  Magnetic active regions on the Sun are harbingers of space weather events.
Understanding the physics of how they form and evolve will improve space
weather forecasting. Our aim is to characterise the surface magnetic field and
flows for a sample of active regions with persistent magnetic bipoles prior to
emergence. We identified 42 emerging active regions (EARs), in the Solar
Dynamics Observatory Helioseismic Emerging Active Region survey (Schunker et
al. 2016), associated with small magnetic bipoles at least one day before the
time of emergence. We then identified a contrasting sample of 42 EARs that
emerge more abruptly without bipoles before emergence. We computed the
supergranulation scale surface flows using helioseismic holography. We averaged
the flow maps and magnetic field maps over all active regions in each sample at
each time interval from 2 days before emergence to 1 day after. We found that
EARs associated with a persistent pre-emergence bipole evolve to be, on
average, lower flux active regions than EARs that emerge more abruptly.
Further, we found that the EARs that emerge more abruptly do so with a
diverging flow of $(3\pm 0.6) \times 10^{-6}$ s$^{-1}$ on the order of 50-100
ms$^{-1}$. Our results suggest that there is a statistical dependence of the
surface flow signature throughout the emergence process on the maximum magnetic
flux of the active region.
