FLC OF A BRITISH HAWKER 125-800 TEMPORARILY LOST COMS WITH APCH CTL WHILE TURNING TO AVOID WX NEAR THE FAF.

Narrative

WE WERE ON RADAR VECTORS AND DEVIATING AROUND LEVEL 4 TSTM ACTIVITY; APPROX 4 MI FROM FAF FROM RWY 24L AT SUS. ON MAKING OUR TURN TOWARD FAF; THE LINE OF TSTMS THAT HAD BEEN TO THE S OF THE ARPT MOVED IN OVER THE FAF AND TSTMS THAT HAD BEEN W OF ARPT HAD NOW MOVED ON TO THE ARPT. OUR ONLY OPTION WAS TO TURN R AND HEAD E OR SE. ON FINAL VECTORS OUR CONTACT WITH APCH CTLR WAS BROKEN AND WE LOST COM WITH THEM ON 126.7. SO WE MADE THE R TURN ON OUR OWN AND RE-ESTABLISHED RADIO CONTACT ON ANOTHER FREQ. THIS R TURN PUT US CLOSE TO THE ARR CORRIDOR AT STL. REDUCED SEPARATION FROM ATC STANDPOINT BUT NOT CLOSE ENOUGH TO THE OTHER ACFT TO TRIGGER A TA OR RA FROM EITHER ACFT. BEING FAMILIAR WITH THE AREA WE WERE IN VMC MONITORING BOTH OUR WX RADAR AND TCASII. AFTER RE-ESTABLISHING COM WITH ATC THEY GAVE US A CLB TO 4000 FT AND VECTORED OVER THE TOP OF STL. WE THEN DIVERTED TO ALN AND LANDED SAFELY; CALLING ATC ON LANDLINE PER THEIR REQUEST. THE TURN WE MADE WOULD HAVE BEEN NECESSARY EVEN IF WE HAD NOT LOST COM (RADIO) PROBS; IN ORDER TO AVOID THIS SEVERE WX. WE ARE NOT SURE IF THE RADIO PROB WAS THE ACFT OR ATC RADIOS.