21 January

Solar wind speed, as measured by the ACE spacecraft, exhibited signs of
a weak, positive polarity coronal hole high-speed stream (CH HSS). Wind
speed began the period at approximately 290 km/s, remaining fairly
steady through 20/1700 UTC. They then began a steady increase through
the period and leveled off just after 21/0400 UTC, near 350 km/s. An
isolated bump up to 374 km/s was the peak speed of the period, but
speeds quickly resumed nominal conditions near 330 km/s to finish out
the summary period. IMF total field strength began the period at a
steady 3 nT until just before the end of the UTC day, when it showed an
enhancement of nearly 8 nT. The Bz component varied throughout the day
with a maximum deflection observed of nearly -8 nT, observed at
approximately 21/0910 UTC. The phi angle was predominately oriented in a
positive (away) solar sector with isolated oscillations into a negative
(toward) orientation throughout the period.

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