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 UTC
Prepared 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 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 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 M40%40%40%
Class X01%01%01%
Proton01%01%01%
PCAFGREEN
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
Active15%15%15%
Minor storm01%01%01%
Major-severe storm01%01%01%
B. High Latitudes
Active15%15%15%
Minor storm05%05%05%
Major-severe storm01%01%01%

All times in UTC

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