Do you mean 19 August this year, also known as "the day after tomorrow"?

The "great fares" you're looking for tend to have limited availability and advance purchase requirements. Sometimes that means 60 days before your travel date, sometimes just 21 or 14 days. The airlines are not in the habit of offering their lowest fares to people who "need" to fly from N. America to Europe today or tomorrow.

If an airline has lots of spare capacity a few days before a flight, you might find "last minute" bargain fares. If they exist, you'll find them using Kayak or the airlines' own sites. ExpertFlyer is great at what it does, but it probably won't help you much with your particular search.