Viewing archive of Friday, 21 April 2000
Solar activity report
Any mentioned solar flare in this report has a scaling factor applied by the Space Weather Prediction Center (SWPC). Because of the SWPC scaling factor, solar flares are reported as 42% smaller than for the science quality data. The scaling factor has been removed from our archived solar flare data to reflect the true physical units.
Report of Solar-Geophysical Activity 2000 Apr 21 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 112 Issued at 2200Z on 21 APR 2000IA. 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 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 to 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 to 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% |
All times in UTC
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