this is one of those systems that's going to be close as far as classification. it's forming in a competing ridge/shear environment with mid-level dry air infringing on it's southern and western flank, so whatever may develop will be lopsided and slow to strengthen. gradient alone will probably generate gale winds.. if the nhc decides to classify it when recon gets there tomorrow they may well go with a subtropical cyclone, as the latest twd suggests. of course if they get a warm core temperature at flight level and a tight vortex.. sheared convection or no, it's a tropical cyclone. but then i don't get to decide these things. since it appears to be headed further up the carolina coast than was earlier surmised, it will get a longer stretch over water and probably not come ashore until sunday morning. i have a feeling that it will be turning west and decelerating after midday tomorrow, so it may even be out there until midday sunday. later yet if it stays to the east like arlene did... of course then it's one of those bandwagon outer banks systems. near the shoreline water temps fall to borderline, but for a weaker or hybrid system i really don't think the 80F/27C rule holds up. a true hurricane will even do OK for a time over subpar ssts in a baroclinic environment as it converts to extratropical.
HF 0515z25june