GPWS ALERT SOUNDED AT 4800 FT DURING A NIGHT OP VISUAL APCH FOR A DSNDING A320 9 NM S OF RWY 1R AT LAS; NV.

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FLT AB WAS CLRED FOR A VISUAL APCH TO RWY 1R AT LAS IN GOOD VMC. I WAS THE PF. WE WERE VECTORED TO THE FINAL APCH COURSE AND CLRED FOR A VISUAL APCH WITH THE ARPT ENVIRONMENT CLRLY IN SIGHT; APPROX 15 MI AWAY. I HAD SELECTED THE VISUAL RWY 1R APCH FROM THE FMC DATABASE AND I MANEUVERED THE ACFT TO THE EXTENDED CTRLINE AS DEPICTED ON THE PFD USING MANAGED NAV; AUTOPLT ENGAGED. THE VERT PATH INDICATOR ON THE PFD SHOWED THE AIRPLANE HIGH ON THE PROJECTED VERT PATH BY ABOUT 2000 FT. I CONFIGURED TO FLAPS 1 DEG; FOLLOWED A BIT LATER BY GEAR DOWN; SINCE I DETERMINED THAT WE WERE HIGH AND; MOREOVER; THE AIRPLANE NEEDED TO SLOW. THE RWY ENVIRONMENT WAS CLRLY IN SIGHT. THE APCH CTLR CASUALLY MENTIONED THAT HE OBSERVED '...A LOW TERRAIN ALERT.' NOW; WITH THE APCH PATH STILL HIGH AT ABOUT 1100 FT AND THE RWY ENVIRONMENT CLRLY INSIGHT AND CONSIDERING THAT I HAD CONDUCTED THIS APCH PATH NUMEROUS TIMES IN THE PAST UNDER IDENTICAL CONDITIONS; I WAS PERPLEXED. I ARRESTED THE DSCNT. I BEGAN A CLB. I DISCONNECTED THE AUTOPLT AND THE FLT DIRECTORS AND CALLED FOR THE INBOUND COURSE IN FCU. THE GPWS SOUNDED '...TERRAIN; TER...' AND WAS SILENT. BEFORE I COULD MOVE TO ADVANCE THRUST AND FULL BACK STICK; THE WARNING ENDED. THE RWY ENVIRONMENT TO RWY 1R WAS CLRLY IN SIGHT TO BOTH PLTS. I RESUMED A NORMAL DSCNT AND CONFIGN TO A NORMAL LNDG IN LAS. CONTRIBUTING FACTORS MAY HAVE BEEN THAT IN SPITE OF MY EXPERIENCE WITH THE TERMINAL AND LNDG IN LAS; I HAD NOT FLOWN FOR 2 MONTHS PREVIOUS TO THIS FLT. MOREOVER; I SHOULD HAVE BRIEFED THE PNF FOR TERRAIN AWARENESS. THE APCH CTLR MIGHT HAVE BEEN SOMEWHAT MORE FORCEFUL WITH HIS ADVISORY; ALTHOUGH I WAS ULTIMATELY RESPONSIBLE FOR MY TERRAIN CLRNC. IN THE FUTURE; I PLAN TO USE THE RNAV APCH PROC FROM THE DATABASE AS A MEANS TO ENSURE ADEQUATE TERRAIN CLRNC AND APCH MONITORING. THE AREA IN QUESTION IS VERY DARK AND INDISTINCT TO TERRAIN JUDGEMENT UNTIL THE LAST FEW MI. ALSO; HAD THE ACFT BEEN EQUIPPED WITH EGPWS; WE WOULD HAVE BEEN AWARE OF SOME OBSTACLE MUCH SOONER. EGPWS WAS MADE FOR JUST SUCH AN EVENT.