My site displays the highest 30 second sustained flight level wind with the wind barbs in Google Earth. The HDOBs also have 10 second flight level wind gusts. Official advisories are supposed to be 1 minute sustained winds at the surface. When there is no SFMR, you have to estimate what it might be at the surface. Of course even when SFMR is available it is not a direct measurement but estimated. Additionally, the SFMR is 10 second gusts. The NHC often seems to use the 10 second flight level wind gusts and then a reduction factor from that, perhaps assuming that the plane did not sample the absolute highest wind, or use the 10 second SFMR even though advisories are supposed to be 1 minute sustained wind.
And that is the highest wind noted in the vortex message.
I'm not exactly sure what part of it made them decided to go to 115mph, but it was probably about 90% of the flight level wind since they don't have SFMR on the Air Force flight at the moment.