MD80 FLT CREW REPORTS CONTINUOUS MODERATE TURBULENCE FOR SEVERAL MINUTES WHILE FLYING THROUGH GAP IN LINE OF THUNDERSTORMS AT FL340.

Narrative

WITHIN MINS AFTER TKOF; RERTED DUE TO TSTM ACTIVITY ALONG FILED RTE. NEWLY ASSIGNED RTE: PNH J17 TBE.... LINE OF TSTMS ACROSS THE TEXAS PANHANDLE WAS THE ISSUE. CTR AGAIN RERTED US: ABI FST TCS.... THIS RERTE ADDED HUNDREDS OF MI TO OUR FLT PLAN AND WAS NOT FEASIBLE. ON A WESTERLY HDG; THE FO AND I OBSERVED ON WX RADAR A BREAK IN THE LINE OF TSTMS THAT WOULD ALLOW US TO TURN N AND HEAD TOWARDS LBB. WE GOT THE CLRNC TO DO THIS AND PROCEEDED TOWARDS THE GAP. I SAT THE FLT ATTENDANTS DOWN REALIZING THAT THE RIDE WOULD BE BUMPY. WE STAYED CLR OF THE CELLS BUT AS WE CROSSED THE LINE WE EXPERIENCED CONTINUOUS MODERATE TURB FOR 5-8 MINS. WE WERE AT FL340 WITH ENG AND WING HEAT ON AND WERE HOLDING .75 MACH. DURING THE TURB ENCOUNTER; MACH NUMBER WAS VARYING GREATLY (MACH .69 TO MACH 79.). WE RECEIVED CLRNC TO DSND TO FL320 AND THEN DOWN TO FL300 WHERE WE WERE FINALLY ABLE TO STABILIZE THE AIRSPD. WE CLRED THE LINE AND HAD A FAIRLY SMOOTH RIDE THE REST OF THE WAY. THIS IS A SCENARIO I WILL NOT GET MYSELF INTO AGAIN. A BETTER COURSE OF ACTION WOULD HAVE BEEN TO TURN AROUND AND GO BACK.