Joint USAF/NOAA Report of Solar and Geophysical Activity 23 May 2008

Product: Report of Solar-Geophysical Activity
Issued: 2008 May 23 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 144 Issued at 2200Z on 23 May 2008

IA. Analysis of Solar Active Regions and Activity from 22/2100Z to 23/2100Z: Solar activity was very low. The visible disk remains spotless.

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

IIA. Geophysical Activity Summary 22/2100Z to 23/2100Z: The geomagnetic field was quiet to unsettled during the past 24 hours. Solar wind speed at ACE remains elevated between 450-520 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 predominantly quiet to unsettled for the next three days (24-26 May). Isolated active periods remain possible on days 1 and 2 (24-25 May).

III. Event Probabilities 24 May-26 May

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

IV. Penticton 10.7 cm Flux

• Observed 23 May 068
• Predicted 24 May-26 May 068/068/068
• 90 Day Mean 23 May 071

V. Geomagnetic A Indices

• Observed Afr/Ap 22 May 007/009
• Estimated Afr/Ap 23 May 006/010
• Predicted Afr/Ap 24 May-26 May 008/010-008/010-005/008

VI. Geomagnetic Activity Probabilities 24 May-26 May

A. Middle Latitudes

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

B. High Latitudes

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