Report of Solar-Geophysical Activity

Issued: 2011 Sep 12 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 255 Issued at 2200Z on 12 Sep 2011

IA.  Analysis of Solar Active Regions and Activity from  11/2100Z
to 12/2100Z:  Solar activity was low during the past 24 hours. Region
1292 (N08E52) produced two C-class flares, the largest a C2 at
12/0329Z. Regions 1293 (N17W11), 1294 (S18E27), and 1295 (N21E72)
were numbered today. Region 1295 produced a C9 at 12/2054Z. The
region is considered an H-type group but is still rotating around
the limb.
IB.  Solar Activity Forecast:  Solar activity is expected to be low
with a chance for isolated M-class events for the next three days
(13-15 September).
IIA.  Geophysical Activity Summary 11/2100Z to 12/2100Z:
The geomagnetic field has been unsettled to active during the past 24
hours due to effects from a favorably positioned coronal hole high
speed stream (CH HSS). The greater than 2 MeV electron flux at
geosynchronous orbit reached high levels during the period.
IIB.  Geophysical Activity Forecast:  The geomagnetic field is
expected to be quiet to unsettled with isolated active periods for
days one and two (13-14 September) due to effects from a CH HSS.
Mostly quiet conditions are expected on day three (15 September) as
CH HSS effects subside.
III.  Event Probabilities 13 Sep-15 Sep
Class M    30/30/30
Class X    01/01/01
Proton     01/01/01
PCAF       Green
IV.  Penticton 10.7 cm Flux
Observed           12 Sep 124
Predicted   13 Sep-15 Sep  120/120/115
90 Day Mean        12 Sep 100
V.  Geomagnetic A Indices
Observed Afr/Ap 11 Sep  008/009
Estimated Afr/Ap 12 Sep  018/028
Predicted Afr/Ap 13 Sep-15 Sep  010/012-008/008-005/005
VI.  Geomagnetic Activity Probabilities 13 Sep-15 Sep
A.  Middle Latitudes
Active                15/15/05
Minor storm           05/01/01
Major-severe storm    01/01/01
B.  High Latitudes
Active                15/15/05
Minor storm           05/01/01
Major-severe storm    01/01/01