I am >90% certain that if NHC doesn't name it -at some point *during* it's life cycle- 90L will be added during reanalysis as an unnamed storm.

As Bloodstar mentions above, the structure is indeed improving tonight. In fact, it is now looking like it is gradually taking on a little more *tropical* than just subtropical characteristics, especially with significantly deeper convection - as opposed to the mostly shallow convection early on - now starting to legitimately close in around the center at this hour.

In keeping with the headline of this thread, the question posed is not whether 90L is an extra-tropical storm or tropical storm, it is whether or not it is a *sub* tropical storm. For this, I would strongly suggest one reads the Glossary of NHC's Terms

This is exciting, of course! Would become the first named May storm since 1981 if bumped, yes?