:Product: Report of Solar-Geophysical Activity
:Issued: 2000 Apr 21 2210 UT
# 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 112 ISSUED AT 2200Z ON 21 APR 2000
IA.  ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM  20/2100Z
TO 21/2100Z:  SOLAR ACTIVITY WAS LOW. REGION 8963 (N16W31) PRODUCED
SEVERAL SMALL C-CLASS FLARES. THE LARGEST WAS A C2/SF AT 21/0059UT.
THIS REGION APPEARS TO BE DECAYING SLOWLY. REGION 8970 (S15E68)
PRODUCED THE LARGEST FLARE OF THE DAY, A C4/SF AT 21/1758UT. TRAILER
SUNSPOTS HAVE ROTATED INTO VIEW MAKING THIS REGION A
MODERATELY-SIZED E-TYPE GROUP. NEW REGION 8971 (N18E67) ROTATED
AROUND THE EAST LIMB AND NEW REGION 8972 (N32E03) EMERGED ON THE
DISK.
IB.  SOLAR ACTIVITY FORECAST:  SOLAR ACTIVITY IS EXPECTED TO BE LOW
TO MODERATE. C-CLASS ACTIVITY IS POSSIBLE FROM A NUMBER OF REGIONS,
INCLUDING 8955 (S21W58), 8963 (N16W31), 8968 (S12E01), 8970
(S15E68), AND 8971 (N18E67).  AN ISOLATED M-CLASS FLARE IS ALSO
POSSIBLE.
IIA.  GEOPHYSICAL ACTIVITY SUMMARY FROM 20/2100Z TO 21/2100Z:
THE GEOMAGNETIC FIELD WAS QUIET TO ACTIVE.
IIB.  GEOPHYSICAL ACTIVITY FORECAST:  THE GEOMAGNETIC FIELD IS
EXPECTED TO BE QUIET TO ACTIVE.
III.  EVENT PROBABILITIES 22 APR-24 APR
CLASS M    40/40/40
CLASS X    01/01/01
PROTON     01/01/01
PCAF       GREEN
IV.  PENTICTON 10.7 CM FLUX
OBSERVED           21 APR 187
PREDICTED   22 APR-24 APR  190/200/205
90 DAY MEAN        21 APR 184
V.  GEOMAGNETIC A INDICES
OBSERVED AFR/AP 20 APR  018/014
ESTIMATED AFR/AP 21 APR  010/012
PREDICTED AFR/AP 22 APR-24 APR  010/008-010/005-010/005
VI.  GEOMAGNETIC ACTIVITY PROBABILITIES 22 APR-24 APR
A.  MIDDLE LATITUDES
ACTIVE                15/15/15
MINOR STORM           01/01/01
MAJOR-SEVERE STORM    01/01/01
B.  HIGH LATITUDES
ACTIVE                15/15/15
MINOR STORM           05/05/05
MAJOR-SEVERE STORM    01/01/01