Joint USAF/NOAA Report of Solar and Geophysical Activity 27 May 2008

Product: Report of Solar-Geophysical Activity
Issued: 2008 May 27 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 148 Issued at 2200Z on 27 May 2008

IA. Analysis of Solar Active Regions and Activity from 26/2100Z to 27/2100Z: Solar activity was at very low levels. The visible disk was spotless.

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

IIA. Geophysical Activity Summary 26/2100Z to 27/2100Z: The geomagnetic field was at quiet levels. 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 be at mostly quiet levels for day one (28 May). Activity is expected to increase to quiet to unsettled levels with a slight chance for isolated active periods on days two and three (29 and 30 May). The increase in activity is forecast due to a recurrent coronal high speed stream that is expected to rotate into a geoeffective position.

III. Event Probabilities 28 May-30 May

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

IV. Penticton 10.7 cm Flux

• Observed 27 May 068
• Predicted 28 May-30 May 068/068/068
• 90 Day Mean 27 May 071

V. Geomagnetic A Indices

• Observed Afr/Ap 26 May 003/004
• Estimated Afr/Ap 27 May 005/005
• Predicted Afr/Ap 28 May-30 May 005/005-008/010-008/010

VI. Geomagnetic Activity Probabilities 28 May-30 May

A. Middle Latitudes

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

B. High Latitudes

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