:Product: 0427RSGA.txt :Issued: 2011 Apr 27 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 117 Issued at 2200Z on 27 Apr 2011 IA. Analysis of Solar Active Regions and Activity from 26/2100Z to 27/2100Z: Solar activity has been at low levels for the past 24 hours. New Region 1201 (N16E40), grew rapidly early in the period, producing a C2 flare at 27/0301Z with a non-Earth directed CME. A Type II radio sweep, with a shock velocity of 845 km/s, was also associated with this event. Region 1201 has since decayed and is now spotless plage. A second, back-sided CME, first visible in LASCO C2 imagery at 27/0800Z, was also observed during the period. Neither CME is expected to become geoeffective. Region 1199 (N21W34) continues to grow and evolve. IB. Solar Activity Forecast: Solar activity is expected to be at very low to low levels for the next three days (28-30 April). IIA. Geophysical Activity Summary 26/2100Z to 27/2100Z: The geomagnetic field has been at quiet levels for the past 24 hours. IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at predominantly quiet levels for the next 2 days (28-29 April). Unsettled to active levels are expected on day three (30 April) as a recurrent coronal hole high-speed stream becomes geoeffective. III. Event Probabilities 28 Apr-30 Apr Class M 05/05/05 Class X 01/01/01 Proton 01/01/01 PCAF green IV. Penticton 10.7 cm Flux Observed 27 Apr 108 Predicted 28 Apr-30 Apr 105/105/105 90 Day Mean 27 Apr 107 V. Geomagnetic A Indices Observed Afr/Ap 26 Apr 001/003 Estimated Afr/Ap 27 Apr 001/003 Predicted Afr/Ap 28 Apr-30 Apr 005/005-005/005-010/010 VI. Geomagnetic Activity Probabilities 28 Apr-30 Apr A. Middle Latitudes Active 05/10/35 Minor storm 01/01/05 Major-severe storm 01/01/01 B. High Latitudes Active 05/10/35 Minor storm 01/01/05 Major-severe storm 01/01/01