Who knows - Jazz Impressions may eventually make it to WSHH, but it's been a long while since Wish has aired any unique programming on Sundays. Back in the Beautiful Music days it had Ken Lamb's "Special of the Week" from WPAT, in the early to mid-90s Charlie Gray (then of the Civic Light Opera) did "Wish on Broadway" - a salute to various musicals at 9 AM on Sundays. And, as Ken mentioned, "Nuages" was on from 10 - noon on Sundays.
You might also recall that in between the station's "Wish for Lovers" and "Delilah", there was a smooth jazz program hosted by Alan Freed (obviously not THE Alan Freed) who later became the webmaster. I forget the name of that program, but it had a somewhat short life - perhaps only lasting a year.
'JAS seems to be the home of the unique weekend programming for Renda in Pittsburgh right now.