Joint USAF/NOAA Report of Solar and Geophysical Activity 28 Apr 2007

Product: Report of Solar-Geophysical Activity
Issued: 2007 Apr 28 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 118 Issued at 2200Z on 28 Apr 2007

IA. Analysis of Solar Active Regions and Activity from 27/2100Z to 28/2100Z: Solar activity was very low. Region 953 (S10E36) has not changed much in area and has only managed to produce several B-class flares.

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

IIA. Geophysical Activity Summary 27/2100Z to 28/2100Z: The geomagnetic field was at unsettled to minor storm conditions as a recurrent coronal hole high speed stream continues to be geoeffective. Solar wind speeds at ACE are enhanced around 640 km/s. The greater than 2 MeV electron flux at geosynchronous orbit reached high levels today.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at unsettled to minor storm conditions on 29 April. Mostly unsettled conditions are expected on 30 April. Conditions are expected to decrease to quiet to unsettled levels by 01 May.

III. Event Probabilities 29 Apr-01 May

• Class M 20/20/20
• Class X 05/05/05
• Proton 01/01/01
• PCAF Green

IV. Penticton 10.7 cm Flux

• Observed 28 Apr 085
• Predicted 29 Apr-01 May 085/085/085
• 90 Day Mean 28 Apr 074

V. Geomagnetic A Indices

• Observed Afr/Ap 27 Apr 010/016
• Estimated Afr/Ap 28 Apr 020/030
• Predicted Afr/Ap 29 Apr-01 May 015/015-010/010-005/008

VI. Geomagnetic Activity Probabilities 29 Apr-01 May

A. Middle Latitudes

• Active 30/25/15
• Minor storm 15/10/05
• Major-severe storm 05/05/01

B. High Latitudes

• Active 30/30/25
• Minor storm 25/15/10
• Major-severe storm 15/05/05