:Product: 19970726RSGA.txt :Issued: 1997 Jul 26 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 207 ISSUED AT 2200Z ON 26 JUL 1997 IA. ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM 25/2100Z TO 26/2100Z: SOLAR ACTIVITY WAS VERY LOW. ONLY A FEW B-CLASS EVENTS WERE OBSERVED DURING THE PERIOD. REGION 8065 (N17W70) HAS BECOME STABLE IN THE PAST 24 HOURS. THE GROUP'S MAGNETIC STRUCTURE HAS SIMPLIFIED SIGNIFICANTLY AND IT NOW SHOWS A SIMPLE BETA CONFIGURATION. IB. SOLAR ACTIVITY FORECAST: SOLAR ACTIVITY IS EXPECTED TO BE VERY LOW. THERE IS A CHANCE FOR AN ISOLATED C-CLASS EVENT OVER THE NEXT THREE DAYS. IIA. GEOPHYSICAL ACTIVITY SUMMARY FROM 25/2100Z TO 26/2100Z: THE GEOMAGNETIC FIELD WAS QUIET. IIB. GEOPHYSICAL ACTIVITY FORECAST: THE GEOMAGNETIC FIELD IS EXPECTED TO BE QUIET TO UNSETTLED FOR THE NEXT 24 HOURS. AN INCREASE IS EXPECTED SOMETIME BETWEEN LATE TOMORROW AND EARLY ON DAY THREE DUE TO EFFECTS FROM A POSSIBLE TRANSIENT ASSOCIATED WITH YESTERDAY'S LONG DURATION X-RAY EVENT. IN ADDITION TO THIS, THERE IS A POSSIBILITY FOR EFFECTS FROM A CORONAL HOLE BEGINNING ON THE THIRD DAY. MOSTLY UNSETTLED LEVELS (BUT WITH POSSIBILITY FOR ACTIVE PERIODS) ARE EXPECTED ON DAY 2 AND UNSETTLED TO ACTIVE LEVELS ARE FORECAST FOR DAY THREE. III. EVENT PROBABILITIES 27 JUL-29 JUL CLASS M 05/05/05 CLASS X 01/01/01 PROTON 01/01/01 PCAF GREEN IV. PENTICTON 10.7 CM FLUX OBSERVED 26 JUL 077 PREDICTED 27 JUL-29 JUL 075/075/072 90 DAY MEAN 26 JUL 073 V. GEOMAGNETIC A INDICES OBSERVED AFR/AP 25 JUL 008/005 ESTIMATED AFR/AP 26 JUL 005/005 PREDICTED AFR/AP 27 JUL-29 JUL 010/008-015/012-015/020 VI. GEOMAGNETIC ACTIVITY PROBABILITIES 27 JUL-29 JUL A. MIDDLE LATITUDES ACTIVE 15/25/20 MINOR STORM 10/20/10 MAJOR-SEVERE STORM 05/10/05 B. HIGH LATITUDES ACTIVE 20/30/30 MINOR STORM 10/25/25 MAJOR-SEVERE STORM 05/15/15