ENG STALL RESULTING IN LOSS OF ALT.

Narrative

AT 41000 N 39 DEGS W 62 DEGS I WAS APCHING AN AREA OF WX. I WAS IN OVCST AND I DID CLOUD CONDITIONS; COMPLETE IFR! BOTH RADAR POS DETECTED NO MAJOR CELL RETURNS AT HIGHER ALTS; ONLY SMALLER CELL READOUT WITH ANTENNA TILTED 6-8 DEGS DOWN. HOWEVER; I DIDN'T TRUST THE WX RADAR AND PREVIOUS ACFT HAD DEVIATED AT LOWER ALTS. I DEVIATED APPROX 3 MI TO THE L OF TRACK AROUND WHAT I INTERPRETED TO BE AN AREA OF MORE INTENSE MOISTURE (MORE 'YELLOW' ON COLORED RADAR THAN 'GREEN'). HOWEVER; AS I APCHED TO THE L SIDE OF THIS AREA I NOTICED THE CLOUDS THICKENING AND DARKER. IMMEDIATELY I WAS IN INTENSE TURB AND HVY MOISTURE. I HAD THE IGNITION AND SEAT BELT SIGN ALREADY ON -- NO ENG ANTI-ICE REQUIRED AT SOME MINUS 50 DEGS AT 41000 FT. THE L ENG STARTED RAPID STALLING AND LOSING APPROX 50 PERCENT PWR AND EPR. AIRSPD STARTED DROPPING SLOWLY. I REQUESTED FO TO CALL NEW YORK RADIO FOR DSCNT CLRNC; HOWEVER; ARINC COMS ARE TOO SLOW AND I HAD TO START A SHALLOW DSCNT TO MAINTAIN A SAFE AIRSPD. 1200- 1500 FT WAS LOST UNTIL I FLEW OUT OF MAJOR WX CONDITIONS. I IMMEDIATELY CLBED BACK TO 41000 FT AND WAS ABLE TO RETURN TO RANDOM TRACK. PROBS-SOLUTIONS: 1) NEW YORK RADIO REFUSED PRIOR REQUEST FOR TRACK CHANGES. 2) SOUTHERN RADOM TRACKS SHOULD NOT BE FLOWN IN SUMMERTIME DURING PEAK TSTM ACTIVITIES WHEN A NORTHERN TRACK COULD BE FLOWN -- SOUTHERN TRACKS ARE FLOWN FOR FINANCIAL REASONS; NOT SAFETY. 3) SHOULD HAVE HAD ANTI-ICE ON EVEN IF NOT REQUIRED -- MIGHT HAVE ALSO HELP RELIEVE L ENG STALL (COMPRESSOR STALL). 4) RADAR (ACFT) SYS WERE INADEQUATE TO DETECT HIGH ALT 'DRY MOISTURE' CELL. 5) NO ATC SYS TO HELP WITH CELL DETECTION AND ALLOW ALSO EASY COMS FOR STORM DEVS. ALSO PLT RPTS IN THIS CASE WERE NOT EXISTING.