Joint USAF/NOAA Report of Solar and Geophysical Activity 12 Apr 2005
Prepared jointly by the U.S. Dept. of Commerce, NOAA,
Space Environment Center and the U.S. Air Force.
Updated 2005 Apr 12 2210 UTC
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 102 Issued at 2200Z on 12 Apr 2005
IA. Analysis of Solar Active Regions and Activity from 11/2100Z
to 12/2100Z: Solar activity was low due to a C2/Sf flare at 1721 UTC
from newly assigned Region 752 (N00E76). There were additional
B-class events during the past 24 hours and all of these were from
752 as well. At this time Region 752 is a small, D-type sunspot
region.
IB. Solar Activity Forecast: Solar activity is expected to be low
for the next three days (13-15 April).
IIA. Geophysical Activity Summary 11/2100Z to 12/2100Z:
The geomagnetic field ranged from quiet to major storm levels.
Conditions were at mostly active to minor storm levels during the
past 24 hours with a major storm interval at high latitudes from
0000-0300 UTC. The enhanced activity is being driven by a favorably
positioned coronal hole.
IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be mostly active for the next 36 hours (13 April to 14
April 1200 UTC) due to persistent coronal hole effects. Conditions
should begin to decline partway through the 14th and should be quiet
to unsettled by the 3rd day (15th).
III. Event Probabilities 13 Apr-15 Apr
- Class M 05/05/05
- Class X 01/01/01
- Proton 01/01/01
- PCAF green
IV. Penticton 10.7 cm Flux
- Observed 12 Apr 085
- Predicted 13 Apr-15 Apr 085/085/085
- 90 Day Mean 12 Apr 096
V. Geomagnetic A Indices
- Observed Afr/Ap 11 Apr 006/010
- Estimated Afr/Ap 12 Apr 020/025
- Predicted Afr/Ap 13 Apr-15 Apr 020/025-012/018-007/010
VI. Geomagnetic Activity Probabilities 13 Apr-15 Apr
A. Middle Latitudes
- Active 40/35/20
- Minor storm 25/20/10
- Major-severe storm 10/10/05
B. High Latitudes
- Active 40/35/30
- Minor storm 35/25/15
- Major-severe storm 15/15/10
