Joint USAF/NOAA Report of Solar and Geophysical Activity 23 Sep 2005

Prepared jointly by the U.S. Dept. of Commerce, NOAA,
Space Environment Center and the U.S. Air Force.
Updated 2005 Sep 23 2204 UTC

Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 266 Issued at 2200Z on 23 Sep 2005

IA. Analysis of Solar Active Regions and Activity from 22/2100Z to 23/2100Z: Solar activity increased to low levels. Region 810 (N09W06) produced a single C1/Sf flare today at 0559Z. This region underwent gradual growth during the period and is currently depicting magnetic beta-gamma characteristics. Newly numbered Region 812 (S01E73), was responsible for an eruptive prominence on the east solar limb just prior to becoming a visible CSO beta sunspot group.

IB. Solar Activity Forecast: Solar activity is expected to be at very low to low levels. Region 810 has the complexity to produce isolated C-class flares.

IIA. Geophysical Activity Summary 22/2100Z to 23/2100Z: The geomagnetic field was at predominantly quiet to unsettled levels. A brief active period was observed at the Boulder magnetometer between 23/0600Z and 0900Z. 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 at quiet to unsettled levels.

III. Event Probabilities 24 Sep-26 Sep

• Class M 20/20/20
• Class X 01/01/01
• Proton 01/01/01
• PCAF green

IV. Penticton 10.7 cm Flux

• Observed 23 Sep 083
• Predicted 24 Sep-26 Sep 085/085/085
• 90 Day Mean 23 Sep 094

V. Geomagnetic A Indices

• Observed Afr/Ap 22 Sep 006/008
• Estimated Afr/Ap 23 Sep 005/008
• Predicted Afr/Ap 24 Sep-26 Sep 005/008-005/008-005/008

VI. Geomagnetic Activity Probabilities 24 Sep-26 Sep

A. Middle Latitudes

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

B. High Latitudes

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