Joint USAF/NOAA Report of Solar and Geophysical Activity 11 Aug 2004
Prepared jointly by the U.S. Dept. of Commerce, NOAA,
Space Environment Center and the U.S. Air Force.
Updated 2004 Aug 11 2200 UTC
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 224 Issued at 2200Z on 11 Aug 2004
IA. Analysis of Solar Active Regions and Activity from 10/2100Z
to 11/2100Z: Solar activity was low. Today’s activity consisted of
numerous C-class flares, predominantly from Region 656 (S13E03). The
largest event of the day was a C7/Sf from 656 at 1141 UTC. Region
656 continues to grow and is nearly 1000 millionths in area. The
group continues to have a magnetic delta classification. A slow,
faint CME was seen in LASCO off the south limb yesterday, beginning
at about 10/1854 UTC in C2 imagery. The CME was associated with
surge activity and a subsequent EIT wave that was observed just
north of 656 and east of central meridian.
IB. Solar Activity Forecast: Solar activity is expected to be low
to moderate. C-flares should continue and there is a good chance for
an isolated M-class event during the next three days. There is also
a slight chance for a major flare event from 656. Background levels
are expected to increase tomorrow with the return of old Region 652
(N07, Carrington = 347).
IIA. Geophysical Activity Summary 10/2100Z to 11/2100Z:
The geomagnetic field ranged from quiet to active levels. Solar wind
data show the continuing influence of a high-speed coronal hole wind
stream. The greater than 2 MeV electron fluxes reached high levels
during the past 24 hours.
IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be generally unsettled with a chance for isolated active
periods for the next two days (12-13 August). Conditions are
expected to be unsettled to active on the 3rd day (14 August) with
the arrival of weak transient flow from yesterday’s CME.
III. Event Probabilities 12 Aug-14 Aug
- Class M 55/55/55
- Class X 10/10/10
- Proton 10/10/10
- PCAF green
IV. Penticton 10.7 cm Flux
- Observed 11 Aug 131
- Predicted 12 Aug-14 Aug 140/145/150
- 90 Day Mean 11 Aug 107
V. Geomagnetic A Indices
- Observed Afr/Ap 10 Aug 012/014
- Estimated Afr/Ap 11 Aug 012/013
- Predicted Afr/Ap 12 Aug-14 Aug 010/010-010/010-015/012
VI. Geomagnetic Activity Probabilities 12 Aug-14 Aug
A. Middle Latitudes
- Active 30/30/35
- Minor storm 15/15/20
- Major-severe storm 05/05/05
B. High Latitudes
- Active 35/35/40
- Minor storm 15/15/20
- Major-severe storm 05/05/05