CONVECTIVE WX REQUIRES ACR CREW TO USE EMER AUTH TO REFUSE ARTCC VECTORS. A TFC SEPARATION PROB RESULTED THAT WAS HANDLED BY ARTCC.

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WE WERE CRUISING AT FL370 APPROX 100 NM NW OF SLT VOR IN COMS WITH ZOB. WE WERE DEVIATING AROUND NUMEROUS LEVEL 4 AND 5 TSTMS AND HAD BEEN DOING SO FOR APPROX THE LAST 700-800 NM. THE TOPS OF MANY OF THE STORMS EXCEEDED OUR OWN ALT; MAKING OVERFLT IMPOSSIBLE. AS WE PREPARED TO PASS BTWN TWO SUCH CLOSELY-SPACED BUILD-UPS ON A SOUTHEASTERLY HEADING; WE OBSERVED THAT THE GAP WE WERE AIMING FOR BEGAN TO CLOSE RAPIDLY AS THE 2 CELLS MERGED. WE ASSUMED A NORTHERLY HEADING (THE ONLY COURSE OF ACTION) PLACING A LARGE TSTM TO OUR R. SHORTLY THEREAFTER; ZOB CTLR REQUESTED THAT WE PERFORM A R 360 DEG TURN TO AVOID A POTENTIAL TFC CONFLICT. THIS WOULD HAVE CAUSED US TO PENETRATE THE BUILD-UP TO OUR R; WHICH APPEARED TO BE VERY ACTIVE AND HAD ALL THE INDICATIONS OF SEVERE AND/OR EXTREME TURB. BELIEVING THAT A R TURN WOULD PLACE OUR ACFT; PAX; AND CREW IN EXTREME JEOPARDY; WE ADVISED THE CTLR THAT WE WERE DEVIATING FURTHER; (WE USED CAPT'S EMER AUTH UNDER 91.3); L TO REMAIN CLR OF THE BUILD-UP; WHICH THE CTLR DID NOT APPROVE. THE CTLR REQUESTED ANOTHER ACFT; WHICH APPARENTLY WAS ON A CONVERGING COURSE; TO DSND. THE ACFT APPEARED ON OUR TCASII BRIEFLY AS IT DID SO; AND WE ACQUIRED IT VISUALLY IMMEDIATELY THEREAFTER. AT NO TIME WAS THERE A HAZARD OF COLLISION; AND AN RA (TCASII) WAS NOT GENERATED. WE THEN MANEUVERED CLR OF THE BUILD-UP AND THE FLT CONTINUED TO EWR WITHOUT FURTHER INCIDENT. THE CAPT ON THE GND SPOKE WITH THE ATC FACILITY SUPVR VIA LANDLINE UPON ARR IN EWR. THE SUPVR STATED THAT THE CTR SEPARATION CRITERIA HAD BEEN SLIGHTLY COMPROMISED WITH THE ABOVE ACFT'S NEVER GETTING CLOSER THAN 4.1 NM APART. HE FURTHER STATED THAT HE UNDERSTOOD OUR POS AND THAT HE BELIEVED OUR COURSE OF ACTION TO BE APPROPRIATE UNDER THE CIRCUMSTANCES. THIS CREW FIRMLY BELIEVE THAT THE CTLR NOR THE FLT DECK CREW DID ANYTHING WRONG. EACH PARTY WAS CONFRONTED WITH A SET OF PROB CONFLICTING WITH ONE ANOTHER. THE PROFESSIONALISM OF EVERYBODY INVOLVED CONTRIBUTED TO THE SAFE RESOLUTION OF THE SIT. THE CTLR DOES NOT SEE WHAT WE SEE. THERE IS NOT EVEN AN ACCURATE RADAR RETURN WX PICTURE OVERLAID. THIS IS ONE OF THOSE SIT WHEN A RIGID (AND BLIND) SYS DOES NOT MAKE ROOM FOR A VERY DYNAMIC CHANGING WX PROB.