B757 FLC DEVIATING DUE TO WX; INITIATE EVASIVE MANEUVER DUE TO OPPOSITE DIRECTION B757 AT SAME ALT WHILE UNDER ZFW CTL.

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WITH CLRNC; WE WERE DEVIATING BTWN STORMS 50 MI S OF ABI AT FL370. WE WERE INSTRUCTED TO CLB TO FL410 AND STARTED OUR CLB. WE THEN TURNED OFF OF OUR EASTERLY HDG TOWARD THE SE. SHORTLY THEREAFTER; WE RECEIVED A TA ON THE TCASII. AT THE SAME TIME CTR TOLD US TO TURN L IMMEDIATELY. THE TA TURNED TO AN RA BUT WE WERE ALREADY RESPONDING. WE ACQUIRED THE TFC VISUALLY AND PASSED THE TFC ABOUT 400 FT ABOVE AND APPROX 1/2 MI TO THE N. WE CONTINUED OUR CLB TO FL410. THE CTLR SAID HE DIDN'T KNOW WE WERE TURNING SE BUT WE HAD CLRNC TO DEVIATE AS NECESSARY. SUPPLEMENTAL INFO FROM ACN 473329: CONFLICT WAS 11:30 O'CLOCK POS AT APPROX 8 MI AT SAME ALT OF FL390. THE CTLR STATED HE DID NOT KNOW WE WERE DEVIATING S. WE RESTATED WE HAD REQUESTED AND RECEIVED A CLRNC TO DEVIATE S FOR WX. ATC DID NOT RESPOND. SUPPLEMENTAL INFO FROM ACN 473242: A LINE OF WX HAD IMPACTED THE AREA FROM 50 MI W OF SAN ANGELO; TX; EXTENDING TO THE NE SEVERAL HUNDRED MI. I HAD RECEIVED A BRIEFING THAT INDICATED ALL ACFT WERE STAYING S AND W OF SJT BEFORE RETURNING TO COURSE. A PIREP INDICATED TOPS AT FL350 TO FL370. THIS INFO LED ME TO BELIEVE THAT ACFT AT OR ABOVE FL370 MAY NOT DEVIATE AS MUCH AS PREVIOUSLY EXPECTED AND ACFT AT FL390 MAY NOT DEVIATE AT ALL. I ASKED THE PLT OF ACFT 1 IF HE WAS PLANNING TO DEVIATE S OR CONTINUE ON HIS PRESENT HDG. HIS RESPONSE WAS THAT 'PRESENT HDG IS GOOD FOR ACFT 1.' I DID NOT RECEIVE RTE INFO ON ACFT 2 BECAUSE MY SECTOR TEAM HAD NOT INFORMED ME OF IT. THE PREVIOUS INFO INDICATED TO ME THAT BOTH ACFT WERE LATERALLY SEPARATED BY 20 MI AND WOULD CONTINUE TO MAINTAIN LATERAL SEPARATION AS WELL AS VERT SEPARATION. THE FLT OF ACFT 1 WAS CONVERGING WITH ANOTHER FLT AT FL370. I ASKED THE PLT OF ACFT 1 IF HE COULD ACCEPT FL410. I ALSO DETERMINED THAT LATERAL SEPARATION WOULD CONTINUE TO EXIST FROM ACFT 2. EACH ACFT WAS ON OPPOSITE SIDES OF THE LINE OF WX AS WELL. DURING A TIME LAPSE OF 1 MIN OR LESS; THE PLT OF ACFT 1 HAD MADE A TURN FOR WX DEV OF APPROX 30 DEGS S WITHOUT ADVISING ATC. THE PLT OF ACFT 2 HAD MADE A TURN TO APPARENTLY RETURN TO COURSE OF APPROX 60 DEGS WITHOUT ADVISING ATC. I SCANNED THE SECTOR FOR PROBS. I FINISHED MY SCAN BACK AT ACFT 1 TO REF HIS CLB PERFORMANCE. I THEN DISCOVERED THE TURNS AND PROBABLE LOSS OF SEPARATION. I CLRED THE PLT OF ACFT 1 TO TURN L IMMEDIATELY. I THEN CLRED THE PLT OF ACFT 2 TO TURN L IMMEDIATELY FOLLOWED BY A TFC CALL TO THE PLT OF ACFT 1. CONFLICT ALERT ACTIVATED AND CONTINUED UNTIL SEPARATION WAS REGAINED. CONFLICT ALERT WAS NOT AN ADEQUATE TOOL IN THIS SCENARIO BECAUSE THE PREDICTION OF LOSS OF SEPARATION DID NOT OCCUR WITH ANY TIME LEFT TO CORRECT THE PROB. THIS WAS DUE TO LARGE HDG CHANGES AND HIGH AIRSPDS. AS THE PRIMARY CTLR INVOLVED; I HAD WORKED 7 1/2 HRS OF HVY AND COMPLEX TFC AT MAX WORKLOAD THROUGHOUT THE DAY AND I WAS FATIGUED. I HAD ONLY BEEN WORKING THE SECTOR FOR A VERY SHORT PERIOD OF TIME IN THAT SESSION AND DID NOT HAVE A FEEL FOR WHAT THE GENERAL FLOW OF TFC WAS AT THE TIME. ALTHOUGH HE PROBABLY HAD A PREVIOUS CLRNC TO DO SO; ANY HDG CHANGE OF MORE THAN 20 DEGS SHOULD ALWAYS BE RELAYED TO ATC IN MY OPINION. A CTLR NEVER KNOWS WHEN A RETURN TO COURSE WILL HAPPEN BECAUSE EVERY PLT IS DIFFERENT AND EVERY FLT ENCOUNTERS DIFFERENT WX PROBS FROM MIN TO MIN. A RETURN TO COURSE THAT EMPLOYS A DRASTIC HDG CHANGE SHOULD ALWAYS BE PRECLUDED WITH AN ADVISORY TO ATC. CTLRS SHOULD ALWAYS BE ON THE LOOKOUT FOR THE UNUSUAL AND UNEXPECTED AND PROVIDE VERY CONSERVATIVE SEPARATION TECHNIQUES WHEN WORKING AROUND SUCH AN UNPREDICTABLE ENVIRONMENT. SUPPLEMENTAL INFO FROM ACN 473510: AREA OF CONCERN INVOLVED COORD BTWN 5 DIFFERENT SECTORS. ALL 5 SECTORS HAD DEVIATING ACFT AND MOST CONFLICTS WERE OCCURRING ON OUTER BOUNDARIES OF SECTORS WHICH MADE IT MORE DIFFICULT TO DEVISE ALTERNATE ROUTINGS. THE INK SECTOR WHERE ERROR OCCURRED IS A 200 MI SECTOR MAKING IT DIFFICULT TO EXPAND OUT TO SEE SITS THAT ARE DEVELOPING ALONG THE BOUNDARIES.