10m opens to the USA (after all)

Much to my surprise W4MO (7177km) running 1W from Florida, has just been spotted, by me, on WSPR at 2120z and 2128z.. After the mainly N-S propagation this came as a surprise.

With a lot of Doppler (2Hz) I wondered at first if this was coming by moving spread-F from clouds close to the equator?  We saw similar a few evenings back.  He has just spotted me (-26dB S/N) with 0Hz drift, so that is my spread-F theory gone out of the window!

Still puzzled why just W4 (Florida) call area though i.e.. only lower latitudes of the USA.