10m - Es or tropo?

I have been on 10m WSPR since early morning (2W ERP) bue so far I have spotted PD0OHW just once at 09450z with -3dB drift at a reasonable -18dB S/N.   At 459km this could have been either tropo/aircraft or Es. This is very short ship for Es. No other signals yet seen and no-one has spotted me yet.

UPDATE 1300z: DB0ZDF (608km) spotted me on 10m at 1208z.  This is definitely Es. So far, the only person to spot me on 10m today.

UPDATE 1302z: DK6UG (633km) just spotted me on 10m. Es again.