Joint USAF/NOAA Report of Solar and Geophysical Activity 13 Apr 2005
Prepared jointly by the U.S. Dept. of Commerce, NOAA,
Space Environment Center and the U.S. Air Force.
Updated 2005 Apr 13 2210 UTC
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 103 Issued at 2200Z on 13 Apr 2005
IA. Analysis of Solar Active Regions and Activity from 12/2100Z
to 13/2100Z: Solar activity was very low. All of the regions on the
disk were stable and quiet, and the GOES x-ray flux remained below B
level for the entire interval. New Region 753 (N12W06) emerged as
a small, C-type sunspot group.
IB. Solar Activity Forecast: Solar activity is expected to be very
low to low.
IIA. Geophysical Activity Summary 12/2100Z to 13/2100Z:
The geomagnetic field was mostly active with a few minor storm
periods. The enhanced activity is being driven by a high speed
stream from a favorably positioned coronal hole. The greater than 2
MeV electron flux attained high levels during the past 24 hours.
IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be unsettled to active for the next 24 hours (14 April).
The currently enhanced activity level is expected to diminish around
midday on the 14th as the high speed stream moves out of
geoeffective position. Mostly unsettled levels should predominate on
15 April, and quiet to unsettled conditions are expected for 16
April.
III. Event Probabilities 14 Apr-16 Apr
- Class M 05/05/05
- Class X 01/01/01
- Proton 01/01/01
- PCAF green
IV. Penticton 10.7 cm Flux
- Observed 13 Apr 084
- Predicted 14 Apr-16 Apr 085/085/085
- 90 Day Mean 13 Apr 095
V. Geomagnetic A Indices
- Observed Afr/Ap 12 Apr 023/030
- Estimated Afr/Ap 13 Apr 020/027
- Predicted Afr/Ap 14 Apr-16 Apr 015/020-010/015-005/010
VI. Geomagnetic Activity Probabilities 14 Apr-16 Apr
A. Middle Latitudes
- Active 35/15/10
- Minor storm 20/10/05
- Major-severe storm 10/05/05
B. High Latitudes
- Active 25/25/20
- Minor storm 30/20/15
- Major-severe storm 25/15/10
