Joint USAF/NOAA Report of Solar and Geophysical Activity 29 Sep 2007

Product: Report of Solar-Geophysical Activity
Issued: 2007 Sep 29 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 272 Issued at 2200Z on 29 Sep 2007

IA. Analysis of Solar Active Regions and Activity from 28/2100Z to 29/2100Z: Solar activity was very low. No flares occurred during the past 24 hours. Region 971 (N03W06) is a small C-type sunspot group and was quiet and stable.

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

IIA. Geophysical Activity Summary 28/2100Z to 29/2100Z: The geomagnetic field was at active to minor storm levels from the beginning of the period through 29/1200Z, and was mostly unsettled thereafter. Real-time solar wind observations at ACE show that the activity was due to the ongoing influence of a high speed solar wind stream from a coronal hole. The greater than 2 MeV electron flux at geosynchronous orbit reached high levels during the past 24 hours.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be mostly unsettled for the first day (30 September) with a chance for isolated active periods. Activity should decline to quiet to unsettled for the second and third days (01-02 October).

III. Event Probabilities 30 Sep-02 Oct

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

IV. Penticton 10.7 cm Flux

• Observed 29 Sep 068
• Predicted 30 Sep-02 Oct 068/068/068
• 90 Day Mean 29 Sep 069

V. Geomagnetic A Indices

• Observed Afr/Ap 28 Sep 015/021
• Estimated Afr/Ap 29 Sep 020/025
• Predicted Afr/Ap 30 Sep-02 Oct 010/015-007/008-007/010

VI. Geomagnetic Activity Probabilities 30 Sep-02 Oct

A. Middle Latitudes

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

B. High Latitudes

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