NOAA/USAF Report of Solar-Geophysical Activity 21 Apr 2000
: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
