Joint USAF/NOAA Report of Solar and Geophysical Activity 24 May 2007
Product: Report of Solar-Geophysical Activity
Issued: 2007 May 24 2200 UTC
Prepared jointly by the U.S. Dept. of Commerce, NOAA,
Space Environment Center and the U.S. Air Force.
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 144 Issued at 2200Z on 24 May 2007
IA. Analysis of Solar Active Regions and Activity from 23/2100Z to 24/2100Z: Solar activity was very low. Region 956 (S01W74) has decayed into a plage region without spots.
IB. Solar Activity Forecast: Solar activity is expected to be very low.
IIA. Geophysical Activity Summary 23/2100Z to 24/2100Z: The geomagnetic field ranged from unsettled to major storming. Extended periods of southward Bz starting on 23 May, combined with rising solar wind speeds, accounted for the most disturbed periods. Solar wind speed increased to approximately 650 km/s during the summary period due to a recurrent coronal hole rotating into a geoeffective position. The greater then 2 MeV electron flux at geosynchronous orbit reached high levels today.
IIB. Geophysical Activity Forecast: The geomagnetic field is expected to range from unsettled to major storming over the next three days. Elevated solar wind speeds due to the geoeffective coronal hole and transient material from the CME’s on 22 and 23 May should produce storm periods on 25 – 26 May. Expect mostly unsettled to active conditions on 27 May.
III. Event Probabilities 25 May-27 May
- Class M 01/01/01
- Class X 01/01/01
- Proton 01/01/01
- PCAF green
IV. Penticton 10.7 cm Flux
- Observed 24 May 070
- Predicted 25 May-27 May 070/070/065
- 90 Day Mean 24 May 073
V. Geomagnetic A Indices
- Observed Afr/Ap 23 May 028/042
- Estimated Afr/Ap 24 May 018/020
- Predicted Afr/Ap 25 May-27 May 020/025-020/025-015/020
VI. Geomagnetic Activity Probabilities 25 May-27 May
A. Middle Latitudes
- Active 40/40/30
- Minor storm 25/25/15
- Major-severe storm 10/10/05
B. High Latitudes
- Active 40/40/40
- Minor storm 25/25/25
- Major-severe storm 15/15/10
