Press Release

NOAA/USAF Product: Report of Solar-Geophysical Activity 20 Apr 2000

By SpaceRef Editor
April 20, 2000
Filed under

:Product: Report of Solar-Geophysical Activity
:Issued: 2000 Apr 20 2200 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 111 ISSUED AT 2200Z ON 20 APR 2000
IA. ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM 19/2100Z
TO 20/2100Z: SOLAR ACTIVITY WAS LOW. NEW REGION 8969 (N13E62)
PRODUCED THE LARGEST FLARE OF THE DAY, A C8/SF AT 20/1033UT. REGION
8963 (N16W18) ALSO PRODUCED C-CLASS ACTIVITY, THE LARGEST BEING A
C4/SF AT 20/1937UT. NEW REGION 8970 (S14E77) IS ROTATING AROUND THE
EAST LIMB. SO FAR A LARGE H-TYPE SPOT IS VISIBLE AND TRAILER SPOTS
ARE EXPECTED TO APPEAR BY TOMORROW.
IB. SOLAR ACTIVITY FORECAST: SOLAR ACTIVITY IS EXPECTED TO BE LOW
TO MODERATE. C-CLASS ACTIVITY IS EXPECTED TO CONTINUE IN REGION
8963. AN ISOLATED M-CLASS FLARE IS ALSO POSSIBLE.
IIA. GEOPHYSICAL ACTIVITY SUMMARY FROM 19/2100Z TO 20/2100Z:
THE GEOMAGNETIC FIELD WAS QUIET TO ACTIVE.
IIB. GEOPHYSICAL ACTIVITY FORECAST: THE GEOMAGNETIC FIELD IS
EXPECTED TO BE PREDOMINATELY QUIET TO UNSETTLED WITH THE POSSIBILITY
OF ISOLATED ACTIVE PERIODS.
III. EVENT PROBABILITIES 21 APR-23 APR
CLASS M 40/40/40
CLASS X 01/01/01
PROTON 01/01/01
PCAF GREEN
IV. PENTICTON 10.7 CM FLUX
OBSERVED 20 APR 181
PREDICTED 21 APR-23 APR 185/190/200
90 DAY MEAN 20 APR 183
V. GEOMAGNETIC A INDICES
OBSERVED AFR/AP 19 APR 009/012
ESTIMATED AFR/AP 20 APR 018/015
PREDICTED AFR/AP 21 APR-23 APR 015/012-010/005-010/005
VI. GEOMAGNETIC ACTIVITY PROBABILITIES 21 APR-23 APR
A. MIDDLE LATITUDES
ACTIVE 15/15/15
MINOR STORM 15/10/10
MAJOR-SEVERE STORM 05/02/02
B. HIGH LATITUDES
ACTIVE 15/15/15
MINOR STORM 15/10/10
MAJOR-SEVERE STORM 05/05/05

SpaceRef staff editor.