The coloring, shading, and the details are certainly convincing. I like how the snowflakes are just blurry circles but I can see that's certainly an intended artistic effect. The composition is a bit unintuitive for me though.
As far as I've read into composition, it's generally a good idea to not split an image in half by placing the horizon in the center. The logic behind that rule is to clearly emphasize an area. The horizon can be placed low to emphasize the sky, or the horizon be placed high to emphasize the landscape. The composition here has been split into two equal parts to the ground and the sky gets equal importance. This piece is certainly helped by having Celestia as the big emphasis in the piece but I think we can go farther. Celestia's face is still placed in the middle of the piece which does result in a less interesting composition from feeling symmetrical. Asymmetry is often more interesting.
Rules like that can be broken, but I am not sure if I can say this instance of bending the rules is effective. I feel that the space on the bottom of the piece isn't necessary. The framing is also making Celestia's neck appear very, very long. We can probably crop out much the bottom, but also a bit on the top and move the moon down... I think. Hopefully, that could result in a more interestingly arranged composition.
Other little things I catch is the very top of the image lacking any snow, which takes away from the piece's believability.
And one last, small funny observation... snow lowers visibility so it's kinda funny to see a clear night sky... while it's snowing. Probably artistic effect though.
As an admin of , I feel this piece falls a bit short from getting its full potential because of the needlessly symmetrical composition. This piece is one that feels a bit on-the-fence for me, but at the very least, coloring and anatomy (aside from the neck) is pretty convincing to me so I definitely see merits to this. At the time of writing though, only time will tell to see how other admins feel about this.