Solar activity was low. Region 1520 (S16W58) produced todays largest event, a C7/Sf with maximum at 16/2003Z. Additional low level C-class events were observed during the period with regions 1520, 1519 (S17W81), 1521 (S22W71), and 1522 (N11W76) all contributing. All of the spotted regions on the disk were generally unchanged or slowly declining. There were some preliminary observations indicating a new region (yet to be numbered) rotating onto the disk in the southern hemisphere. No Earth-directed CMEs were observed during the past 24 hours. (NOTE: todays F10.7 flux is based on the morning 1800Z reading because the 2000Z observation was flare enhanced).

Solar activity is expected to be low, but with a continued chance for an isolated M-class event. Region 1520 is the most likely source. A decline in activity and background levels is expected on the third day as Regions 1519, 1520, and 1521 cross west limb.

The geomagnetic field ranged from unsettled to major storm levels (estimated Kp between 3 and 6). The period began with a continuation of storm level activity in response to the 12 July CME. Activity gradually subsided with mostly active conditions (estimated Kp of 4) from 0600-1500Z and unsettled levels for the remainder of the period. There were some lingering major storm intervals at high latitudes in the 0600-1800Z timeframe. Solar wind observations from ACE showed a continuation of the CME passage: initial values of the Z-component of the interplanetary magnetic field were around -15 nT and slowly weakened through the day, finally turning northwards at 1424Z. A second, much weaker phase of southward Bz began at 1755Z with maximum value around -4.5 nT. Solar wind velocity declined also, with initial values around 510 km/s and end-of-day values around 440 km/s.

Geomagnetic activity is expected to be unsettled with a chance for active periods during the next 24 hours (17 July). In addition, there is a chance for isolated minor to major storm periods at high latitudes during the earlier part of 17 July. Solar wind driving of the magnetosphere is expected to continue to decrease in intensity throughout the day and predominantly quiet levels are expected for the second and third days (18-19 July).

  Observed       16 Jul 138
  Predicted   17 Jul-19 Jul  135/120/105
  90 Day Mean        16 Jul 129

  Observed Afr/Ap 15 Jul  039/086
  Estimated     Afr/Ap 16 Jul  021/032
  Predicted    Afr/Ap 17 Jul-19 Jul  007/012-006/005-007/005