Joint USAF/NOAA Report of Solar and Geophysical Activity 25 Oct 2007

Product: Report of Solar-Geophysical Activity
Issued: 2007 Oct 25 2232 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 298 Issued at 2200Z on 25 Oct 2007

IA. Analysis of Solar Active Regions and Activity from 24/2100Z to 25/2100Z: Solar activity was at very low levels. The visible solar disk remains spotless.

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

IIA. Geophysical Activity Summary 24/2100Z to 25/2100Z: The geomagnetic field ranged from quiet to minor storm conditions, major storm levels were observed at high latitudes. The ACE spacecraft observed a co-rotating interaction region at 25/1040Z. Solar wind speed has increased to approximately 700 km/s, and Bz has ranged between +/-17 nT, indicating the onset of a coronal hole high speed stream. The greater than 2 MeV electron flux at geosynchronous orbit reached high levels today.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at unsettled to active conditions due to the coronal hole high speed stream throughout the forecast period (26 – 28 October). Minor storm levels at middle latitudes and major storm conditions at high latitudes are possible on day one of the forecast period.

III. Event Probabilities 26 Oct-28 Oct

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

IV. Penticton 10.7 cm Flux

• Observed 25 Oct 067
• Predicted 26 Oct-28 Oct 067/067/067
• 90 Day Mean 25 Oct 068

V. Geomagnetic A Indices

• Observed Afr/Ap 24 Oct 002/003
• Estimated Afr/Ap 25 Oct 015/015
• Predicted Afr/Ap 26 Oct-28 Oct 020/020-010/012-008/010

VI. Geomagnetic Activity Probabilities 26 Oct-28 Oct

A. Middle Latitudes

• Active 35/20/15
• Minor storm 20/15/10
• Major-severe storm 10/05/01

B. High Latitudes

• Active 35/25/20
• Minor storm 25/20/15
• Major-severe storm 15/05/01