:Product: 19990618RSGA.txt :Issued: 1999 Jun 18 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 169 ISSUED AT 2200Z ON 18 JUN 1999 IA. ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM 17/2100Z TO 18/2100Z: SOLAR ACTIVITY RETURNED TO LOW LEVELS. THE LARGEST EVENT OF THE PERIOD WAS A C7/1N FROM REGION 8585 (N38E05). SEVERAL OTHER SMALL TO MIDDLE LEVEL C-CLASS EVENTS WERE OBSERVED. SOHO DATA INDICATED THAT MOST OF THESE EVENTS WERE FROM BEYOND THE NORTHWEST LIMB. HOWEVER, A MODERATE DURATION C5 X-RAY EVENT WAS OBSERVED AT 18/1657Z THAT CORRELATED WITH A FLARE BRIGHT MOUND NEAR NE25. LAST ROTATION, THIS AREA WAS COMPRISED OF SEVERAL ACTIVE REGIONS THAT PRODUCED FREQUENT C-CLASS AND OCCASIONAL M-CLASS EVENTS. OTHER DISK REGIONS EXHIBITED ONLY MINOR EVOLUTION. IB. SOLAR ACTIVITY FORECAST: SOLAR ACTIVITY SHOULD BE GENERALLY LOW FOR THE NEXT THREE DAYS. M-CLASS EVENTS ARE POSSIBLE FROM THE AREA ROTATING OVER THE NORTHEAST LIMB. A BETTER DETERMINATION OF THE FLARE POTENTIAL OF THIS AREA MUST AWAIT ITS APPEARANCE TO THE VISIBLE DISK. IIA. GEOPHYSICAL ACTIVITY SUMMARY FROM 17/2100Z TO 18/2100Z: THE GEOMAGNETIC FIELD WAS QUIET. IIB. GEOPHYSICAL ACTIVITY FORECAST: THE GEOMAGNETIC FIELD IS EXPECTED TO BE QUIET TO SLIGHTLY UNSETTLED FOR THE NEXT THREE DAYS. III. EVENT PROBABILITIES 19 JUN-21 JUN CLASS M 25/25/25 CLASS X 05/05/05 PROTON 01/01/01 PCAF GREEN IV. PENTICTON 10.7 CM FLUX OBSERVED 18 JUN 147 PREDICTED 19 JUN-21 JUN 150/153/156 90 DAY MEAN 18 JUN 136 V. GEOMAGNETIC A INDICES OBSERVED AFR/AP 17 JUN 006/007 ESTIMATED AFR/AP 18 JUN 005/008 PREDICTED AFR/AP 19 JUN-21 JUN 007/007-007/007-007/007 VI. GEOMAGNETIC ACTIVITY PROBABILITIES 19 JUN-21 JUN A. MIDDLE LATITUDES ACTIVE 10/10/10 MINOR STORM 05/05/05 MAJOR-SEVERE STORM 01/01/01 B. HIGH LATITUDES ACTIVE 10/10/15 MINOR STORM 05/05/05 MAJOR-SEVERE STORM 01/01/01