GRB 050421***A***, Swift-BAT refined analysis S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team): Using the data set from T-299 to T+303 sec from the recent telemetry downlink, we report further analysis of BAT GRB 050421***A*** (trigger #115135) (NAME, et al., GCN Circ. xxxx). The BAT ground-calculated position is RA, Dec = 307.381, 73.674 deg which is RA(J2000) = 20h 29m 31.5s Dec(J2000) = +73d 40' 24.9" with an uncertainty of 2.8 arcmin, (radius, sys+stat, 90% containment). The partial coding was 87%. [Description about the mask-weighted light curve] T90 (15-350 keV) is 8.4 +- 3.4 sec (estimated error including systematics). The time-averaged spectrum from T+0.0 to T+8.7 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.67 +- 0.43. The fluence in the 15-150 keV band is 9.3 +- 2.7 x 10^-08 erg/cm2. The 1-sec peak photon flux measured from T+0.40 sec in the 15-150 keV band is 0.4 +- 0.1 ph/cm2/sec. All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/115135/BA/