In the run-up to Christmas, online shopping continues to be strong.

Online sales are up nearly 18 percent to $110.6 billion from Nov. 1 through Wednesday, compared to the year-ago period, says Adobe Analytics, which tracks online spending.

Adobe expects the service allowing online shoppers to pick up at physical stores to be robust on Saturday as shoppers look for other alternatives to avoid long lines. The Saturday before Christmas is considered the second busiest day for store traffic after Black Friday, according to ShopperTrak, a technology firm. For the season to date, the buy online-pick up service is up 47 percent compared to the year ago-period, Adobe says.

Adobe predicts online sales for the two-month period will reach at least $126 billion, surpassing its original forecast of $124.1 billion.