6th December

The solar wind environment at the ACE satellite indicated fairly nominal
conditions through about 06/0320 UTC. Wind speeds averaged about 450
km/s, IMF total field (Bt) ranged from 4-7 nT while the Bz component did
not vary much beyond +/- 5 nT. The phi angle was highly variable between
a negative (towards) and a positive (away) sector. After 05/0320 UTC,
phi rotated to a steady negative sector, wind speeds gradually increased
to near 475 km/s, Bt sharply increased to near 20 nT and Bz varied
between +16 nT to -6 nT. EPAM low energy particles also showed a gradual
increase indicating the possible arrival of a co-rotating interaction
region in advance of an anticipated negative polarity coronal hole high
speed stream (CH HSS).

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