Absolutely looks like a LIS base.
Speculating about new bases, huh? Look at this: starting on April 2nd...
(daily)
Warsaw Modlin 12:10 - Gdansk 12:55
Gdansk 13:20 - Warsaw Modlin 14:10
Warsaw Modlin 15:00 - Wroclaw 15:55
Wroclaw 16:20 - Warsaw Modlin 17:20
Logically: where this aircraft could actually be based? GDN has no based aircrafts, WRO has, but it's not coming from there. A "double W-pattern"? Don't think so. Two different aircraft making separate W-patterns? Quite unlikely, they don't fit into any existing schedules. So my guesswork's conclusion: it will be a Modlin based aircraft, doing something in the morning, going to Gdansk and back, at 15:00 after a standard 50 min. crew change performing WRO rotation.
In fact I've noticed it a few weeks ago, I'm apparently too old to become excited by that kind of observation, but if you speculate... here we go.