Report of Solar-Geophysical Activity

Issued: 2012 Sep 03 2200 UTC
Prepared jointly by the U.S. Dept. of Commerce, NOAA,
Space Weather Prediction Center and the U.S. Air Force.

Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 247 Issued at 2200Z on 03 Sep 2012

IA.  Analysis of Solar Active Regions and Activity from  02/2100Z
to 03/2100Z:  Solar activity was low. Regions 1560 (N03W33 -
Eki/beta-gamma-delta) and 1564 (S16E26 - Esi/beta-gamma) each
produced occasional C-class flares. Region 1560 increased in
magnetic complexity to a beta-gamma-delta configuration with a delta
evident in its interior spots. Region 1564 was in a gradual growth
phase during the period and increased in magnetic complexity to a
beta-gamma configuration. Region 1553 (S21W82 - Dso/beta) produced
occasional optical subflares as it neared the west limb. New Region
1566 (N24E76 - Hax/alpha) was numbered. There were no Earth-directed
coronal mass ejections (CME) observed during the period.
IB.  Solar Activity Forecast:  Solar activity is expected to be low
through the period (04 - 06 September) with a chance for isolated M-
class flares.
IIA.  Geophysical Activity Summary 02/2100Z to 03/2100Z:
Geomagnetic field activity ranged from unsettled to major storm
levels with a brief period of severe storm levels detected at high
latitudes. An interplanetary shock passed the ACE spacecraft at
03/1123Z indicating the arrival of the Halo CME observed on 31
August. This was followed by a geomagnetic sudden impulse at
03/1214Z (28 nT, Boulder USGS Magnetometer). Field activity
increased to major storm levels during 03/1200 - 1500Z following the
sudden impulse, then decreased to active levels for the rest of the
period, with minor storm periods detected at high latitudes. The greater than 10 MeV proton event at geosynchronous orbit
that began at 01/1335Z, reached a maximum of 60 pfu at 02/0850Z, and
was in progress as the period ended.
IIB.  Geophysical Activity Forecast:  Geomagnetic field activity is
expected to be at unsettled to active levels on day 1 (04 September)
with a chance for minor storm levels as CME effects wind down. Quiet
to unsettled conditions are expected during days 2 - 3 (05 - 06
September) with a chance for active levels due to arrival of
Earth-directed CMEs observed on 02 September along with a
co-rotating interaction region ahead of a coronal hole high-speed
stream (CH HSS). The CH HSS is expected to commence on day 3. The
greater than 10 MeV proton event at geosynchronous orbit is expected
to end on day 1.
III.  Event Probabilities 04 Sep-06 Sep
Class M    30/30/30
Class X    05/05/05
Proton     50/30/10
PCAF       green
IV.  Penticton 10.7 cm Flux
Observed           03 Sep 142
Predicted   04 Sep-06 Sep  140/140/135
90 Day Mean        03 Sep 124
V.  Geomagnetic A Indices
Observed Afr/Ap 02 Sep  014/015
Estimated Afr/Ap 03 Sep  021/028
Predicted Afr/Ap 04 Sep-06 Sep  014/015-010/012-009/010
VI.  Geomagnetic Activity Probabilities 04 Sep-06 Sep
A.  Middle Latitudes
Active                30/20/20
Minor storm           20/05/05
Major-severe storm    05/01/01
B.  High Latitudes
Active                15/15/15
Minor storm           15/20/30
Major-severe storm    10/20/25