Joint USAF/NOAA Report of Solar and Geophysical Activity 27 Apr 2008
Product: Report of Solar-Geophysical Activity
Issued: 2008 Apr 27 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 118 Issued at 2200Z on 27 Apr 2008
IA. Analysis of Solar Active Regions and Activity from 26/2100Z to 27/2100Z: Solar activity was very low. No flares were observed during the past 24 hours and the solar disk is void of spots. Yesterday’s CME (associated with the B3 x-ray flare at 26/1408) could be seen to be transiting the STEREO-A and B Heliospheric Imager I (HI1) fields of view.
IB. Solar Activity Forecast: Solar activity is expected to be very low.
IIA. Geophysical Activity Summary 26/2100Z to 27/2100Z: The geomagnetic field was predominantly quiet to unsettled. The greater than 2 MeV electron flux at geosynchronous orbit reached high levels during the past 24 hours.
IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be mostly quiet for the first day (28 April) and most of the second day (29 April). An increase is possible late on the second day or early on the third day (30 April) due to an anticipated glancing blow from the CME that was observed on 26 April. Activity is expected to increase to predominantly unsettled levels at that time with a chance for isolated active periods.
III. Event Probabilities 28 Apr-30 Apr
- Class M 01/01/01
- Class X 01/01/01
- Proton 01/01/01
- PCAF Green
IV. Penticton 10.7 cm Flux
- Observed 27 Apr 068
- Predicted 28 Apr-30 Apr 068/068/068
- 90 Day Mean 27 Apr 072
V. Geomagnetic A Indices
- Observed Afr/Ap 26 Apr 005/010
- Estimated Afr/Ap 27 Apr 007/008
- Predicted Afr/Ap 28 Apr-30 Apr 005/005-007/008-010/012
VI. Geomagnetic Activity Probabilities 28 Apr-30 Apr
A. Middle Latitudes
- Active 10/20/25
- Minor storm 05/10/15
- Major-severe storm 01/01/05
B. High Latitudes
- Active 10/25/30
- Minor storm 05/10/20
- Major-severe storm 01/05/05
