Joint USAF/NOAA Report of Solar and Geophysical Activity 24 Apr 2008

Product: Report of Solar-Geophysical Activity
Issued: 2008 Apr 24 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 115 Issued at 2200Z on 24 Apr 2008

IA. Analysis of Solar Active Regions and Activity from 23/2100Z to 24/2100Z: Solar activity was very low.

IB. Solar Activity Forecast: Solar activity is expected to be very low.

IIA. Geophysical Activity Summary 23/2100Z to 24/2100Z: The geomagnetic field was at unsettled to active conditions due to the continued influence of the recurrent coronal hole high speed stream. Solar wind speeds, as measured from the ACE spacecraft, remain around 600 km/s. The greater than 2 MeV electron flux at geosynchronous orbit was at high levels.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be unsettled with isolated active periods for 25 April. Predominantly quiet conditions are expected for 26-27 April.

III. Event Probabilities 25 Apr-27 Apr

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

IV. Penticton 10.7 cm Flux

• Observed 24 Apr 070
• Predicted 25 Apr-27 Apr 070/070/070
• 90 Day Mean 24 Apr 072

V. Geomagnetic A Indices

• Observed Afr/Ap 23 Apr 017/032
• Estimated Afr/Ap 24 Apr 015/022
• Predicted Afr/Ap 25 Apr-27 Apr 010/012-005/008-005/005

VI. Geomagnetic Activity Probabilities 25 Apr-27 Apr

A. Middle Latitudes

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

B. High Latitudes

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