:Product: 20000825RSGA.txt :Issued: 2000 Aug 25 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 238 ISSUED AT 2200Z ON 25 AUG 2000 IA. ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM 24/2100Z TO 25/2100Z: SOLAR ACTIVITY BECAME MODERATE. REGION 9143 (S19E59) PRODUCED AN M1/1N AT 25/1435Z. THIS EVENT WAS ACCOMPANIED BY A TYPE II/IV AND A 130 SFU BURST AT 2695 MHZ. A LARGE DENSE MASS EJECTION FOLLOWED THE EVENT AND WAS SEEN TO PROPAGATE PRIMARILY OFF THE EAST LIMB NEAR THE EQUATOR. PRIOR TO THIS EVENT, REGION 9143 WAS PREDOMINANTLY STABLE. A LARGE FILAMENT NEAR N37W21 ERUPTED BETWEEN 25/0955-1123Z. THIS FILAMENT ELEVATED AND BECAME MORE DENSE FOR AT LEAST A DAY BEFORE THE ERUPTION. A SMALL REGION BEGAN TO EMERGE RAPIDLY NEAR N25E14 AND WAS NUMBERED AS NEW REGION 9144. IB. SOLAR ACTIVITY FORECAST: SOLAR ACTIVITY SHOULD BE PREDOMINANTLY LOW. OBVIOUSLY, REGION 9143 IS CAPABLE OF GENERATING M-CLASS EVENTS. HOWEVER, THE LACK OF OBVIOUS GROWTH AND MAGNETIC SIMPLICITY ARGUE FOR ONLY ISOLATED M-CLASS EVENTS FROM THIS REGION. IIA. GEOPHYSICAL ACTIVITY SUMMARY 24/2100Z TO 25/2100Z: THE GEOMAGNETIC FIELD WAS QUIET. SOLAR WIND VELOCITY WAS STEADY NEAR 400 KM/S. IIB. GEOPHYSICAL ACTIVITY FORECAST: THE GEOMAGNETIC FIELD IS EXPECTED TO BE QUIET TO UNSETTLED FOR THE NEXT THREE DAYS. AT THIS TIME, THE MASS EJECTION OBSERVED TODAY IS NOT PROJECTED TO IMPACT THE EARTH. III. EVENT PROBABILITIES 26 AUG-28 AUG CLASS M 30/30/30 CLASS X 01/01/01 PROTON 01/01/01 PCAF GREEN IV. PENTICTON 10.7 CM FLUX OBSERVED 25 AUG 133 PREDICTED 26 AUG-28 AUG 135/137/140 90 DAY MEAN 25 AUG 181 V. GEOMAGNETIC A INDICES OBSERVED AFR/AP 24 AUG 007/010 ESTIMATED AFR/AP 25 AUG 003/008 PREDICTED AFR/AP 26 AUG-28 AUG 005/008-005/008-008/010 VI. GEOMAGNETIC ACTIVITY PROBABILITIES 26 AUG-28 AUG A. MIDDLE LATITUDES ACTIVE 10/10/20 MINOR STORM 05/05/10 MAJOR-SEVERE STORM 01/01/05 B. HIGH LATITUDES ACTIVE 10/10/25 MINOR STORM 05/05/10 MAJOR-SEVERE STORM 01/01/05