B737-500 FAILS TO FOLLOW TRACK CLRNC WHILE CIRCUMNAVING TSTMS AND ENCOUNTERING MODERATE TO SEVERE TURB.

Narrative

CRUISING FL330 OVER IOWA; MODERATE BORDERING SEVERE TURB; CIRCUMNAVING STORMS. PLANE BEING TOSSED ABOUT SEVERELY; VERT SPDS EXCEEDING 1000 FPM UP AND DOWN. FLT ATTENDANTS CALLING COCKPIT; PAX GETTING UPSET AND SICK; FO TALKING TO FLT ATTENDANTS EXPLAINING THE SIT. I WAS CLBING THE ACFT TO FL370 ON A HDG AND DEVIATING N OF STORM. THE PLANE WAS ROLLING L AND R IN EXCESS OF 30 DEGS OF BANK. THE CTLR STATED THAT I WAS ASSIGNED A HDG TO FLY WHILE IN THE CLB AND I DO NOT REFUTE THAT. I HAD BEEN GIVEN CLRNC TO PROCEED DIRECT FWA WHEN THE CTLR TOLD ME I WAS SUPPOSED TO REMAIN ON THE ASSIGNED HDG UNTIL FL370. BECAUSE OF MY EARLY TURN TOWARD FWA; I WAS SUBSEQUENTLY INSTRUCTED TO TURN L BECAUSE OF CONFLICTING TFC ALSO CIRCUMNAVING THE STORM AND TURB. I IMMEDIATELY COMPLIED WHILE STILL ATTEMPTING TO CTL THE ACFT AS IT WAS BEING TOSSED ABOUT. EVENTUALLY WE CLRED THE AREA OF TURB; AND WERE CLRED DIRECT TO FWA. I APOLOGIZE FOR THE MISCOM AND ACTION TO THE CTLR. I WAS LATER INSTRUCTED TO CONTACT CTR AFTER LNDG IN IAD; AND DID SO. IF I HAD TO EXPERIENCE THIS SIT AGAIN; I WOULD HAVE DEVIATED MUCH SOONER THAN WE DID HAD I KNOWN THE TURB WAS GOING TO BE SO VIOLENT.