NEW YORK (CNN/Money) - Shoppers flocked to stores for last-minute Christmas gifts Friday but retailers were wondering whether it would be enough to rescue a lackluster holiday sales season.

A shopper buying a gift card at the Rimrock Mall in Billings, Mont.

The late shopping rush was complicated by heavy snow in the Midwest.

Overall the retail industry has projected a 4.5 percent sales gain for the season, though many inside and outside the industry are wondering if sales will end up meeting those forecasts.

"Snow always wreaks havoc on procrastinators but it doesn't deter those who absolutely have to get their shopping done," Marshal Cohen, chief retail analyst NPD Group, a market research firm, said Friday.

"The last seven shopping days before Christmas are very, very important to retailers and you don't want to lose sales momentum during that period."

Cohen expects holiday sales to grow 3 to 4 percent. "The season will be just OK -- not something to get overly excited about," he said.

Holiday shopping is crucial for retailers, accounting for 50 percent or more of their annual sales and profit. Industry observers had expected merchants to benefit from two additional shopping days between Thanksgiving and Christmas.

Gary Autry doing his traditional last-minute shopping at Proffitt's in Chattanooga, Tenn.

"With Christmas Eve falling on a Friday, sales have the potential of being very intense," said Richard Hastings, senior retail analyst with Bernard Sands.

"Many people who work will leave early to shop. Others have the day off and could decide to go to the mall," he said.

"I think the last-minute rush will take place in stores that are conveniently located and which offer the best bargains." He said he's sticking by his projections for holiday sales to rise about 5 percent.

Heavy snow storm and icy conditions covered the Midwest Friday, making for dangerous driving conditions and hampering holiday travel plans.

The snow also meant that many gifts being shipped might not get there in time for Christmas.

"We opened our mall at 9 a.m. this morning and our parking lot is now about 80 percent full. On Christmas Eve we typically see the lot 100 percent full," said Kimberly Shadwick, spokeswoman for the Great Lakes Crossing Mall in Auburn Hill, Mich.

A shopper in New York carrying gift packages.

"The fact is the weather has certainly affected traffic trends today. We have over 8 inches of snow on the ground," Shadwick said. Retailers at the mall include Neiman Marcus, Bed Bath & Beyond, T.J. Maxx, Liz Clairborne and Marshall's.

"But we do expect the crowds to pick up by the afternoon because there are still people out there who have to buy their gifts. We saw this happen yesterday when shoppers started to come in later in the day."

Retailers nationwide were offering big discounts of 40 to 60 percent to lure shoppers. Selected items sported even bigger discounts.

The Hamilton Place Mall in Chattanooga, Tenn., saw plenty of shoppers out as early as 7 a.m.

"Some guys were with their kids who were offering advice to dads on what to get mom this Christmas," mall spokesman Jeff Odom told CNN/Money.

"Early morning crowds seemed to be looking for even greater markdowns with jewelry, electronics and perfume being everyone's go-to last-minute item," he added.

One strong spot has been Internet sales, which are up 28 percent so far this holiday season.

YOUR E-MAIL ALERTS Holidays Retail Winter Storm or Create your own Manage alerts | What is this?

Another area of strength has been luxury goods, which are selling briskly in many parts of the country.

The big transport companies said the weather would make it hard to get gifts to people by Christmas.

UPS said that some packages set for delivery Thursday and Friday may not get there by today, adding it was "optimistic" delayed packages will be delivered Monday.

"We regret any inconvenience that severe weather conditions may have caused our customers," the company said.