MLG ENCOUNTERED SEVERE WIND SHEAR AND DOWNDRAFT ON APCH AT DEN.

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PREFLT AND ENRTE WX RPTS ALL RPTED LOW LEVEL WIND SHEAR ALERTS; CUMULUS AND VIRGA ALL QUADRANTS. WHEN WE BROKE OUT BELOW THE OVCST; VIRGA WAS SEEN AS WELL AS BLOWING DUST DUE N OF DOWNTOWN DENVER; APPROX 4 MI W OF DEN. AT THIS TIME I WAS BUSY TRYING TO AVOID VIRGA LAT; GET CLRNC BELOW THE VIRGA; SLOW THE ACFT WHILE CONFIGURING FOR APCH AND LNDG. WE WERE SWITCHED TO TWR WHILE INTERCEPTING 6-7 MI FINAL. WE WERE CLRED TO LAND AND ADVISED THAT THE ACFT AHEAD OF US HAD EXPERIENCED A 40 KT DECREASE IN AIRSPD AT 3 MI AND ALSO A 10 KT DECREASE AT 20' AGL. DUE TO CONDITIONS ALREADY SEEN; I HAD SET APCH SPD 20 KTS ABOVE REF. I DECIDED TO MAINTAIN CURRENT AIRSPD OF 50 KTS ABOVE REF. CONDITIONS ENCOUNTERED WERE IDENTICAL TO THAT IN OUR SIMULATOR WINDSHEAR TRNING. TO MAINTAIN DSCNT I WAS HAVING TO RETARD THE THROTTLES; BUT DIDN'T COME BACK 1.12 EPR. AS WE FLEW UNDER VIRGA OVER THE APCH COURSE; AIRSPD DROPPED TO REF AND OUR GO AROUND WAS INITIATED. WE COULD FEEL THE AIRPLANE BEING PUSHED DOWN; BUT WERE SOON CLBING AND OUT OF DANGER. WE TURNED DOWNWIND AND LANDED 26R UNEVENTFULLY. IN QUESTIONING MYSELF AS TO WHY THE RWY 17R APCH WAS EVEN ATTEMPTED; I CONCLUDED THAT OTHERS WERE LNDG JUST AHEAD AND COULD DISCERN NO CHANGE IN WX CONDITION BTWN US AND THE ARPT. I HAD NO INDICATION THAT THE ACFT AHEAD HAD GONE AROUND UNTIL WE WERE ENTERING THE SHEAR CONDITIONS AND HEARD TWR ASK IF THAT ACFT WANTED TO CHANGE RWYS AND LAND RWY 26R. HAVING EXPERIENCED SIMULATED WINDSHEAR IN TRNING; I WAS ABLE TO RECOGNIZE THE ENTRY INTO THE SHEAR CONDITIONS AND REACT PROPERLY IN A TIMELY MANNER. IN RETROSPECT; I SHOULD HAVE DISCONTINUED THE APCH WHEN ADVISED OF 40 KT SPD LOSS; BUT CONTINUED ASSUMING THE ACFT AHEAD HAD ENCOUNTERED IT FAR ENOUGH ON APCH AND LANDED. THEREFORE; I SHOULD BE ABLE TO LAND--AN ASSUMPTION I WON'T MAKE AGAIN.