The Safety Board's full report on this investigation is provided as Aviation Accident Report number AAR-86/05. To obtain a copy of this report, or to view the executive summary online, please see the Web site at http://www.ntsb.gov/publictn/publictn.htm PSBL SCATTERED THUNDERSTORMS (TSTMS) WERE FORCAST & DRG ARRIVAL, SVRL CELLS WERE DEVELOPING IN THE AREA. DELTA FLT 191 WAS VECTORED ARND A LARGE CELL, THEN WAS SEQUENCED BHND OTHER ACFT & CLRD FOR AN ILS RWY 17L APCH. THE FLT CREW & SVRL PRECEEDING CREWS SAW LIGHTNING IN A CELL NORTH OF THE ARPT, BUT CONTD W/O RPRTG IT. ON THE APCH, FLT 191 ENCOUNTERED A MICROBURST WHILE PASSING UNDER THE CELL. INITIALLY, THE 1ST OFFICER, WHO WAS FLYING THE ACFT, RETARDED THE THROTTLES IN A HEADWIND. THE ACFT THEN ENCOUNTERED APRX 73 KTS OF WINDSHEAR, UP/DWNDFTS, VORTEX FLOW & A TAILWIND. GO-AROUND PWR WAS APPLIED, BUT THE ACFT STRUCK THE GND APRX 6300' NORTH OF RWY 17L, HIT A CAR & 2 WATER TANKS, BROKE APART & BURNED. INV REVEALED THAT BTN 1752 & 1800 CDT, THE TSTM CELL GREW FM VIP LVL 1 TO VIP LVL 4. A CENTER WX SVC UNIT METEOROLOGIST WAS ON DUTY, BUT NOT AT THE RADAR PSN AT THAT TIME & DIDN'T OBSV THE CELL GROWTH. CAPT'S DECISION TO CONT APCH DIDN'T COMPLYWITH DELTA'S WX AVOIDANCE PROC; THERE WAS A LACK OF SPECIFIC GUIDANCE & TRAINING FOR AVOIDING/ESCAPING LOW ALT WNDSHEAR.