Joint USAF/NOAA Report of Solar and Geophysical Activity 04 Oct 2007

Product: Report of Solar-Geophysical Activity
Issued: 2007 Oct 04 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 277 Issued at 2200Z on 04 Oct 2007

IA. Analysis of Solar Active Regions and Activity from 03/2100Z to 04/2100Z: Solar activity was very low. The visible disk remained spotless.

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

IIA. Geophysical Activity Summary 03/2100Z to 04/2100Z: The geomagnetic field ranged from quiet to active levels due to a recurrent coronal hole high speed steam. Earlier on 03 October, minor to major storm levels were observed at high latitudes between 0600-1500Z due to this high speed stream. Real-time solar wind speed at ACE reached a maximum of approximately 600 km/s at 04/0102Z and has gradually decreased to approximately 515 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, with isolated unsettled periods early on day one (05 October). Quiet conditions are expected for the remainder of the forecast period.

III. Event Probabilities 05 Oct-07 Oct

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

IV. Penticton 10.7 cm Flux

• Observed 04 Oct 067
• Predicted 05 Oct-07 Oct 067/067/067
• 90 Day Mean 04 Oct 069

V. Geomagnetic A Indices

• Observed Afr/Ap 03 Oct 009/018
• Estimated Afr/Ap 04 Oct 007/010
• Predicted Afr/Ap 05 Oct-07 Oct 005/005-005/005-005/005

VI. Geomagnetic Activity Probabilities 05 Oct-07 Oct

A. Middle Latitudes

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

B. High Latitudes

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