1 Frosty tiara wearer; feel nostalgic for powder. (4, 4)
7 Kill Bill actress inhuman? (3)
8 Knuckle strike comes back as even. (3)
10 Doris shatters; night ends with mangled bakery ads. (9)
12 French here in broken icicle. (3)
13 Magical lines in earth at end of alley. (3)
14 I, agent, got mixed up dining. (6)
17 Sounds like you see the middle of a duck. (2)
18 Correction to "I see a osprey!"; common to the Bangles, Kant, and Manet. (2)
19 Manner in which data is sometimes displayed; remove the slang for brother from barograph. (1, 5)
21 Popular dog command echoes as McCourt novel. (3)
23 Drag part of a head or sack. (3)
24 Winfrey triumphs at sweeps! Turn wino harps on and celebrate! (5, 4)
26 Frequent cry at sports game of what we are; no I really mean it. (2, 1)
27 Formerly; pull special cereal letter away from a major leg joint. (3)
28 Canine forests of ornamental shrubs. (8)

1 What comes with the thaw; wet dirt to spice up time of year. (3, 6)
2 Declaration of confused aim is part of climate. (3)
3 Spit it out; with 'ain't so' part of famous phrase. (3, 2)
4 Leap, defrost; soon groggy thrips gnaw the new green shoots of a season de-iced. (6, 4)
5 Sexy part of moral in the beginning of orange lips. (4)
6 Snap out of it sort of call; funeral party isn't down. (4-2)
9 Mental conditions; pump up rubber tubes for water with shared H. (9)
11 Prchristian spook agency acronym? 3 Banded Italian + 1 of 7 + Caesar's 1 + Good grade. (4)
15 A modern musical device; messed up, paid no attention to this tuneful gimmick. (2, 1-3)
16 Increase plant, take the inn out of ingrown. (4)
20 A disreputable sot; pull early director Griffith out a window. (1, 4)
22 Tripartate group gets separated and then reformed in riot. (3)
25 Actor Beatty comes back as snug place for animal. (3)