:Product: 19980127RSGA.txt :Issued: 1998 Jan 27 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 027 ISSUED AT 2200Z ON 27 JAN 1998 IA. ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM 26/2100Z TO 27/2100Z: SOLAR ACTIVITY WAS LOW. REGION 8142 (S21W65) PRODUCED THE DAY'S ONLY C-CLASS FLARE, A C5/SN AT 26/2235UT. A TYPE II RADIO SWEEP ACCOMPANIED THE FLARE (EST. SHOCK VEL. 700 - 900 KM/SEC). ISOLATED B-CLASS SUBFLARES OCCURRED DURING THE REMAINDER OF THE PERIOD. REGION 8143 (S35E10) APPEARED TO STABILIZE WHILE MAINTAINING A MODERATELY COMPLEX MAGNETIC STRUCTURE. NO NEW REGIONS WERE ASSIGNED. IB. SOLAR ACTIVITY FORECAST: SOLAR ACTIV ITY IS EXPECTED TO REMAIN LOW. REGIONS 8142 AND 8143 COULD PRODUCE ISOLATED C-CLASS FLARES. THERE IS ALSO A SLIGHT CHANCE FOR AN M-CLASS FLARE FROM EITHER REGION. IIA. GEOPHYSICAL ACTIVITY SUMMARY FROM 26/2100Z TO 27/2100Z: THE GEOMAGNETIC FIELD WAS QUIET TO UNSETTLED. THE UNSETTLED PERIODS WERE LIMITED TO HIGH LATITUDES. IIB. GEOPHYSICAL ACTIVITY FORECAST: THE GEOMAGNETIC FIELD IS EXPECTED TO BE MOSTLY QUIET THROUGH 28 JANUARY. A DISTURBANCE IS EXPECTED DURING 29 - 30 JANUARY IN RESPONSE TO THE PARTIAL-HALO CME THAT OCCURRED ON 25 JANUARY. UNSETTLED TO MINOR STORM LEVELS ARE EXPECTED DURING THE DISTURBANCE. III. EVENT PROBABILITIES 28 JAN-30 JAN CLASS M 10/10/10 CLASS X 01/01/01 PROTON 01/01/01 PCAF GREEN IV. PENTICTON 10.7 CM FLUX OBSERVED 27 JAN 101 PREDICTED 28 JAN-30 JAN 098/098/098 90 DAY MEAN 27 JAN 097 V. GEOMAGNETIC A INDICES OBSERVED AFR/AP 26 JAN 002/003 ESTIMATED AFR/AP 27 JAN 005/005 PREDICTED AFR/AP 28 JAN-30 JAN 005/005-020/015-015/020 VI. GEOMAGNETIC ACTIVITY PROBABILITIES 28 JAN-30 JAN A. MIDDLE LATITUDES ACTIVE 05/60/50 MINOR STORM 00/20/15 MAJOR-SEVERE STORM 00/11/05 B. HIGH LATITUDES ACTIVE 05/70/70 MINOR STORM 00/10/10 MAJOR-SEVERE STORM 00/10/10