AFTER TAKEOFF, THE FLT PROGRESSED NORMALLY, EXCEPT ONE ARTCC CONTROLLER HAD DIFFICULTY COMMUNICATING WITH THE PLT DURING THE EARLY PART OF THE FLT. AFTER CRUISING AT 11,000 FT FOR APRX 2 HRS, THE PLT OBTAINED UPDATED WX INFO & REQUESTED CLEARANCE TO DESCEND TO 9000 FT TO AVOID BUILD-UPS. HE WAS CLEARED TO DEVIATE & DESCEND AT HIS DISCRETION & HE ACKNOWLEDGED. SHORTLY THEREAFTER, RADAR & RADIO CONTACT WERE LOST. AN IN-FLT BREAK-UP OCCURRED & THE WRECKAGE WAS SCATTERED OVER A WIDE AREA. THE HORIZONTAL STABILIZERS WERE FOUND APRX 2-1/2 MI FROM THE MAIN WRECKAGE. THERE WAS EVIDENCE THAT THEY HAD FAILED IN A SLIGHT UP & REARWARD DIRECTION. NO PRE-ACCIDENT FAILURES WERE FOUND. WX DATA SHOWED THAT THE ACFT LIKELY PENETRATED THE EDGE OF A STRONG (VIP LEVEL 3) THUNDERSTORM WITH SEVERE TURBULENCE, RAIN & UP/DOWNDRAFTS. A CHECK OF THE PLT'S BLOOD SHOWED A SMALL AMOUNT OF ALCOHOL (0.05%); HOWEVER, THE AMOUNT DUE TO POSSIBLE PUTREFACTION OR CONTAMINATION WAS NOT DETERMINED.