Joint USAF/NOAA Report of Solar and Geophysical Activity 17 May 2008

Product: Report of Solar-Geophysical Activity
Issued: 2008 May 17 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 138 Issued at 2200Z on 17 May 2008

IA. Analysis of Solar Active Regions and Activity from 16/2100Z to 17/2100Z: Solar activity was very low.

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

IIA. Geophysical Activity Summary 16/2100Z to 17/2100Z: The geomagnetic field was quiet.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be quiet on the first day of the forecast period (18 May), becoming unsettled to active on day two as a recurrent coronal hole high speed stream becomes geoeffective. Conditions on day three will continue to be unsettled to active, with a chance for minor storms at high latitudes.

III. Event Probabilities 18 May-20 May

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

IV. Penticton 10.7 cm Flux

• Observed 17 May 071
• Predicted 18 May-20 May 072/072/072
• 90 Day Mean 17 May 071

V. Geomagnetic A Indices

• Observed Afr/Ap 16 May 003/004
• Estimated Afr/Ap 17 May 005/005
• Predicted Afr/Ap 18 May-20 May 005/005-010/012-015/030

VI. Geomagnetic Activity Probabilities 18 May-20 May

A. Middle Latitudes

• Active 10/20/30
• Minor storm 05/10/15
• Major-severe storm 01/01/05

B. High Latitudes

• Active 10/25/45
• Minor storm 05/15/25
• Major-severe storm 01/01/10