The trade war could determine how much holiday shoppers spend this year, the National Retail Federation said Thursday morning.

Citing "uncertainty over trade" as a potential drag on the season, the trade group estimates holiday retail sales will grow between 3.8% and 4.2% this year, excluding automobiles, gasoline and restaurants. That equates to sales of between $727.9 billion and $730.7 billion, or above-average growth.

Holiday retail sales have climbed an average of 3.7% over the past five years. However, NRF's sales range sits below some other forecasts from retail industry consultants, which are calling for growth of upward of 5%.

NRF also on Thursday called attention to a growing gap between the winners and losers in the industry ahead of this holiday season, following a recent slew of bankruptcy filings.

"It's getting a little more challenging out there," NRF CEO Matt Shay said during a media call, adding that the retail industry isn't seeing "universal growth." The winners, he said, are the ones investing in their supply chains and making shopping as convenient as possible.

Teen apparel retailer Forever 21, for example, on Sunday evening filed for bankruptcy and plans to shutter roughly 180 stores. Department store chain Barneys New York filed for bankruptcy in August. That's amid a wave of announced store closures in the U.S., many of them in shopping malls, which are set to eclipse a record this year. So far in 2019, major retailers announced plans to shutter 8,558 stores in the U.S., while opening 3,446, according to a tracking by Coresight Research.

But an ongoing trade war remains the biggest headache that could impact this year's holiday sales. The U.S. and China are set to resume trade talks later this month.

"There has clearly been a slowdown brought on by considerable uncertainty around issues including trade, interest rates, global risk factors and political rhetoric," Shay said. "Consumers are in good financial shape and retailers expect a strong holiday season. However, confidence could be eroded by continued deterioration of these and other variables."

In 2018, according to NRF, holiday sales climbed just 2.1%, missing expected growth of between 4.3% and 4.8%. A rocky stock market was called out for weighing on consumer spending, particularly among wealthier shoppers.

NRF has, meanwhile, been a loud voice for retailers arguing against additional tariffs taking effect. Shay said last month, "This trade war has gone on far too long, and the harmful consequences for American businesses and consumers continue to grow."

The group expects that tariffs will lead to higher consumer prices, which ultimately hurt consumer spending.

"There are probably very few precedents for this uncertain macroeconomic environment. ... There are many moving parts and lots of distractions that make predictions difficult," NRF's chief economist, Jack Kleinhenz, said Thursday.

NRF said a September survey of 7,419 consumers over the age of 18 found 79% of people were concerned about tariffs leading to price hikes and impacting their shopping.

It said it's expecting online and other nonstore sales in 2019, which are included in its total holiday sales forecast, to climb between 11% and 14%, amounting to between $162.6 billion and $166.9 billion.

NRF is also calling for retailers to hire between 530,000 and 590,000 seasonal workers this year, compared with 554,000 in 2018. Macy's on Thursday announced it plans to hire 80,000 temporary workers for the holidays, in line with its goals in 2018. Target has said it plans to hire 130,000, up from 120,000 last year. Kohl's is aiming for 90,000, matching its hiring targets in 2018.

With an incredibly tight U.S. labor market, however, many of these companies are having to get creative in offering better perks, or pay out higher wages, to retain talent.