Status Report

Joint USAF/NOAA Report of Solar and Geophysical Activity 29 September 2012

By SpaceRef Editor
September 29, 2012
Filed under , , ,

:Product: Report of Solar-Geophysical Activity
:Issued: 2012 Sep 29 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 273 Issued at 2200Z on 29 Sep 2012
IA. Analysis of Solar Active Regions and Activity from 28/2100Z
to 29/2100Z: Solar activity was at low levels. Numerous weak
C-class events were observed during the past 24 hours, mostly from
Regions 1575 (N07W73) and 1577 (N09W54). New Region 1583 (N13W75)
emerged on the disk as a simple bipolar group. No significant
changes were observed from the remainder of the disk and limb. No
Earth-directed CMEs were observed during the period.
IB. Solar Activity Forecast: Solar activity is expected to be at
low levels with a slight chance for M-class activity all three days
of the forecast period (30 September – 02 October).
IIA. Geophysical Activity Summary 28/2100Z to 29/2100Z:
The geomagnetic field was at quiet levels. ACE satellite
measurements indicated a steady decline in wind speed from about 325
km/s to near 275 km/s while the Bz component of the interplanetary
magnetic field did not vary much beyond +/- 3 nT. At about
29/0100Z, a solar sector boundary crossing from a negative (toward)
to a positive (away) orientation was observed.
IIB. Geophysical Activity Forecast: Geomagnetic field activity is
expected to be at predominately quiet levels through about midday on
day one (30 September). By late on day one, active levels with a
chance for minor to major storm periods are expected due to the
arrival of the Earth-directed CME observed early on 28 September.
On day two (01 October), continued minor to major storm conditions
are expected early in the day, decreasing to mostly quiet to
unsettled levels with a chance for isolated active periods as
effects from the CME wane. Predominately quiet to unsettled
conditions are expected on day three (02 October).
III. Event Probabilities 30 Sep-02 Oct
Class M 10/10/10
Class X 01/01/01
Proton 01/01/01
PCAF green
IV. Penticton 10.7 cm Flux
Observed 29 Sep 136
Predicted 30 Sep-02 Oct 135/130/125
90 Day Mean 29 Sep 125
V. Geomagnetic A Indices
Observed Afr/Ap 28 Sep 002/003
Estimated Afr/Ap 29 Sep 004/004
Predicted Afr/Ap 30 Sep-02 Oct 018/035-018/025-007/008
VI. Geomagnetic Activity Probabilities 30 Sep-02 Oct
A. Middle Latitudes
Active 35/35/10
Minor storm 25/30/05
Major-severe storm 05/10/01
B. High Latitudes
Active 10/10/15
Minor storm 25/20/20
Major-severe storm 60/70/20

SpaceRef staff editor.