trend in recent years has been for a great deal of activity. some seasons are spread out, some have most systems occuring over a 30-40 day period. 1995 and 2001 each had a pair of active periods. what we have right now is enso neutral... shifting towards positive but only slightly so. mjo waves will most likely define the active periods this year, as has been the trend of recent years.
i think a lot of people put too much stock in how warm/cold the east atlantic is. a great deal of the systems that affect north america originate as waves down there, but not all of them develop at 30w. in fact many get quite a bit further west before doing so.. higher ssts out there usually means storms peak and recurve well out to sea. how active the upper westerlies in the deep tropics has more to do with systems developing out there than does ssts, hitting the threshold early often means nothing as the atmosphere can't support what the water temps can.
warmer ssts in the subtropics are the more likely source of increased early season activity.. the usual suspects this time of year into july are of extratropical origin, or waves energy that gets turned up into a mid-latitude system. and we've got plenty of above normal sst patches near 30n across the atlantic.
HF 2311z17june