:Product: 19980924RSGA.txt :Issued: 1998 Sep 24 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 267 ISSUED AT 2200Z ON 24 SEP 1998 IA. ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM 23/2100Z TO 24/2100Z: SOLAR ACTIVITY WAS LOW. THE TWO ACTIVE REGIONS WERE 8340 (N20W15) AND 8344 (S20W04). BOTH REGIONS PRODUCE 2 C-CLASS EVENTS EACH. BOTH REGIONS HAVE ALSO DEVELOPED INTO COMPLEX BETA-GAMMA-DELTA MAGNETIC CONFIGURATIONS. REGION 8340 HAS SHOWN PLAGE FLUCTUATIONS AND POINT BRIGHTENINGS FOR MOST OF THE DAY. THE REST OF THE REGIONS WERE STABLE AND MOSTLY QUIET. TWO NEW REGIONS WERE NUMBERED TODAY: REGION 8345 (N22W06) AND REGION 8346 (S30E41). THERE ARE NOW 10 SPOT GROUPS ON THE DISK. IB. SOLAR ACTIVITY FORECAST: SOLAR ACTIVITY IS EXPECTED TO CONTINUE TO BE LOW TO MODERATE. REGIONS 8340 AND 8344 CAN BE EXPECTED TO CONTINUE TO PRODUCE C-CLASS FLARES AND POSSIBLE M-CLASS EVENTS. IIA. GEOPHYSICAL ACTIVITY SUMMARY FROM 23/2100Z TO 24/2100Z: GEOMAGNETIC ACTIVITY WAS QUIET TO ACTIVE AT MIDDLE LATITUDES AND UNSETTLED TO MINOR STORM CONDITIONS AT HIGHER LATITUDES. IIB. GEOPHYSICAL ACTIVITY FORECAST: THE GEOMAGNETIC FIELD IS EXPECTED TO BE UNSETTLED TO ACTIVE WITH POSSIBLE PERIODS OF MINOR STORM LEVELS ESPECIALLY AT HIGHER LATITUDES. III. EVENT PROBABILITIES 25 SEP-27 SEP CLASS M 40/40/40 CLASS X 10/10/10 PROTON 05/05/01 PCAF GREEN IV. PENTICTON 10.7 CM FLUX OBSERVED 24 SEP 135 PREDICTED 25 SEP-27 SEP 150/155/155 90 DAY MEAN 24 SEP 129 V. GEOMAGNETIC A INDICES OBSERVED AFR/AP 23 SEP 010/129 ESTIMATED AFR/AP 24 SEP 020/020 PREDICTED AFR/AP 25 SEP-27 SEP 030/025-020/030-015/020 VI. GEOMAGNETIC ACTIVITY PROBABILITIES 25 SEP-27 SEP A. MIDDLE LATITUDES ACTIVE 50/30/25 MINOR STORM 30/10/10 MAJOR-SEVERE STORM 10/05/01 B. HIGH LATITUDES ACTIVE 65/50/40 MINOR STORM 30/20/15 MAJOR-SEVERE STORM 05/01/01