August especially has been very quiet with no named storms; and it's been 51 days (on August 23) and counting since the last named storm in early July - the third longest intra-seasonal hiatus on record. The strength of the sub-tropical high has helped to subdue activity, causing more of a NE'ly flow across the southern North Atlantic, with a band of cooler water edging towards the northern side of the main development region (MDR), a greater amount of shear than is favourable, and a more extensive and persistent Saharan Air Layer (SAL), the dustiness and dryness of which has been inhibiting development. As the shear decreases and the SAL diminishes, there should be the sort of uptick in activity that one would normally expect during a La Niña episode, given otherwise extensively anomalously high SSTs in the MDR. Initial expectations have been adjusted down but we are yet to reach the peak of the hurricane season, which occurs during September and continues through to November 30th.
14-21 named storms, per NOAA, doesn't sound an unreasonable range even now, as long as conditions do indeed change and we star to see some activity by late August / early September. That's a wide spread, though, and I doubt there'll be more than 16-17.