Actually, if anything, the NHC has been perhaps a bit conservative this year with what Invests they have upgraded to an officiated tropical cyclone. There were so far two Invests I have tracked thus far which I would not have batted an eye had they been designated a TC officially and in real-time by NHC (one of them arguably qualifying as a TS, in fact).

In addition to the two Invests I mentioned above, there is reason to believe that Hermine was a Cat 1 hurricane into and/or just after landfall, and also that Alex had attained minimal Cat 3 heading into landfall. In fact, at 947mb, the min central pressure in Alex into landfall was at a level very often associated with Category 4 hurricanes.

Now as to the three features currently highlighted by the NHC for potential development, one, Invest 93L, is in reality probably already a tropical depression (and currently listed as a 90% probability of an upgrade within 48 hours - again, a very conservative call).

Another, Invest 92L, currently highlighted for a 60% chance of becoming a TC, is probably about spot on. While not yet a tropical cyclone, it has the kind of internal and external preconditions for TC development that easily warrant a forecast of about 60% chance of development over 48 hours.

The final area is flagged for a 10% chance of further development. Again, this seems reasonable given how soon this feature is likely to become entangled with an approaching front.