ACR B757 EXECUTED MISSED APCH DUE TO TURB ASSOCIATED WITH TSTM AND DIVERTED TO ALTERNATE ARPT. ARRIVING AT ALTERNATE ARPT ANOTHER ACR FLT EXECUTED A MISSED APCH BECAUSE OF TURB SO; FLC AGAIN DIVERTED; BUT WITHOUT COORD WITH THE DISPATCHER. ACFT LANDED AT ARPT WITH MINIMUM FUEL AND; BECAUSE THE ARPT WAS NOT AUTH FOR B757 LNDGS; CAPT SHOULD HAVE DECLARED AN EMER.

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FLT X EXECUTED A MISSED APCH AT SLC DUE TO TURB ASSOCIATED WITH TSTM ACTIVITY. FLT WENT INTO HOLDING AND CONTACTED ME TO DISCUSS SIT AND LOOK AT ALTERNATIVES. TSTM ACTIVITY JUST MOVING INTO SLC. BASED ON WX AT SLC; FUEL REMAINING IN HOLDING; 12700 LBS; IT WAS DECIDED TO DIVERT TO BOI; THE ALTERNATE. AT TIME OF DIVERSION; THE LATEST BOI WX WAS 290 DEGS AT 12 KTS; 10 NM VISIBILITY CLR 26/12 A2989 RMK A02 SLP020. BOI WX FROM 2 PREVIOUS HRS HAD BEEN SAME 10 SM VISIBILITY CLR. RADAR INDICATED TSTM ACTIVITY BTWN X AND BOI BUT TSTM ACTIVITY WAS E OF BOI. UPON ARR BOI; FLT X HAD AN ACR B FLT EXECUTE A MISSED APCH DUE TO TURB AND WIND SHEAR ASSOCIATED WITH TSTMS AT BOI. FLT X DID NOT MAKE AN APCH INTO BOI AND INSTEAD DIVERTED TO TWF WITHOUT CONTACTING ME. I DISCOVERED FLT X WAS DIVERTING TO TWF AFTER CONTACTING OPS PERSONNEL IN BOI AND LEARNING THAT X FLT WAS HDG TO TWF. FLT X HAD DROPPED OFF OF MY GRAPHICAL FLT FOLLOWING SCREEN. WHEN I REACQUIRED FLT X ON GFF; THE INFO STRIP INDICATED THAT IT WAS CLRED TO TWF AND WAS CURRENTLY AT ALT 7000 FT. I ATTEMPTED TO CONTACT FLT X VIA THE COMPANY VHF RADIO BUT WAS NOT SUCCESSFUL. I NOTIFIED TWF OF THE IMPENDING ARR OF X. ACARS COMS WITH FLT ALSO FAILED TO WORK EITHER FROM MY INITIATION OR FROM THE CREW DOWNLINK TO ME. I WAS NOT ABLE TO TALK TO THE CAPT UNTIL FLT HAD BLOCKED INTO TWF AND THE CAPT CALLED ME ON THE TELEPHONE. 2 PROBS WITH THIS FLT WERE LACK OF UPDATED WX RADAR INFO AND LACK OF COMS WITH THE FLT. OUR ACR HAS AVAILABLE TO ITS DISPATCHER A 5 MIN RADAR COMPOSITE AND A 15 MIN RADAR COMPOSITE. THE 5 MIN RADAR WAS OVER 1 HR 30 MINS OLD AND THE 15 MIN RADAR 45 MINS OLD. OUR ACR IS WORKING ON A FIX FOR BOTH OF THOSE PROBS. THE COM PROB WAS PROBABLY A COMBINATION OF FLT X LOW ALT; WX ACTIVITY; AND GEOGRAPHICAL AREA. THE CAPT DID NOT DECLARE AN EMER; HOWEVER HE SHOULD HAVE SINCE TWF IS NOT AUTH FOR B757 EQUIP. THE CAPT DID ACT PRUDENTLY AS FLT X LANDED WITH 4300 LBS OF FUEL REMAINING.