MINIMUM FUEL SIT WITH COMMUTER FLC BUT NOT CALLED AS SUCH.

Narrative

ENRTE TO DEST; ARPT WX DROPPED BELOW OUR LNDG MINIMUMS DUE TO FOG. ATC GAVE US HOLDING INSTRUCTIONS AT INTXN ABOUT 30 MI N OF DEST ARPT. FUEL BURN FROM HOLDING POINT TO ALTERNATE ARPT WAS CALCULATED; 45 MINS RESERVE ADDED; AND DECISION TIME WAS SET. AT DECISION TIME ATC GAVE US INITIAL HDG AND RTING TO ALTERNATE ARPT. THIS RTING WAS UNEXPECTEDLY LONG AND ROUND ABOUT; AND WOULD HAVE CUT INTO OUR 45 MIN RESERVE. I ASKED ATC FOR UPDATED RVR AT ORIGINAL DEST. RVR WAS NOW 2000 FT AND ACFT WERE NOW LNDG. I THEN ASKED ATC TO WORK OUT A NEW RTE TO ORIGINAL DEST WITH NO DELAY VECTORS AND THAT IF HE COULD NOT DO THAT WE WOULD HAVE TO GET A MORE DIRECT RTING TO ALTERNATE ARPT REF OUR FUEL. THIS WAS PERCEIVED BY ATC AS A MINIMUM FUEL SIT AND THEY GAVE US PRIORITY HANDLING TO DEST ARPT. WE LANDED AT OUR ORIGINAL DEST WITH 50 MINS WORTH OF FUEL. IN RETROSPECT I SHOULD NOT HAVE WAITED UNTIL I WAS AT MINIMUM FUEL BEFORE PROCEEDING TO MY ALTERNATE. FROM NOW ON I WILL ALWAYS LEAVE MYSELF AN OUT -- AND THEN SOME.