Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 059 Issued at 2200Z on 28 Feb 2012
IA. Analysis of Solar Active Regions and Activity from 27/2100Z
to 28/2100Z: Solar activity was very low during the past 24 hours.
IB. Solar Activity Forecast: Solar activity is expected to be very
low for the next three days (29 Feb - 02 Mar) with just a slight
chance for an isolated C-class flare.
IIA. Geophysical Activity Summary 27/2100Z to 28/2100Z:
The geomagnetic field ranged from quiet to active levels with a
period of minor storm levels at some observatories during the local
nighttime hours. Quiet conditions prevailed from the beginning of
the period until about 07Z when a substorm interval began and
continued through about 09Z. The planetary activity reached active
levels but several individual stations attained minor storm levels
during the disturbance. Activity promptly returned to predominantly
quiet levels after the substorm and remained quiet for the rest of
the period. The disturbance was preceded by about two hours of
southward interplanetary magnetic field (IMF) seen at the ACE
spacecraft (0510-0702Z, with maximum southward deflection of -11
nT). The IMF was otherwise predominantly northwards during the
interval. ACE data also indicated a solar sector boundary crossing
at about 1534Z. The greater than 10 MeV protons observed by GOES
returned to background levels late on the 27th and remained there
through the end of the period.
IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be quiet for the first two days (29 Feb - 01 Mar). A
slight increase to quiet to unsettled levels is expected on the
third day (02 Mar) due to a small but well positioned coronal hole.