We obtained three consecutive HST spectroscopic observations of a single superoutburst of the dwarf nova VW Hydri .
The spectra cover the beginning , middle , and end of the superoutburst .
All of the spectra are dominated by strong absorption lines due to CIII ( 1175 Å ) , Lyman alpha ( 1216 Å ) , NIV ( 1238 Å , 1242 Å ) , SII ( 1260-65 Å ) , SIII ( 1300 Å ) , CII ( 1335 Å ) , SIV ( 1394 Å , 1402 Å ) and CIV ( 1548 Å , 1550 Å ) .
We discuss the evolution of the far UV energy distribution and line structure during the superoutburst .
We note the absence of any P Cygni line structure in the STIS spectra .
Using state of the art accretion disk models by Wade and Hubeny , we have determined accretion rates for all three spectra , for two white dwarf masses , 0.55 M _ { \sun } and 0.8 M - { \sun } .
For both white dwarf masses the accretion rate during superoutburst decreased by a factor of two from early to late in the superoutburst .
The average accretion rate during superoutburst is 3 - 6 \times 10 ^ { -9 } M _ { \sun } /yr depending on the white dwarf mass .