:Product: 1225RSGA.txt :Issued: 2009 Dec 25 2200 UTC # Prepared jointly by the U.S. Dept. of Commerce, NOAA, # Space Weather Prediction Center and the U.S. Air Force. # Joint USAF/NOAA Report of Solar and Geophysical Activity SDF Number 359 Issued at 2200Z on 25 Dec 2009 IA. Analysis of Solar Active Regions and Activity from 24/2100Z to 25/2100Z: Solar activity was very low. No flares were observed. The visible disk was spotless. IB. Solar Activity Forecast: Solar activity is expected to be very low. IIA. Geophysical Activity Summary 24/2100Z to 25/2100Z: The geomagnetic field was quiet. Solar wind observations from the ACE satellite decreased gradually after 24/2235Z, from 380 km/s to 282 km/s at 25/1457Z. Velocities then increased to 354 km/s at 25/1708Z as the density increased to a peak of 13 p/cc. The interplanetary magnetic field (IMF) increased, with the total field reaching +10 nT at 25/1852Z. The southward component of the IMF ranged between -8 nT and +7 nT, with the peak of -8 nT at 25/1609Z. This activity is consistent with the arrival of the partial halo coronal mass ejection (CME) observed on 22 December. IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be predominantly quiet, with isolated unsettled periods possible at high latitudes, on day one (26 December). Quiet levels are expected on days two and three (27-28 December). III. Event Probabilities 26 Dec-28 Dec Class M 01/01/01 Class X 01/01/01 Proton 01/01/01 PCAF Green IV. Penticton 10.7 cm Flux Observed 25 Dec 076 Predicted 26 Dec-28 Dec 072/072/072 90 Day Mean 25 Dec 074 V. Geomagnetic A Indices Observed Afr/Ap 24 Dec 001/002 Estimated Afr/Ap 25 Dec 003/005 Predicted Afr/Ap 26 Dec-28 Dec 007/007-005/005-005/005 VI. Geomagnetic Activity Probabilities 26 Dec-28 Dec A. Middle Latitudes Active 10/05/05 Minor storm 01/01/01 Major-severe storm 01/01/01 B. High Latitudes Active 15/05/05 Minor storm 01/01/01 Major-severe storm 01/01/01