Rose Season stood at the threshold of her sister's bedroom and silently watched the shadows of an oncoming storm stretch like plum-coloured talons across the empty bed. A great gust of icy wind from Lake Michigan howled at the windows.
1) Calling your introductory and therefore likely-to-be-major character Rose Season ensures that the reader will not be able to take her seriously. You might as well have called her Cherry Season, or Rose Blight.
2) By 'at the threshold' do you mean 'in the doorway', which is more concrete (whereas 'at the threshold' is often used figuratively) and therefore easier for the reader to visualise the scene? [Reader thinks: 'Ooh look, a door', but probably not 'Ooh look, a threshold.']
3) 'Silently' is redundant. Presumably if Rose were not silent then she would be talking, and there would be dialogue.
4) Shadows are not plum-coloured, indeed they are not any colour, just a blockage of light. If you mean that the clouds are plum-coloured, say that.
[Here an internal warning is sounded to the reader: this writer apparently cannot think her way out of a paper bag and presumably neither can her editor -- either that, or her editor couldn't persuade her to change it. Either way, the horrible prospect of 445 pages of woolly thinking stands before one.]
5) Talons are not plum-coloured, either. Mixed metaphor.
6) Where there is a talon-shaped shadow, it is almost always the shadow of a talon, or, more usually, several talons, since talons tend to occur in groups. It's very rarely the shadow of a cloud. You are thinking of horror movies, or Foghorn Leghorn cartoons with chicken hawks in them.
7) You need to get rid of at least one of 'great', 'icy' or 'howled'. Three exclamatory adjectives in one short sentence is at least one too many, and in any case all three are clichés.
8) Do gusts howl? Are gusts not, rather, more inclined to bang?
9) And in any case, wind is by definition a thing in motion, but in order to howl at a window, don't you need to stand still at it?
First paragraph FAIL.