Solar wind measurements at the ACE spacecraft indicated steady solar
wind speeds with a gradual increase at 04/0300 UTC from about 325 km/s
to near 375 km/s. The total IMF Bt was steady at 4-5 nT through about
04/0000 UTC when a gradual increase was observed, peaking at 13 nT at
about 04/0800 UTC. Bt ended the period at 10 nT. The Bz component
followed the same pattern with little variability off neutral through
04/0600 UTC, becoming mostly northward to +6 to +10 nT after that. Phi
angle was in a steady positive (away) orientation throughout the period.