Joint USAF/NOAA Report of Solar and Geophysical Activity 21 Oct 2007

Product: Report of Solar-Geophysical Activity
Issued: 2007 Oct 21 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 294 Issued at 2200Z on 21 Oct 2007

IA. Analysis of Solar Active Regions and Activity from 20/2100Z to 21/2100Z: Solar activity was very low. No flares were observed during the past 24 hours, and the visible disk remained spotless.

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

IIA. Geophysical Activity Summary 20/2100Z to 21/2100Z: The geomagnetic field was quiet. Real-time solar wind observations from ACE show solar wind velocity gradually declined during the past 24 hours to approximately 455 km/s at forecast issue time. 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 quiet on 22 October. Quiet to unsettled levels are expected on 23 October. Expect conditions to range from quiet to active levels on 24 October, with a chance for minor storm periods, as a recurrent coronal hole becomes geoeffective.

III. Event Probabilities 22 Oct-24 Oct

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

IV. Penticton 10.7 cm Flux

• Observed 21 Oct 067
• Predicted 22 Oct-24 Oct 067/067/067
• 90 Day Mean 21 Oct 068

V. Geomagnetic A Indices

• Observed Afr/Ap 20 Oct 008/012
• Estimated Afr/Ap 21 Oct 003/005
• Predicted Afr/Ap 22 Oct-24 Oct 005/005-005/008-010/015

VI. Geomagnetic Activity Probabilities 22 Oct-24 Oct

A. Middle Latitudes

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

B. High Latitudes

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