Joint USAF/NOAA Report of Solar and Geophysical Activity 18 May 2007

Product: Report of Solar-Geophysical Activity
Issued: 2007 May 18 2200 UTC
Prepared jointly by the U.S. Dept. of Commerce, NOAA,
Space Environment Center and the U.S. Air Force.

Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 138 Issued at 2200Z on 18 May 2007

IA. Analysis of Solar Active Regions and Activity from 17/2100Z to 18/2100Z: Solar activity was very low. Region 956 (N03E07) continues to display a beta-gamma-delta magnetic configuration, but has not produced any flares during the past 24 hours.

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

IIA. Geophysical Activity Summary 17/2100Z to 18/2100Z: The geomagnetic field has been quiet to active. Solar wind speed increased to approximately 600 km/s during the past 12 hours, indicating the onset of a coronal hole high speed stream.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be unsettled to active with a chance for minor storm periods on 19 May due to the coronal hole high speed stream. Expect quiet to unsettled conditions on 20 – 21 May.

III. Event Probabilities 19 May-21 May

• Class M 15/15/15
• Class X 01/01/01
• Proton 01/01/01
• PCAF green

IV. Penticton 10.7 cm Flux

• Observed 18 May 076
• Predicted 19 May-21 May 075/075/075
• 90 Day Mean 18 May 074

V. Geomagnetic A Indices

• Observed Afr/Ap 17 May 004/006
• Estimated Afr/Ap 18 May 010/015
• Predicted Afr/Ap 19 May-21 May 010/020-008/010-005/005

VI. Geomagnetic Activity Probabilities 19 May-21 May

A. Middle Latitudes

• Active 25/20/15
• Minor storm 10/05/01
• Major-severe storm 05/01/01

B. High Latitudes

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