But retailers are bracing for inventory shortfalls, as well as scarce labor at ports, driver shortages, rising warehouse expenses and higher prices. So they are encouraging shoppers to open their wallets early this year, inducing fear by highlighting what retailers describe as "supply chain challenges," "longer delivery times" and "lower inventories," in marketing materials. Surf- and skateboard-wear retailer Zumiez (NASDAQ: ZUMZ ) Inc's website features a banner that reads: "Don't let out-of-stock items and shipping delays screw up your plans." The mall-based retailer primarily sources merchandise from Asia, Mexico and Central America. It did not immediately return messages seeking comment. Nordstrom (NYSE: JWN ), which typically brings in about 20% of its merchandise from China, on Thursday sent a holiday marketing email to customers citing "global supply chain challenges" that they said would likely put a damper on holiday shopping plans.