As I've done the past few years, I've looked at the data from the past several years including when the ad was leaked for some popular stores and what date Black Friday fell on each year. Based on these numbers and this year's Black Friday date (November 23rd), here is the "average" day you can expect these ads this year:
October 31: Dell Home, Ace Hardware
November 5: Sam's Club, Kohl's, Sears
November 6: Target, JCPenney, Meijer
November 7: Walmart, Best Buy, Macy's, Costco
November 8: Staples, CVS Pharmacy, Walgreens
November 9: Michael's, Bass Pro Shops
November 10: Dick's Sporting Goods, GameStop
November 12: Lowe's, Old Navy
November 14: Home Depot, Menard's
November 23: Black Friday 2018
You can go back through the last 12 years to see the leaked dates for many stores here: http://blackfriday.gottadeal.com/Dates
This year Black Friday falls on the earliest possible date, the 23rd. Next year it goes back to the latest possible date, the 29th.
Of course you may remember that the last few years we had a crazy 2-day periods that saw ads from nearly all the big stores all released right after each other. I expect something similar this year around November 5-7 (and the data above backs it up), so be prepared.