west·er·ly 
(wĕstər-lē)
(wĕstər-lē)adj.
1. Situated toward the west.
2. Coming or being from the west: westerly winds.
n. pl. west·er·lies
A storm or wind coming from the west.
[Middle English, from wester, western, from Old English westra; see wes-pero- in the Appendix of Indo-European roots.]
wester·ly adv.