TKOF WHEN ACFT GROSS WT ABOVE RWY WT LIMITATION.

Narrative

AFTER FUELING AND PAX LOADING I DISCOVERED WE WOULD BE OVER 7000 POUNDS ABOVE MAX TKOF WT FOR WIND AND TEMP CONSIDERATIONS. AS PNF IT WAS MY DUTY TO DO THE TKOF AND PERFORMANCE CALCULATIONS. I IMMEDIATELY NOTIFIED THE CAPT OF THE OVERLOADING CONDITION. OUR FLT DISPATCH HAD FAILED TO RECOGNIZE THE WARM TEMP AND WIND CONDITIONS AND RELEASED OUR FLT AT A WT ABOVE MAX TKOF WT FOR THE CURRENT CONDITIONS. THE CAPT ACKNOWLEDGED OUR WT CONDITION AFTER HE ALSO REVIEWED THE TKOF DATA/PERFORMANCE CHART. HE ELECTED TO DEPART THE GATE ON TIME AND SAID WE WOULD WAIT FOR LESS TAILWIND OR COOLER TEMPS BEFORE COMMENCING TKOF. WE ASKED THE TWR NUMEROUS TIMES DURING TAXI OUT AND WHILE HOLDING SHORT OF THE DEP RWY WHAT THE CURRENT WIND/TEMP CONDITIONS WERE. BECAUSE OF TERRAIN AND RWY SLOPE; WE NEEDED TO TKOF TO THE S. HOWEVER; WINDS WERE PREVAILING CONSTANTLY OUT OF THE N. CONSEQUENTLY; DICTATING A TKOF WITH A TAILWIND! AT ONE POINT WINDS WERE RPTED TO BE 340 DEG AT GUSTING 17 KTS. A RAIN SHOWER PASSED BY WHILE WE WERE HOLDING SHORT OF RWY AT A HIGHER IDLE PWR SETTING TO BURN OFF WT. WITH DIFFERENT TEMP AND WIND CONDITIONS USED IN CALCULATIONS I ADVISED THE CAPT AT LEAST 4 TIMES WE WOULD STILL BE ABOVE MAX TKOF WT. AFTER THE RAIN SHOWER HAD PASSED AND SITTING APPROX 45 MINS AT HIGH IDLE PWR AND TWR ADVISED US THE TEMP WAS NOT 6 DEG COOLER. THIS PUT US RIGHT AT MAX TKOF WT WITH A 0 WIND COMPONENT. AT ONE POINT WE TOLD THE TWR WE NEEDED A 0 WIND COMPONENT TO LEGALLY TKOF. WHILE NOTICING A LIMP WINDSOCK THE CAPT TOLD THE TWR WE WERE READY FOR TKOF; HOWEVER; THE TWR ADVISED WIND OF 330 AT 6 KTS GIVING US A 5 KT TAILWIND COMPONENT! WE HAD APPROX A 1000 POUND WT PENALTY PER 1 KT TAILWIND COMPONENT PUTTING US STILL ALMOST 5000 POUNDS OVER WT. WE PROCEEDED TO SAFELY TKOF. THE CAPT KNEW WE WERE OVER WT BUT I FELT PUT COMPANY AND PAX CONNECTION REASONS ABOVE SAFETY. AS FO I POLITELY SAID SEVERAL TIMES WE WOULD STILL BE OVER WT UNLESS A 0 WIND CONDITION OCCURRED. THE FE NEVER EXPRESSED HIS CONCERN OR FEELINGS FOR OUR WT CONDITIONS. I WISHED HE WOULD HAVE BACKED ME UP MORE. IT WAS ALSO THE LAST LEG OF A 3 DAY TRIP.