B737-800 FLT CREW PERFORMS A MISSED APCH WHEN ENCOUNTERING HAZARDOUS WX CONDITIONS ASSOCIATED WITH TSTM ACTIVITY ON ILS APCH TO RWY 9 AT IAH; TX.

Narrative

APCHING IAH FOR LNDG ON RWY 9; WE OBSERVED NUMEROUS CELLS ON RADAR IN THE ARPT AREA. WE OBSERVED 1 CELL SITTING 10 MI W OF THE FIELD AND JUST S OF THE LOC TO RWY 9. THIS CELL WAS OF PARTICULAR CONCERN TO US BECAUSE OF ITS PROX TO THE LOC. THE CTLR VECTORED US AROUND THIS STORM AND ADVISED US THAT NUMEROUS PRECEDING ACFT HAD RPTED SMOOTH RIDES WITH RAIN ON THE APCH. NO WINDSHEAR WAS RPTED. WE ACCEPTED CLRNC FOR THE ILS TO RWY 9 AND ENTERED MODERATE RAIN AT 4000 FT ON THE APCH. IT WAS LOUD IN THE COCKPIT AND WE WERE BUSY. A JET AHEAD OF US; WHO I BELIEVE HAD BEEN CLRED TO THE TWR FREQ; CAME BACK ON THE FREQ AND TOLD THE CTLR NOT TO SEND ANY ONE ELSE THROUGH THAT AREA. I DIDN'T HEAR THE FULL RADIO CALL. THE CTLR ADVISED US THAT THE PRECEDING ACFT HAD DISCONTINUED THE APCH AND ASKED IF WE WERE GOING TO CONTINUE. THE CAPT ELECTED TO CONTINUE THE APCH. I DID NOT COMMUNICATE MY RESERVATIONS TO THE CAPT AT THIS TIME. THE RAIN WORSENED TO VERY HVY AND I THOUGHT I HEARD EITHER A PREVIOUS ACFT MENTION HAIL. I TOLD THE CAPT I THOUGHT WE SHOULD GO AROUND. HE AGREED AND I INFORMED ATC OF OUR DECISION. SOMEHOW DURING THE MISSED APCH; WHILE TRYING TO ADJUST MY RADAR; I INADVERTENTLY SELECTED THE XPONDER TO 'OFF' WHICH INCREASED AN ALREADY HIGH WORKLOAD. WE INFORMED ATC OF OUR NEED TO SET UP QUICKLY FOR AN APCH TO RWY 27 OR DIVERT. ATC GOT US INTO RWY 27. I SHOULD HAVE COMMUNICATED MY SURPRISE AND DISCOMFORT WITH THE CAPT'S DECISION TO CONTINUE IMMEDIATELY.