Report of Solar-Geophysical Activity

Issued: 2011 Sep 15 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 258 Issued at 2200Z on 15 Sep 2011

IA.  Analysis of Solar Active Regions and Activity from  14/2100Z
to 15/2100Z:  Solar activity was low. Nine C-class flares were
observed during the period. The largest was a C4/Sf at 15/0029Z from
Region 1297 (S18W64). Region 1295 (N22E30) showed growth in its
trailing spots.
IB.  Solar Activity Forecast:  Solar activity is expected to be low
with a chance for isolated M-class flares during the period (16-18
September).
IIA.  Geophysical Activity Summary 14/2100Z to 15/2100Z:
The geomagnetic field was at predominantly quiet levels. The greater
than 2 MeV electron flux at geosynchronous orbit was at high levels
throughout the period.
IIB.  Geophysical Activity Forecast:  The geomagnetic field is
expected to be at predominantly quiet levels on day one (16
September). Unsettled to active levels are possible late on day one,
due to the expected arrival of the full halo CME observed at
14/0000Z. Activity is expected to be at unsettled to active levels,
with isolated minor storm levels at high latitudes on day two (17
September) as the CME continues. Activity is expected to decrease to
quiet to active levels on day three (18 September).
III.  Event Probabilities 16 Sep-18 Sep
Class M    35/35/35
Class X    01/01/01
Proton     01/01/01
PCAF       green
IV.  Penticton 10.7 cm Flux
Observed           15 Sep 141
Predicted   16 Sep-18 Sep  140/140/135
90 Day Mean        15 Sep 101
V.  Geomagnetic A Indices
Observed Afr/Ap 14 Sep  005/004
Estimated Afr/Ap 15 Sep  004/004
Predicted Afr/Ap 16 Sep-18 Sep  010/010-018/020-010/015
VI.  Geomagnetic Activity Probabilities 16 Sep-18 Sep
A.  Middle Latitudes
Active                25/25/25
Minor storm           10/15/10
Major-severe storm    01/05/01
B.  High Latitudes
Active                30/30/30
Minor storm           15/20/15
Major-severe storm    05/05/01