Joint USAF/NOAA Report of Solar and Geophysical Activity 20 May 2007

Product: Report of Solar-Geophysical Activity
Issued: 2007 May 20 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 140 Issued at 2200Z on 20 May 2007

IA. Analysis of Solar Active Regions and Activity from 19/2100Z to 20/2100Z: Solar activity was very low. Region 956 (N04W18) produced a long-duration B6 flare at 20/0556Z, but no evidence of an associated CME has been observed.

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

IIA. Geophysical Activity Summary 19/2100Z to 20/2100Z: The geomagnetic field was quiet to unsettled. Solar wind speed remains slightly elevated at approximately 540 km/s due to a coronal hole high speed stream.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be quiet to unsettled for the next three days (21 – 23 May).

III. Event Probabilities 21 May-23 May

• Class M 10/10/10
• Class X 01/01/01
• Proton 01/01/01
• PCAF green

IV. Penticton 10.7 cm Flux

• Observed 20 May 074
• Predicted 21 May-23 May 075/075/075
• 90 Day Mean 20 May 074

V. Geomagnetic A Indices

• Observed Afr/Ap 19 May 010/012
• Estimated Afr/Ap 20 May 006/010
• Predicted Afr/Ap 21 May-23 May 008/012-005/010-005/005

VI. Geomagnetic Activity Probabilities 21 May-23 May

A. Middle Latitudes

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

B. High Latitudes

• Active 30/25/15
• Minor storm 15/15/05
• Major-severe storm 05/01/01