Joint USAF/NOAA Report of Solar and Geophysical Activity 20 Apr 2008
Product: Report of Solar-Geophysical Activity
Issued: 2008 Apr 20 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 111 Issued at 2200Z on 20 Apr 2008
IA. Analysis of Solar Active Regions and Activity from 19/2100Z to 20/2100Z: Solar activity was very low. Region 991 (S10E15) decayed to a spotless plage.
IB. Solar Activity Forecast: Solar activity is expected to remain very low.
IIA. Geophysical Activity Summary 19/2100Z to 20/2100Z: The geomagnetic field was quiet to unsettled.
IIB. Geophysical Activity Forecast: The geomagnetic field is expected to begin mostly quiet, increasing to unsettled to active on the second and third days of the forecast period as a recurrent coronal hole high speed stream becomes geoeffective. There is a chance geomagnetic field activity will reach minor storm levels at high latitudes.
III. Event Probabilities 21 Apr-23 Apr
- Class M 01/01/01
- Class X 01/01/01
- Proton 01/01/01
- PCAF Green
IV. Penticton 10.7 cm Flux
- Observed 20 Apr 071
- Predicted 21 Apr-23 Apr 075/080/080
- 90 Day Mean 20 Apr 072
V. Geomagnetic A Indices
- Observed Afr/Ap 19 Apr 006/005
- Estimated Afr/Ap 20 Apr 005/005
- Predicted Afr/Ap 21 Apr-23 Apr 005/005-008/008-015/015
VI. Geomagnetic Activity Probabilities 21 Apr-23 Apr
A. Middle Latitudes
- Active 10/20/25
- Minor storm 05/10/15
- Major-severe storm 01/05/10
B. High Latitudes
- Active 10/25/30
- Minor storm 05/10/15
- Major-severe storm 01/05/10