Joint USAF/NOAA Report of Solar and Geophysical Activity 28 Dec 2005

Product: Report of Solar-Geophysical Activity
Issued: 2005 Dec 28 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 362 Issued at 2200Z on 28 Dec 2005

IA. Analysis of Solar Active Regions and Activity from 27/2100Z to 28/2100Z: Solar activity was at very low levels today. Region 843 produced the largest flare of the period, a B9 x-ray flare which occurred at 28/1125Z. No new regions were numbered today.

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

IIA. Geophysical Activity Summary 27/2100Z to 28/2100Z: The geomagnetic field ranged from unsettled to minor storm levels. A recurrent trans-equatorial high speed coronal hole stream was responsible for the elevated conditions. 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 predominantly unsettled to active levels with isolated minor storm periods possible through 29 December. A return to quiet to unsettled levels is expected on 30 and 31 December as the coronal hole moves out of geoeffective position.

III. Event Probabilities 29 Dec-31 Dec

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

IV. Penticton 10.7 cm Flux

• Observed 28 Dec 089
• Predicted 29 Dec-31 Dec 090/090/090
• 90 Day Mean 28 Dec 084

V. Geomagnetic A Indices

• Observed Afr/Ap 27 Dec 010/018
• Estimated Afr/Ap 28 Dec 015/020
• Predicted Afr/Ap 29 Dec-31 Dec 012/020-008/015-005/010

VI. Geomagnetic Activity Probabilities 29 Dec-31 Dec A. Middle Latitudes

• Active 25/20/15
• Minor storm 10/05/01
• Major-severe storm 05/01/01

B. High Latitudes

• Active 40/35/25
• Minor storm 25/15/10
• Major-severe storm 10/05/05