:Product: 20000915RSGA.txt :Issued: 2000 Sep 15 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 15 SEP 2000 IA. ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM 14/2100Z TO 15/2100Z: SOLAR ACTIVITY WAS MODERATE. REGION 9165 (N14E01) WAS THE MOST PRODUCTIVE SUNSPOT GROUP PRODUCING AN M2/SF AT 15/0532 UTC, AN M2/1N AT 15/1437 UTC, AND SEVERAL C-CLASS FLARES. THIS AREA CONTINUES TO GROW IN SUNSPOT AREA AND MAGNETIC COMPLEXITY. REGION 9166 (S14E62) IS THE OTHER DISK AREA OF NOTE AND IS A COMPACT D-TYPE SUNSPOT GROUP. SO FAR 9166 HAS ONLY PRODUCED LOW-LEVEL C-CLASS FLARES. IB. SOLAR ACTIVITY FORECAST: SOLAR ACTIVITY IS EXPECTED TO BE MODERATE. ADDITIONAL M-CLASS FLARES ARE LIKELY IN REGION 9165 AND C-CLASS FLARES ARE POSSIBLE IN REGION 9166. IIA. GEOPHYSICAL ACTIVITY SUMMARY 14/2100Z TO 15/2100Z: THE GEOMAGNETIC FIELD WAS QUIET TO ACTIVE. A SHOCK IN THE SOLAR WIND WAS DETECTED BY THE NASA ACE SPACECRAFT AT ABOUT 15/0400 UTC. THE SHOCK HAD A MODERATELY STRONG INCREASE IN DENSITY BUT ONLY SLIGHT ENHANCEMENT IN REDIAL SPEED AND TOTAL IMF. BZ WAS STRONGLY POSITIVE FOR SEVERAL HOURS FOLLOWING THE SHOCK PASSAGE AND HAS JUST TURN SOUTHWARD AT ABOUT 15/1900 UTC. EVIDENCE SUGGESTS THAT THIS SHOCK IS ASSOCIATED WITH THE CME AND ERUPTIVE FILAMENT ON SEPTEMBER 12. THE GREATER THAN 10 MEV PROTON EVENT CONTINUES IN PROGRESS. THE CURRENT FLUX (2130 UTC) IS ABOUT 10 PFU AND IS SLOWLY DROPPING. IIB. GEOPHYSICAL ACTIVITY FORECAST: THE GEOMAGNETIC FIELD IS EXPECTED TO BE PREDOMINATELY QUIET TO UNSETTLED WITH THE POSSIBILITY OF ISOLATED ACTIVE CONDITIONS AS THE CME STRUCTURE PASSES THE EARTH. THE GREATER THAN 10 MEV PROTON EVENT IS EXPECTED TO END DURING THE FIRST DAY OF THE FORECAST PERIOD. III. EVENT PROBABILITIES 16 SEP-18 SEP CLASS M 50/50/50 CLASS X 05/05/05 PROTON 05/01/01 PCAF IN PROGRESS IV. PENTICTON 10.7 CM FLUX OBSERVED 15 SEP 159 PREDICTED 16 SEP-18 SEP 165/170/175 90 DAY MEAN 15 SEP 177 V. GEOMAGNETIC A INDICES OBSERVED AFR/AP 14 SEP 003/006 ESTIMATED AFR/AP 15 SEP 010/009 PREDICTED AFR/AP 16 SEP-18 SEP 010/015-010/010-010/010 VI. GEOMAGNETIC ACTIVITY PROBABILITIES 16 SEP-18 SEP A. MIDDLE LATITUDES ACTIVE 15/15/15 MINOR STORM 10/10/10 MAJOR-SEVERE STORM 01/01/01 B. HIGH LATITUDES ACTIVE 15/15/15 MINOR STORM 10/10/10 MAJOR-SEVERE STORM 01/01/01