Joint USAF/NOAA Report of Solar and Geophysical Activity 30 Apr 2007

Product: Report of Solar-Geophysical Activity
Issued: 2007 Apr 30 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 120 Issued at 2200Z on 30 Apr 2007

IA. Analysis of Solar Active Regions and Activity from 29/2100Z to 30/2100Z: Solar activity was very low. There was slight decay in penumbral area on the trailing edge of Region 953 (S10E09), however, the spot group is maintaining a beta gamma delta magnetic classification. New Region 954 (S05E29) was numbered today.

IB. Solar Activity Forecast: Solar activity is expected to be very low to low with a chance for an M-flare from Region 953.

IIA. Geophysical Activity Summary 29/2100Z to 30/2100Z: The geomagnetic field was at quiet to minor storm conditions. Activity was due to the continued influence of a coronal hole high speed stream. Solar wind speed at ACE has decreased from approximately 680 km/s to 570 km/s. The greater than 2 MeV electron flux at geosynchronous orbit reached high levels again today.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be quiet to unsettled for the forecast period (01 – 03 May).

III. Event Probabilities 01 May-03 May

• Class M 15/15/15
• Class X 05/05/05
• Proton 01/01/01
• PCAF Gree

n

IV. Penticton 10.7 cm Flux

• Observed 30 Apr 087
• Predicted 01 May-03 May 085/085/085
• 90 Day Mean 30 Apr 074

V. Geomagnetic A Indices

• Observed Afr/Ap 29 Apr 016/023
• Estimated Afr/Ap 30 Apr 012/018
• Predicted Afr/Ap 01 May-03 May 008/008-005/005-005/005

VI. Geomagnetic Activity Probabilities 01 May-03 May

A. Middle Latitudes

• Active 20/15/15
• Minor storm 10/05/05
• Major-severe storm 01/01/01

B. High Latitudes

• Active 25/20/15
• Minor storm 10/10/05
• Major-severe storm 05/01/01