ACR WDB ALT DEV EXCURSION FROM CLRNC ALT IN TSTM ACTIVITY.

Narrative

WE TOOK OFF FROM PHL ON RWY 9L. AFTER TKOF DEP CTL CLRED US TO 10000 FT AND DIRECT TO MXE VOR. WHEN ENRTE TO MXE WE SAW TSTMS DEAD AHEAD AND TO THE R OF OUR FLT PATH. NOTIFIED DEP WE NEEDED A L TURN TO CIRCUMNAV LARGE BUILDUP. RADAR PICTURE SHOWED INTENSE RETURN (CONTOUR). DEP SAID UNABLE L TURN DUE TO RESTR AREA. WE THEN REQUESTED A CLB AS VISUALLY WE FELT WE COULD TOP THE LARGEST RETURN AT ABOUT 13000 FT. DEP CTL WAS UNABLE HIGHER AND SWITCHED US TO NEW YORK CENTER. WE REQUESTED IMMEDIATE CLB AND/OR L TURN TO AVOID THE TSTM CELL. AFTER SEVERAL CALLS TO NEW YORK CENTER AND NO RESPONSE WE SWITCHED BACK TO PHL DEP AND AGAIN REQUESTED; WITH URGENCY; A L TURN. PHL SAID UNABLE BUT GAVE US R TURN TO AN E HDG. AT THAT TIME; TO AVOID FLYING INTO THE CELL; I TURNED R. WE PENETRATED THE CELL AND ENTERED STRONG UPDRAFTS WHICH CAUSED US TO GAIN APPROX 500 FT. I IMMEDIATELY INITIATED CORRECTIVE ACTION AND DSNDED BACK TO 10000 FT AND EXITED THE CELL ON THE E HDG. WE THEN HELD APPROX 15 MINS ON PTW 190/10 AS INSTRUCTED BY PHL DEP UNTIL CENTER AIRSPACE WAS AVAILABLE AND CONTINUED FLT TO DEST. PROBLEM AROSE WHEN; DUE TO TFC; RESTR AIRSPACE; AND TSTMS WE WERE UNABLE TO MANEUVER TO AVOID HAZARDOUS WX. PROBLEM WAS WORSENED WHEN NEW YORK CENTER FAILED TO GIVE US A CLRNC TO AVOID THE WX. BY THE TIME WE GOT BACK TO PHL DEP IT WAS TOO LATE TO AVOID FLYING INTO THE FRINGES OF THE BUILDUP WHICH CAUSED THE ALT DEV.