Viewing archive of Thursday, 29 September 2011
Solar activity report
Any mentioned solar flare in this report has a scaling factor applied by the Space Weather Prediction Center (SWPC). Because of the SWPC scaling factor, solar flares are reported as 42% smaller than for the science quality data. The scaling factor has been removed from our archived solar flare data to reflect the true physical units.
Report of Solar-Geophysical Activity 2011 Sep 29 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 272 Issued at 2200Z on 29 Sep 2011IA. Analysis of Solar Active Regions and Activity from 28-2100Z to 29-2100Z Solar activity has been low for the past 24 hours.
Region 1305 (N13E16) has grown in aerial coverage and is now
considered a Cso-type spot group with a beta-gamma magnetic
configuration. The region produced a C1 event at 29/1023Z. Region
1302 (N13W16) produced a long duration C2/Sf at 29/1247Z. A Type II
Radio Sweep with an estimated speed of 608 km/s was associated with
this event. It is difficult to see in STEREO COR2 imagery but does
appear to be Earth directed with an estimated plane-of-sky speed of
628 km/s. Further analysis will be done as LASCO imagery becomes
available.
IB. Solar Activity Forecast
Solar activity is expected to be low
for the next three days (30 September - 02 October) with a chance
for isolated M-class and X-class events mainly from Region 1302.
IIA. Geophysical Activity Summary 28-2100Z to 29-2100Z
The geomagnetic field was mostly unsettled with isolated minor to
major storm levels observed between 29/0000-0600Z due to
substorming. Solar wind speeds jumped slightly to 600 km/s, in
conjunction with an increase in temperature and density around
29/0030Z. Bt reached +13 nT and Bz dipped south with a maximum
deviation of -10 nT.
IIB. Geophysical Activity Forecast
The geomagnetic field is
expected to be quiet to unsettled with a chance for isolated active
periods early on day one (30 September) due to residual effects from
the CME. Quiet to unsettled conditions are expected on day two (01
October) due to the arrival of a recurrent coronal hole high speed
stream. Quiet to unsettled conditions are expected on day three (02
October).
III. Event Probabilities 30 Sep to 02 Oct
| Class M | 60% | 60% | 60% |
| Class X | 30% | 30% | 30% |
| Proton | 15% | 15% | 15% |
| PCAF | green | ||
IV. Penticton 10.7 cm Flux
Observed 29 Sep 137 Predicted 30 Sep-02 Oct 140/140/140 90 Day Mean 29 Sep 110
V. Geomagnetic A Indices
Observed Afr/Ap 28 Sep 013/024 Estimated Afr/Ap 29 Sep 015/015 Predicted Afr/Ap 30 Sep-02 Oct 010/012-008/010-005/005
VI. Geomagnetic Activity Probabilities 30 Sep to 02 Oct
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 20% | 10% | 05% |
| Minor storm | 05% | 01% | 01% |
| Major-severe storm | 01% | 01% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 25% | 10% | 05% |
| Minor storm | 05% | 05% | 01% |
| Major-severe storm | 01% | 01% | 01% |
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