MD-83
Flight Crew Air Transport Pilot (ATP)
Workload; Troubleshooting; Confusion; Distraction
Deviation - Speed All Types; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Weight And Balance
Flight Crew FLC Overrode Automation; Flight Crew Took Evasive Action
Aircraft; Procedure
Normally used Runway XXR was closed but we were able to pull up departure numbers for XXL the shorter south side runway. We also had a slight tailwind departing in the southwest direction. Based on our closeout we were legal for departure but runway limited and somewhat near our balanced field limit. To add a margin of safety I elected to also do a packs off takeoff. The takeoff roll seemed long but we reached rotate with approximate 2;000 FT remaining and broke ground with approximate 1;000 feet remaining. Then during climb with the flaps and slats retracted we had to roll the autothrottle air speed up to 260 KIAS before the alpha speed warning extinguished in the thrust window of the FMA. 260 KIAS was 13 KTS above the expected 247 KIAS clean min maneuver speed set from our departure plan TPS.  After cruise altitude level off (lowed than flight plan because of gross weight concerns) I called Dispatch and ordered an arrival off load audit. We flew the arrival into our filed destination using a higher than shown gross weight speeds to add a margin of safety not knowing exactly heavy we were.  Possible overweight takeoff and possible overweight landing at ZZZ.
[This report contains no additional information.]
A MD-83 takeoff roll was excessive and during climb with flaps and slats retracted a clean climb speed of 263 KTS was maintained to extinguish the ALPA SPD warning. Excessive takeoff weight suspected.