NOAA/USAF Product: Report of Solar-Geophysical Activity 18 Apr 2000
:Product: Report of Solar-Geophysical Activity
:Issued: 2000 Apr 18 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 109 ISSUED AT 2200Z ON 18 APR 2000
IA. ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM 17/2100Z
TO 18/2100Z: SOLAR ACTIVITY WAS LOW. REGION 8963 (N16E09) RAPIDLY
EMERGED AS THE PRIMARY FLARE PRODUCING REGION ON THE VISIBLE DISK
AND WAS RESPONSIBLE FOR THE THREE LARGEST EVENTS OF THE PERIOD. THE
FIRST AND LARGEST EVENT WAS A C7/SF AT 18/0805UT, FOLLOWED BY A C4
FLARE WITH A TYPE II SWEEP AT 18/1153UT, AND FINALLY A C4/SF AT
18/1415UT. ALL EVENTS WERE ACCOMPANIED BY MINOR CENTIMETRIC BURSTS.
THIS REGION, THOUGH QUITE ACTIVE, IS A RELATIVELY SMALL DAO GROUP
WITH 80 MILLIONTHS OF WHITE LIGHT AREA. REGION 8955 (S22W19) HAS
STABILIZED, PRODUCING ONLY OCCASIONAL MINOR C-CLASS FLARES. NEW
REGION 8966 (S13E65) WAS NUMBERED TODAY. REMAINING REGIONS WERE
QUIET.
IB. SOLAR ACTIVITY FORECAST: SOLAR ACTIVITY IS EXPECTED TO BE LOW.
REGIONS 8955 AND 8963 WILL LIKELY CONTINUE TO PRODUCE C-CLASS
ACTIVITY.
IIA. GEOPHYSICAL ACTIVITY SUMMARY FROM 17/2100Z TO 18/2100Z:
THE GEOMAGNETIC FIELD WAS MOSTLY QUIET WITH OCCASIONAL UNSETTLED
PERIODS.
IIB. GEOPHYSICAL ACTIVITY FORECAST: THE GEOMAGNETIC FIELD IS
EXPECTED TO REMAIN AT QUIET TO UNSETTLED LEVELS.
III. EVENT PROBABILITIES 19 APR-21 APR
CLASS M 35/35/35
CLASS X 05/05/05
PROTON 01/01/01
PCAF GREEN
IV. PENTICTON 10.7 CM FLUX
OBSERVED 18 APR 160
PREDICTED 19 APR-21 APR 160/165/170
90 DAY MEAN 18 APR 183
V. GEOMAGNETIC A INDICES
OBSERVED AFR/AP 17 APR 011/014
ESTIMATED AFR/AP 18 APR 006/010
PREDICTED AFR/AP 19 APR-21 APR 008/012-010/015-005/008
VI. GEOMAGNETIC ACTIVITY PROBABILITIES 19 APR-21 APR
A. MIDDLE LATITUDES
ACTIVE 25/25/20
MINOR STORM 10/10/05
MAJOR-SEVERE STORM 01/01/01
B. HIGH LATITUDES
ACTIVE 30/35/25
MINOR STORM 20/25/15
MAJOR-SEVERE STORM 05/05/01
