:Product: 19980916RSGA.txt :Issued: 1998 Sep 16 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 259 ISSUED AT 2200Z ON 16 SEP 1998 IA. ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM 15/2100Z TO 16/2100Z: SOLAR ACTIVITY HAS BEEN VERY LOW FOR THE PAST 24 HOURS. THREE NEW REGIONS WERE NUMBERED: REGION 8336 (S30E52), REGION 8337 (S39E42), AND REGION 8338 (N31E81). ALL ARE MAGNETICALLY SIMPLE. SURGING WAS REPORTED ON THE WEST LIMB NEAR DEPARTED REGIONS 8326 (N18) AND 8334 (S24), AND ON THE EAST LIMB NEAR N41. THE REMAINDER OF THE LIMB AND THE NUMBERED REGIONS ON THE DISK WERE QUIET OR UNREMARKABLE. IB. SOLAR ACTIVITY FORECAST: SOLAR ACTIVITY IS EXPECTED TO BE LOW BASED UPON REGIONS PRESENTLY VISIBLE. HOWEVER, RETURNING REGIONS OR DEVELOPMENT IN REGIONS NOW ON THE DISK COULD PROVIDE OPPORTUNITY FOR ISOLATED M-CLASS FLARES OVER THE FORECAST PERIOD. IIA. GEOPHYSICAL ACTIVITY SUMMARY FROM 15/2100Z TO 16/2100Z: THE GEOMAGNETIC FIELD HAS BEEN QUIET FOR THE PAST 24 HOURS. IIB. GEOPHYSICAL ACTIVITY FORECAST: THE GEOMAGNETIC FIELD IS EXPECTED TO PERSIST AT QUIET LEVELS TOMORROW, BECOMING UNSETTLED TO OCCASIONALLY ACTIVE BY THE END OF THE FORECAST PERIOD DUE TO POSSIBLE EFFECTS FROM A CORONAL HOLE AND SEVERAL SMALL FILAMENT DISAPPEARANCES BETWEEN SEPTEMBER 11-13. III. EVENT PROBABILITIES 17 SEP-19 SEP CLASS M 15/15/15 CLASS X 01/01/01 PROTON 01/01/01 PCAF GREEN IV. PENTICTON 10.7 CM FLUX OBSERVED 16 SEP 119 PREDICTED 17 SEP-19 SEP 125/130/135 90 DAY MEAN 16 SEP 126 V. GEOMAGNETIC A INDICES OBSERVED AFR/AP 15 SEP 005/007 ESTIMATED AFR/AP 16 SEP 005/010 PREDICTED AFR/AP 17 SEP-19 SEP 005/010-010/012-010/012 VI. GEOMAGNETIC ACTIVITY PROBABILITIES 17 SEP-19 SEP A. MIDDLE LATITUDES ACTIVE 30/30/30 MINOR STORM 15/10/10 MAJOR-SEVERE STORM 05/05/05 B. HIGH LATITUDES ACTIVE 10/15/25 MINOR STORM 05/05/10 MAJOR-SEVERE STORM 01/05/05