MD-83 CAPT WAS REQUIRED TO TAKE CTL OF THE ACFT TO PREVENT THE FO FROM DRIFTING OFF THE L SIDE OF THE RWY.

Narrative

IT WAS AT THE END OF A VERY LONG DAY. WE WERE DEALING WITH WX; ATC; AND PAX CONCERNS. THE DUTY DAY WAS ABOUT 12 HRS LONG. THE PREVIOUS LEG WAS 5 HRS ENDING IN A GATE WAIT OF 1 HR IN DFW. THE LEG IN QUESTION WAS DFW-STL ARRIVING AT EARLY MORNING. THERE WERE SCATTERED SHOWERS IN THE STL AREA AND THE FO WAS FLYING THE ACFT. WE INITIALLY SET UP FOR THE RWY 30R APCH TO STAY OUT OF THE WX. HOWEVER; ATC SAID IT LOOKED OK TO FLY THE RWY 12L APCH. WE INITIATED THAT APCH; BUT DISCONTINUED BECAUSE OF WX INFRINGING ON THE FINAL APCH COURSE. WE THEN SET UP FOR THE RWY 30R; BUT BECAUSE OF HURRIED VECTORS; WE WERE NOT ABLE TO PROPERLY SET UP FOR THE APCH; SO WE DISCONTINUED THE APCH. WE CAME BACK OUT FOR ANOTHER RWY 30R AND WERE STABILIZED FROM THE OM INBOUND. WHEN WE SWITCHED TO TWR; WE WERE TOLD IT WAS STARTING TO RAIN; BUT VISIBILITY WAS STILL 1 1/2 MI. WE COULD SEE THE RWY FROM JUST INSIDE THE OM. THERE WERE NOT WINDSHEAR ADVISORIES AND THE WIND WAS 210 DEGS AT 6 KTS. ON SHORT FINAL WE STARTED GETTING RAIN AND VISIBILITY WAS DETERIORATING TO ABOUT 3/4 MILE. WHEN THE FO STARTED TO FLARE; HE STARTED DRIFTING TO THE L OF CTRLINE. WHEN IT GOT TO ABOUT 20-25 FT L OF CTRLINE; I SAID 'I'VE GOT IT;' AND COMPLETED THE LNDG CLOSER TO THE CTRLINE. INITIALLY; WE HAD SOME HYDROPLANING; BUT WE WERE ABLE TO DEPLOY THE SPOILERS AND REVERSERS. WE WERE NEVER MORE THAN 25 FT L OF CTRLINE DURING THE ENTIRE EVENT. WE STOPPED IN 3/4 LENGTH OF THE RWY. THE REASON I'M WRITING THIS; IS THAT I CAN'T HELP NOTICE THE SIMILARITY BTWN MY EVENT AND THE ACCIDENT. IT WAS A LONG DAY AND VERY LATE AT NIGHT. WITH WX IN THE MIX; IT IS THE PROPER CIRCUMSTANCES FOR PROBS TO OCCUR. FROM THIS IT WAS REINFORCED THAT WE MUST ALWAYS BE ON GUARD.