:Product: 19990418RSGA.txt
:Issued: 1999 Apr 18 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 108 ISSUED AT 2200Z ON 18 APR 1999
IA.  ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM  17/2100Z
TO 18/2100Z:  SOLAR ACTIVITY REMAINED AT VERY LOW LEVELS. ISOLATED
B-CLASS X-RAY FLARES OCCURRED, TWO OF WHICH WERE OPTICALLY TIED TO
REGION 8514 (S33W69). THIS REGION SHOWED GRADUAL DECAY AS IT
APPROACHED THE WEST LIMB. ALL THE REMAINING REGIONS WERE EITHER
STABLE OR DECLINING SLOWLY. A 21-DEGREE FILAMENT, LAST SEEN CENTERED
NEAR N19E03, DISAPPEARED EARLY IN THE PERIOD. A PARTIAL-HALO CME WAS
OBSERVED AROUND 17/0600Z. NO NEW REGIONS WERE ASSIGNED.
IB.  SOLAR ACTIVITY FORECAST:  SOLAR ACTIVITY IS EXPECTED TO REMAIN
AT VERY LOW LEVELS.
IIA.  GEOPHYSICAL ACTIVITY SUMMARY FROM 17/2100Z TO 18/2100Z:
THE GEOMAGNETIC FIELD WAS MOSTLY QUIET WITH BRIEF UNSETTLED INTERVALS
AT ALL LATITUDES.
IIB.  GEOPHYSICAL ACTIVITY FORECAST:  THE GEOMAGNETIC FIELD IS
EXPECTED TO BE AT QUIET TO UNSETTLED LEVELS DURING THE FIRST TWO
DAYS, THEN INCREASE TO ACTIVE LEVELS ON THE THIRD DAY IN RESPONSE TO
THE CME MENTIONED ABOVE.
III.  EVENT PROBABILITIES 19 APR-21 APR
CLASS M    10/10/10
CLASS X    01/01/01
PROTON     01/01/01
PCAF       GREEN
IV.  PENTICTON 10.7 CM FLUX
OBSERVED           18 APR 113
PREDICTED   19 APR-21 APR  110/110/110
90 DAY MEAN        18 APR 134
V.  GEOMAGNETIC A INDICES
OBSERVED AFR/AP 17 APR  030/047
ESTIMATED AFR/AP 18 APR  008/010
PREDICTED AFR/AP 19 APR-21 APR  005/008-010/012-020/015
VI.  GEOMAGNETIC ACTIVITY PROBABILITIES 19 APR-21 APR
A.  MIDDLE LATITUDES
ACTIVE                10/15/50
MINOR STORM           05/05/10
MAJOR-SEVERE STORM    01/01/05
B.  HIGH LATITUDES
ACTIVE                15/20/50
MINOR STORM           10/10/20
MAJOR-SEVERE STORM    01/01/05