:Product: 0718RSGA.txt :Issued: 2011 Jul 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 Report of Solar and Geophysical Activity SDF Number 199 Issued at 2200Z on 18 Jul 2011 IA. Analysis of Solar Active Regions and Activity from 17/2100Z to 18/2100Z: Solar activity has been at low levels for the past 24 hours. Region 1254 (S22E11) produced the largest event of the period, a C1/Sf flare at 18/1028Z. Two new regions were numbered today: Region 1258 (N11W37) emerged on the disk and is magnetically classified as a beta and Region 1259 (N26E69) rotated on the disk as a Dao-beta group. Early in the period, two CMEs were observed in LASCO C2 and C3 imagery but neither appear to be Earth directed. IB. Solar Activity Forecast: Solar activity is expected to be at very low to low levels for the next two days (19-20 July). Activity is expected to decrease to very low levels on day three (21 July) as Region 1257 (N20W69) rotates off the west limb. IIA. Geophysical Activity Summary 17/2100Z to 18/2100Z: The geomagnetic field was at quiet to unsettled levels for the past 24 hours. Measurements by the ACE spacecraft indicated a solar sector boundary crossing (from positive to negative) at around 18/0230Z. Following the crossing, coronal hole high-speed stream characteristics were monitored, with solar wind speeds increasing from 370 km/s to around 460 km/s. IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to unsettled levels on day one (19 July), and at quiet to active levels on days two and three (20-21 July), as another coronal hole high-speed stream becomes geoeffective. III. Event Probabilities 19 Jul-21 Jul Class M 10/10/10 Class X 01/01/01 Proton 01/01/01 PCAF green IV. Penticton 10.7 cm Flux Observed 18 Jul 102 Predicted 19 Jul-21 Jul 102/100/096 90 Day Mean 18 Jul 097 V. Geomagnetic A Indices Observed Afr/Ap 17 Jul 003/005 Estimated Afr/Ap 18 Jul 006/008 Predicted Afr/Ap 19 Jul-21 Jul 010/010-012/012-012/012 VI. Geomagnetic Activity Probabilities 19 Jul-21 Jul A. Middle Latitudes Active 25/30/30 Minor storm 01/05/05 Major-severe storm 01/01/01 B. High Latitudes Active 30/35/35 Minor storm 01/10/10 Major-severe storm 01/01/01