Press Release

NOAA/USAF Report of Solar-Geophysical Activity 24 Apr 2000

By SpaceRef Editor
April 24, 2000
Filed under

:Product: Report of Solar-Geophysical Activity
:Issued: 2000 Apr 24 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 115 ISSUED AT 2200Z ON 24 APR 2000
IA. ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM 23/2100Z
TO 24/2100Z: SOLAR ACTIVITY WAS LOW. OCCASIONAL C-CLASS FLARES
OCCURRED, PRIMARILY FROM REGIONS 8971 (N18E28) AND 8972 (N34W34).
REGION 8971 IS A LARGE, COMPLEX GROUP, AND 8972 HAS A DEGREE OF
MAGNETIC COMPLEXITY AS WELL. REGION 8970 (S15E30), THE LARGEST ON
THE DISK AT OVER 1000 MILLIONTHS, HAS BEEN QUIET.
IB. SOLAR ACTIVITY FORECAST: SOLAR ACTIVITY IS EXPECTED TO BE LOW
TO MODERATE. REGIONS 8970, 8971, AND 8972 ALL HAVE THE POTENTIAL FOR
M-CLASS ACTIVITY.
IIA. GEOPHYSICAL ACTIVITY SUMMARY FROM 23/2100Z TO 24/2100Z:
THE GEOMAGNETIC FIELD WAS AT QUIET TO MINOR STORM LEVELS. A TRANSIENT
WAS SEEN TO PASS THE ACE SPACECRAFT AROUND 0400Z, BRINGING WITH IT
ENHANCED SOLAR WIND PARAMETERS. ACTIVE TO MINOR STORM CONDITIONS
OCCURRED SHORTLY THEREAFTER, THEN SUBSIDING TO MORE NORMAL (BUT
SLIGHTLY ENHANCED) LEVELS BY THE END OF THE PERIOD.
IIB. GEOPHYSICAL ACTIVITY FORECAST: THE GEOMAGNETIC FIELD IS
EXPECTED TO BE UNSETTLED TO ACTIVE ON 25 APRIL, AND STRICTLY
UNSETTLED THE LAST TWO DAYS OF THE INTERVAL.
III. EVENT PROBABILITIES 25 APR-27 APR
CLASS M 50/50/50
CLASS X 01/01/01
PROTON 01/01/01
PCAF GREEN
IV. PENTICTON 10.7 CM FLUX
OBSERVED 24 APR 206
PREDICTED 25 APR-27 APR 210/210/215
90 DAY MEAN 24 APR 186
V. GEOMAGNETIC A INDICES
OBSERVED AFR/AP 23 APR 004/008
ESTIMATED AFR/AP 24 APR 015/025
PREDICTED AFR/AP 25 APR-27 APR 015/018-010/015-010/012
VI. GEOMAGNETIC ACTIVITY PROBABILITIES 25 APR-27 APR
A. MIDDLE LATITUDES
ACTIVE 40/20/20
MINOR STORM 10/05/05
MAJOR-SEVERE STORM 01/01/01
B. HIGH LATITUDES
ACTIVE 50/30/30
MINOR STORM 10/05/05
MAJOR-SEVERE STORM 01/01/01

SpaceRef staff editor.