:Product: 19991010RSGA.txt :Issued: 1999 Oct 10 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 283 ISSUED AT 2200Z ON 10 OCT 1999 IA. ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM 09/2100Z TO 10/2100Z: SOLAR ACTIVITY WAS LOW. THREE SMALL C-CLASS SUBFLARES OCCURRED DURING THE PERIOD. TWO HAD NO OPTICAL CORRELATION AND ONE C2/SF AT 10/1356Z FROM REGION 8728 (N22E50). OF THE THIRTEEN SPOTTED REGIONS ON THE SOLAR DISK AT THIS TIME, NONE ARE VERY DYNAMIC IN MAGNETIC STRUCTURE. A REGION OF INTEREST IS REGION 8729 (N12E58). THIS REGION MAY CONSIST OF TWO OR MORE REGIONS ONCE THE AREA ROTATES FURTHER ONTO THE DISK FOR A BETTER ANALYSIS. IB. SOLAR ACTIVITY FORECAST: SOLAR ACTIVITY IS EXPECTED TO REMAIN LOW THROUGH THE PERIOD. SEVERAL OF THE EXISTING REGIONS HAVE C-CLASS FLARE POTENTIAL WITH A SMALL CHANCE OF AN ISOLATED M-CLASS EVENT. IIA. GEOPHYSICAL ACTIVITY SUMMARY FROM 09/2100Z TO 10/2100Z: THE GEOMAGNETIC FIELD WAS AT QUIET TO MINOR STORM CONDITIONS THROUGH THE PERIOD. THIS DISTURBANCE IS LIKELY ASSOCIATED WITH A HIGH-SPEED CORONAL HOLE WIND STREAM. IIB. GEOPHYSICAL ACTIVITY FORECAST: THE GEOMAGNETIC FIELD IS EXPECTED TO BE AT ACTIVE TO MINOR STORM LEVELS THROUGH THE FORECAST PERIOD AS CORONAL HOLE EFFECTS CONTINUE. III. EVENT PROBABILITIES 11 OCT-13 OCT CLASS M 20/20/20 CLASS X 01/01/01 PROTON 01/01/01 PCAF GREEN IV. PENTICTON 10.7 CM FLUX OBSERVED 10 OCT 161 PREDICTED 11 OCT-13 OCT 165/168/170 90 DAY MEAN 10 OCT 154 V. GEOMAGNETIC A INDICES OBSERVED AFR/AP 09 OCT 004/006 ESTIMATED AFR/AP 10 OCT 025/030 PREDICTED AFR/AP 11 OCT-13 OCT 020/030-020/030-015/035 VI. GEOMAGNETIC ACTIVITY PROBABILITIES 11 OCT-13 OCT A. MIDDLE LATITUDES ACTIVE 50/50/25 MINOR STORM 30/30/15 MAJOR-SEVERE STORM 10/10/05 B. HIGH LATITUDES ACTIVE 60/60/60 MINOR STORM 30/30/30 MAJOR-SEVERE STORM 10/10/10