:Product: 1218RSGA.txt :Issued: 2017 Dec 18 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 Solar Geophysical Activity Report and Forecast SDF Number 352 Issued at 2200Z on 18 Dec 2017 IA. Analysis of Solar Active Regions and Activity from 17/2100Z to 18/2100Z: Solar activity has been at very low levels for the past 24 hours. There are currently 0 numbered sunspot regions on the disk. IB. Solar Activity Forecast: Solar activity is expected to be very low on days one, two, and three (19 Dec, 20 Dec, 21 Dec). IIA. Geophysical Activity Summary 17/2100Z to 18/2100Z: The geomagnetic field has been at quiet to active levels for the past 24 hours. Solar wind speed reached a peak of 671 km/s at 18/0329Z. Total IMF reached 10 nT at 17/2133Z. The maximum southward component of Bz reached -8 nT at 17/2131Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 5978 pfu. IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to active levels on day one (19 Dec), unsettled levels on day two (20 Dec) and quiet to unsettled levels on day three (21 Dec). III. Event probabilities 19 Dec-21 Dec Class M 01/01/01 Class X 01/01/01 Proton 01/01/01 PCAF green IV. Penticton 10.7 cm Flux Observed 18 Dec 072 Predicted 19 Dec-21 Dec 072/072/072 90 Day Mean 18 Dec 075 V. Geomagnetic A Indices Observed Afr/Ap 17 Dec 016/023 Estimated Afr/Ap 18 Dec 016/021 Predicted Afr/Ap 19 Dec-21 Dec 015/015-011/012-007/008 VI. Geomagnetic Activity Probabilities 19 Dec-21 Dec A. Middle Latitudes Active 25/20/15 Minor Storm 10/10/05 Major-severe storm 01/01/01 B. High Latitudes Active 15/15/10 Minor Storm 30/25/20 Major-severe storm 35/30/20