Questions about this piece
What is sherpa fleece?
A knit fabric with the surface brushed and curled into small loops so it looks like the wool side of a shearling coat. It is almost always synthetic, which is why it weighs so little for how thick it looks, and the loops hold air, which is where the warmth comes from rather than from the fiber itself. This jacket uses it as the outer face, with faux leather trim running through it so the pile is not the only texture showing.
Is a fleece jacket warm enough on its own?
That depends less on the fleece than on what is sealing the edges. Pile holds air well, but air moves straight out through an open collar, a loose cuff or a gaping hem, and that is usually what makes a fleece feel thinner than it looks. This one is fully lined and has a high collar with elastic at both the cuffs and the hem, so the three places warmth normally escapes are closed off once the zip is up.
Is this jacket cut close or loose?
Loose. It is drawn as a relaxed fit with the shoulder seam sitting out past your own shoulder, which is what leaves room for a sweater underneath without the armhole pulling when you reach for something. The elastic at the cuffs and the hem takes that width back in at the wrists and waist, so the volume stays in the body instead of hanging off you. The side pockets sit in that roomy panel, so your hands go in without stretching the front.