AIR CARRIER; EXECUTING A GAR; ENCOUNTERED TURB AND SUFFICIENT UPDRAFT TO PREVENT THE FLT CREW FROM LEVELING AT THE ASSIGNED ALT.

Narrative

HELD FOR 45 MINS OVER HEATR INTXN ON UKW 9 ARR AND THEN WAS NOTIFIED THAT DFW WAS 'NOW OPEN' AND ACCEPTING ARRS. (TSTMS HAD CLOSED THE FIELD.) ARPT WAS RPTING 53 KT GUST WHILE WE WERE ON DOWNWIND; SO WE AGREED THAT WE WOULD NOT LAND IF THE WINDS DID NOT IMPROVE AND ALSO THAT THE CAPT WOULD FLY THE APCH. WE XFERRED CTLS AT AROUND 11000 FT. WINDS/GUSTS LESSENED AND CAPT FLEW APCH TO RWY 36L AT DFW. WIND SHIFT FROM PASSING TSTM CAUSED TOO MUCH OF A TAILWIND TO LAND TO THE N. AT APPROX 1800 FT MSL; CAPT EXECUTED A GAR TO 3000 FT MSL. NOTIFIED CAPT WITH 1000 FT TO GO CALL OUT; AND APCHING 3000 FT AGL; I CALLED OUT 3 TIMES TO LEVEL OFF AND TOUCHED HIS HAND TO SIGNIFY TO LEVEL OFF. CAPT LATER STATED HE HAD 10 DEGS NOSE DOWN AND IDLE THRUST AND WAS UNABLE TO LEVEL AT 3000 FT. I NOTIFIED ATC THAT WE NEEDED A HIGHER ALT AND THAT IT WAS 'VERY ROUGH AT 3000 FT' BUT BY THIS TIME WE WERE APPROX AT 3600 FT. AS WE WERE CORRECTING TO OUR ASSIGNED ALT OF 3000 FT; ATC RESPONDED WITH A CLB TO 5000 FT. FLEW OUTBOUND TO THE N AND RETURNED TO AN UNEVENTFUL LNDG ON RWY 18R. WE DISCUSSED THE EVENT FURTHER ON THE GND AND THE CAPT BELIEVED THAT WE WERE CAUGHT IN AN UPDRAFT WITH MODERATE TURB FROM THE PRECEDING TSTM. NO TA/RA OCCURRENCES.