Joint USAF/NOAA Report of Solar and Geophysical Activity 15 Dec 2006

Product: Report of Solar-Geophysical Activity
Issued: 2006 Dec 15 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 349 Issued at 2200Z on 15 Dec 2006

IA. Analysis of Solar Active Regions and Activity from 14/2100Z to 15/2100Z: Solar activity was high. Region 930 (S06W59) produced an X1.5/2B solar flare with a 510 sfu 10 cm radio burst at 14/2215Z. Type II (1277 km/s) and Type IV radio sweeps were associated with this event. The flare was accompanied by a frontside, asymmetrical, full halo CME with an estimated plane-of-sky speed of 900 km/s. Ejecta of this CME seems to be predominately from the southwest sector of the halo.

IB. Solar Activity Forecast: Solar activity is expected to be moderate to high. Isolated X-class flares from Region 930 remain a possibility.

IIA. Geophysical Activity Summary 14/2100Z to 15/2100Z: The geomagnetic field reached severe storm levels. A 100 MeV proton event commenced 14/2255Z, reached a 2.3 pfu maximum at 15/0015Z and ended 15/0325Z. The greater than 10 MeV proton event that commenced 13/0310Z, reached a 698 pfu maximum at 13/0925Z and ended at 15/1620Z. The greater than 2 MeV electrons reached high levels today. Solar wind speed has decreased to 600 km/s.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to reach major to severe storm levels. A glancing blow from the CME late in the day of 14 December is expected to impact the geomagnetic field by mid to late UTC on day one of the forecast period (December 16). Minor to major storm levels are expected to continue into December 17. The disturbance is expected to abate to quiet to unsettled conditions for the final day of the forecast period (December 18).

III. Event Probabilities 16 Dec-18 Dec

• Class M 65/65/65
• Class X 35/35/35
• Proton 01/01/01
• PCAF yellow

IV. Penticton 10.7 cm Flux

• Observed 15 Dec 087
• Predicted 16 Dec-18 Dec 090/090/090
• 90 Day Mean 15 Dec 081

V. Geomagnetic A Indices

• Observed Afr/Ap 14 Dec 030/063
• Estimated Afr/Ap 15 Dec 060/100
• Predicted Afr/Ap 16 Dec-18 Dec 040/045-045/070-008/010

VI. Geomagnetic Activity Probabilities 16 Dec-18 Dec

A. Middle Latitudes

• Active 10/10/30
• Minor storm 35/35/15
• Major-severe storm 50/50/05

B. High Latitudes

• Active 05/05/30
• Minor storm 30/30/20
• Major-severe storm 60/60/10