25 February

ACE data continued to exhibit signs consistent with a waning
positive-polarity coronal hole high-speed stream (CH HSS). Wind speed
began the period as high as 527 km/s, but then gradually decreased to
end the period just over 410 km/s. IMF Bt (total field intensity)
remained fairly consistent between 1 nT and 4 nT the entire period,
while the Bz component of the IMF was variable through the end of the UT
day. Just after the beginning of the new UT day, Bz went north and
remained there until just after 0800 UT, when it went south again,
holding steady near – 1 nT to end the period. IMF Phi data indicated a
positive-polarity (Away) solar sector during the first part of the
period, but began oscillating between sectors after 2000 UTC until the
end of the period.

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