AT APPRX 2015 CDT, THE PLT CALLED THE SAN ANGELO TOWER AND EXPRESSED CONCERN THAT HIS ACFT MIGHT BE DAMAGED BY HAIL FROM THE WX THAT WAS BLDG IN THE AREA, TOWER PSNL RELAYED AVAILABLE WX INFO & PROVIDED PHONE NUMBERS FOR THE WX BUREAU & A LOCAL FSS. A TORNADO WATCH WAS IN EFFECT FOR NORTHWEST PORTIONS OF THE CONCHO VALLEY, ALSO, THERE WAS A SVR THUNDERSTORM WARNING FOR COKE COUNTY UNTIL 2300 CDT. AT ABOUT THE TIME THE PLT ARRIVED AT THE ARPT, TSTMS WERE BLDG TO THE NORTH. WITNESSES REPORTED THAT THE PLT HURRIEDLY STARTED THE ACFT, TAXIED & TKOF, THEN DEPARTED TO THE EAST. AN AIRLINE AIRCREW ONSVD HVY TSTMS, PRECIPITATION & LIGHTNING EAST OF THE ARPT. A WITNESS EAST OF THE ARPT OBSVD THE ACFT BOUNCING IN TURBL AS IT WENT OVR HIS HOME. HE STATED THAT THE ACFT WAS HEADED TWD WX THAT HAD JUST PASSED. ANOTHER WITNESS SAW THE AIRCRAFT TURN BACK TWD THE ARPT, THEN DESCEND UNTIL IT DISAPPEARED BHND TREES. THE ACFT CRASHED AT NGT IN A LEVEL, WOODED AREA.