Viewing archive of Thursday, 22 April 1999
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 1999 Apr 22 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 22 APR 1999IA. Analysis of Solar Active Regions and Activity from 21-2100Z to 22-2100Z SOLAR ACTIVITY WAS AT LOW LEVELS. A C4 X-RAY BURST
OCCURRED AT 22/0509Z AND WAS LIKELY ASSOCIATED WITH A CORONAL MASS
EJECTION OFF THE SW LIMB. REGION 8518 (S15E04) EXHIBITED MINOR
GROWTH WITH SEVERAL PLAGE FLUCTUATIONS NOTED LATE IN THE PERIOD.
REMAINING REGIONS WERE QUIET.
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO BE VERY
LOW TO LOW. REGION 8518 HAS POTENTIAL FOR C-CLASS ACTIVITY.
IIA. Geophysical Activity Summary 21-2100Z to 22-2100Z
THE GEOMAGNETIC FIELD WAS QUIET.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS
EXPECTED TO REMAIN QUIET.
III. Event Probabilities 23 APR to 25 APR
| Class M | 10% | 10% | 10% |
| Class X | 01% | 01% | 01% |
| Proton | 01% | 01% | 01% |
| PCAF | GREEN | ||
IV. Penticton 10.7 cm Flux
Observed 22 APR 100 Predicted 23 APR-25 APR 105/105/105 90 Day Mean 22 APR 130
V. Geomagnetic A Indices
OBSERVED AFR/AP 21 APR 009/012 ESTIMATED AFR/AP 22 APR 007/007 PREDICTED AFR/AP 23 APR-25 APR 007/007-007/007-010/010
VI. Geomagnetic Activity Probabilities 23 APR to 25 APR
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 10% | 10% | 15% |
| Minor storm | 05% | 05% | 05% |
| Major-severe storm | 01% | 01% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 15% | 15% | 20% |
| Minor storm | 05% | 05% | 05% |
| Major-severe storm | 01% | 01% | 01% |
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