Joint USAF/NOAA Report of Solar and Geophysical Activity 25 May 2008

Product: Report of Solar-Geophysical Activity
Issued: 2008 May 25 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 146 Issued at 2200Z on 25 May 2008

IA. Analysis of Solar Active Regions and Activity from 24/2100Z to 25/2100Z: Solar activity was at very low levels.

IB. Solar Activity Forecast: Solar activity is expected to remain at very low levels.

IIA. Geophysical Activity Summary 24/2100Z to 25/2100Z: The geomagnetic field was at quiet to unsettled levels. Wind speed measured by the ACE spacecraft began the period at approximately 500 km/s. Since the beginning of the period wind speeds have been declining, and ended the summary period at around 440 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 remain at quiet to unsettled levels, with a slight chance of isolated active conditions at high latitudes for the forecast period (26 to 28 May).

III. Event Probabilities 26 May-28 May

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

IV. Penticton 10.7 cm Flux

• Observed 25 May 068
• Predicted 26 May-28 May 068/068/068
• 90 Day Mean 25 May 071

V. Geomagnetic A Indices

• Observed Afr/Ap 24 May 004/007
• Estimated Afr/Ap 25 May 006/010
• Predicted Afr/Ap 26 May-28 May 005/008-005/008-005/008

VI. Geomagnetic Activity Probabilities 26 May-28 May

A. Middle Latitudes

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

B. High Latitudes

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