'

January glut?

An emerging worry in the industry is that retailers will be stuck with goods originally intended for the holidays but that don't arrive until January.

Macy's is generally canceling orders for items with a Christmas motif but plans to keep other items if they are cold-weather-oriented and could sell later in the winter, executives said earlier this month.

Gap Chief Financial Officer Katrina O'Connell said the apparel chain was planning to hold some items for next winter.

'If we think items are going to be too late for the holiday season, we won't put them in stores or online and have them generate markdowns,' she said earlier this week on a conference call with Wall Street analysts. 'We'll hold them for next year.'

Gap has been one of the companies hardest hit by supply chain problems due to lengthy factory shutdowns in Vietnam caused by the country's COVID-19 restrictions, which contributed to a loss of some $300 million in sales in the most recent quarter.