Joint USAF/NOAA Report of Solar and Geophysical Activity 28 Apr 2008

Product: Report of Solar-Geophysical Activity
Issued: 2008 Apr 28 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 119 Issued at 2200Z on 28 Apr 2008

IA. Analysis of Solar Active Regions and Activity from 27/2100Z to 28/2100Z: Solar activity was very low. No flares were observed during the past 24 hours.

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

IIA. Geophysical Activity Summary 27/2100Z to 28/2100Z: The geomagnetic field was 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 quiet to unsettled with isolated active periods for the next three days. An increase is expected late on day one (29 April) or early on day two (30 April) in response to a glancing blow from the CME that was observed on 26 April.

III. Event Probabilities 29 Apr-01 May

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

IV. Penticton 10.7 cm Flux

• Observed 28 Apr 069
• Predicted 29 Apr-01 May 070/070/070
• 90 Day Mean 28 Apr 072

V. Geomagnetic A Indices

• Observed Afr/Ap 27 Apr 007/010
• Estimated Afr/Ap 28 Apr 010/010
• Predicted Afr/Ap 29 Apr-01 May 008/008-010/012-010/015

VI. Geomagnetic Activity Probabilities 29 Apr-01 May

A. Middle Latitudes

• Active 20/30/30
• Minor storm 05/05/05
• Major-severe storm 01/05/05

B. High Latitudes

• Active 40/45/50
• Minor storm 10/15/15
• Major-severe storm 05/05/05