You can check the links given on this post :
http://www.secret-japan.com/forum/viewtopic.php?t=101
At the bottom, there are 4 links of web sites that give the hanami previsions for all Japan.
Anyway, the period you are talking about is probably perfect: it is best to see the cherry blossom immediately when it start. The trees are getting completely white surprisingly fast (usually in 48-72 hours), but if you wait and there is some rain, then many flowers will be washed away - and from that point, it is really not as interesting.
Finally, Kyoto and Nara are very close and have similar climat, I would say that hanami period should be the same. But I can not confirm that.
sanji