ACR LGT TRACK DEV DURING CLB S OF TYS.

Narrative

FLT WAS FILED AND PLANNED TO CRUISE AT FL330. INITIALLY CLRED (ENRTE) TO CLB TO MAINTAIN FL290. UPPER LEVEL WX; IN THE FORM OF CLOUD FORMATIONS THAT HAD APPEARANCE OF CONTAINING TURB; EXISTED IN THE AREA OF TYS. IT APPEARED THAT FL330 WOULD PROVIDE CLRNC OF CLOUDS AND TURB. CLB CLRNC TO FL330 WAS REQUESTED AND RECEIVED FROM ATL CENTER AT 30 NM S TYS; AND CLB OUT OF FL290 TO FL330 INITIATED. ACFT HAD DRIFTED SLIGHTLY R (E) OF COURSE APCHING TYS DUE TO AUTOPLT NOT PROPERLY TRACKING COURSE. WE DID NOT PICK UP DRIFT INITIALLY DUE TO OUR ATTN BEING FOCUSED OUTSIDE ON PREVIOUSLY MENTIONED CLOUDS. I ESTIMATE WE DRIFTED 2-3 NM E OF COURSE BEFORE TAKING CORRECTIVE ACTION. WHILE STILL S OF TYS VOR IT BECAME APPARENT THAT FL330 WOULD NOT CLR AREA OF SUSPECTED TURB; SO WHILE CLBING THROUGH FL32.7 CENTER WAS ADVISED THAT WE WANTED A W DEV (W OF TYS). CENTER REQUESTED TO KNOW IF WE WERE DEVIATING E. WE STATED WE WANTED A W DEV; AND ATL CENTER RESPONDED WITH A REPLY FOR US TO DSND TO FL310; FOLLOWED SHORTLY AFTERWARD BY INSTRUCTIONS TO EXPEDITE DSCNT (IN AN EXCITED SOUNDING VOICE). WE COMPLIED AND CHKING OUR TCASII SHOWED AN ACFT IN OUR 6 O'CLOCK POS; APPROX 5 MI AT FL330. ACCORDING TO OUR NAV INSTS; WE WERE NOT PRECISELY ON COURSE; BUT APPEARED TO BE WELL WITHIN TOLERANCES. CERTAINLY WE'LL EXERCISE MORE DILIGENT ATTN TO NAV AIDS IN FUTURE AND HOPEFULLY ATC WILL RETURN FROM PLACING 2 OR MORE ACFT IN A POS CREATING CONFLICT; OR THE POTENTIAL FOR CONFLICT.