:Product: 19980509RSGA.txt :Issued: 1998 May 09 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 129 ISSUED AT 2200Z ON 09 MAY 1998 IA. ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM 08/2100Z TO 09/2100Z: SOLAR ACTIVITY INCREASED TO HIGH LEVELS. AN M7 X-RAY FLARE WAS DETECTED AT 09/0340UT. A MAJOR TYPE IV RADIO SWEEP, A 210 SFU TENFLARE, AND A CORONAL MASS EJECTION (CME) ACCOMPANIED THE FLARE. THE CME WAS NOT EARTH-DIRECTED. OLD REGION 8210, NOW A DAY AND A HALF BEYOND THE WEST LIMB, WAS THE LIKELY SOURCE OF THE FLARE. REGION 8214 (N27W74) PRODUCED ISOLATED C-CLASS FLARES AND SHOWED LITTLE CHANGE IN SIZE OR SPOT NUMBER, BUT ANALYSIS WAS DIFFICULT DUE TO LIMB PROXIMITY. REGION 8218 (S19W34) WAS STABLE. REGION 8213 (S22W89) PRODUCED AN ERUPTIVE PROMINENCE (VERTICAL EXTENT 0.3 SOLAR RADII) AS IT CROSSED THE WEST LIMB. NO NEW REGIONS WERE ASSIGNED. IB. SOLAR ACTIVITY FORECAST: SOLAR ACTIVITY IS EXPECTED TO BE MODERATE. REGIONS 8214 AND 8218 PROVIDE A FAIR CHANCE FOR ISOLATED M-CLASS ACTIVITY. IIA. GEOPHYSICAL ACTIVITY SUMMARY FROM 08/2100Z TO 09/2100Z: THE GEOMAGNETIC FIELD WAS QUIET TO UNSETTLED. A GREATER THAN 10 MEV PROTON ENHANCEMENT FOLLOWED THE M7 FLARE. IT BEGAN NEAR 09/0600UT AND GRADUALLY INCREASED THROUGH THE PERIOD. FLUXES WERE NEAR EVENT THRESHOLD AT THE END OF THE PERIOD. THE GREATER THAN 2 MEV ELECTRON FLUX WAS AT MODERATE TO HIGH LEVELS. IIB. GEOPHYSICAL ACTIVITY FORECAST: THE GEOMAGNETIC FIELD IS EXPECTED TO BE MOSTLY UNSETTLED THROUGH THE PERIOD. THE GREATER THAN 10 MEV PROTON FLUX WILL LIKELY REACH EVENT THRESHOLD EARLY IN THE PERIOD, THEN GRADUALLY DECLINE TO BACKGROUND LEVEL. III. EVENT PROBABILITIES 10 MAY-12 MAY CLASS M 50/40/20 CLASS X 05/05/01 PROTON 05/05/01 PCAF GREEN IV. PENTICTON 10.7 CM FLUX OBSERVED 09 MAY 111 PREDICTED 10 MAY-12 MAY 110/104/100 90 DAY MEAN 09 MAY 107 V. GEOMAGNETIC A INDICES OBSERVED AFR/AP 08 MAY 024/020 ESTIMATED AFR/AP 09 MAY 010/015 PREDICTED AFR/AP 10 MAY-12 MAY 010/010-012/010-012/010 VI. GEOMAGNETIC ACTIVITY PROBABILITIES 10 MAY-12 MAY A. MIDDLE LATITUDES ACTIVE 25/30/30 MINOR STORM 10/10/10 MAJOR-SEVERE STORM 01/01/01 B. HIGH LATITUDES ACTIVE 30/35/35 MINOR STORM 10/20/20 MAJOR-SEVERE STORM 01/01/01