Viewing archive of Friday, 16 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 16 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 106 Issued at 2200Z on 16 APR 1999IA. Analysis of Solar Active Regions and Activity from 15-2100Z to 16-2100Z SOLAR ACTIVITY WAS VERY LOW. A NEW REGION WAS NUMBERED
TODAY AS REGION 8517 (N20W21).
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO BE VERY
LOW TO LOW THROUGH THE FORECAST PERIOD.
IIA. Geophysical Activity Summary 15-2100Z to 16-2100Z
THE GEOMAGNETIC FIELD WAS QUIET TO ACTIVE. AT 16/1036Z A SHOCK
ARRIVED AT L1. A SUDDEN IMPULSE OCCURRED AT 16/1126Z. THE SOLAR WIND
DENSITY OFF OF THE ACE SPACECRAFT INCREASED TO 68 P/CC AT 16/1443Z.
SEVERAL MAGNETOPAUSE CROSSINGS WERE OBSERVED ON THE GOES-8 (W74)
BETWEEN 16/1515-1820Z. THIS ACTIVITY CORRELATES WELL WITH THE
CORONAL MASS EJECTION OBSERVED ON 13 APRIL.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS
EXPECTED TO BE UNSETTLED TO ACTIVE THE FIRST DAY OF THE FORECAST
WITH PERIODS OF MINOR STORM CONDITIONS POSSIBLE. THIS ACTIVITY IS
ANTICIPATED DUE TO THE CME OBSERVED ON 13 APRIL. THE REMAINDER OF
THE PERIOD IS EXPECTED TO BE QUIET TO UNSETTLED.
III. Event Probabilities 17 APR to 19 APR
| Class M | 15% | 15% | 15% |
| Class X | 01% | 01% | 01% |
| Proton | 01% | 01% | 01% |
| PCAF | GREEN | ||
IV. Penticton 10.7 cm Flux
Observed 16 APR 123 Predicted 17 APR-19 APR 120/118/116 90 Day Mean 16 APR 135
V. Geomagnetic A Indices
OBSERVED AFR/AP 15 APR 002/004 ESTIMATED AFR/AP 16 APR 010/015 PREDICTED AFR/AP 17 APR-19 APR 020/020-010/010-005/015
VI. Geomagnetic Activity Probabilities 17 APR to 19 APR
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 30% | 20% | 15% |
| Minor storm | 20% | 10% | 05% |
| Major-severe storm | 10% | 05% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 35% | 25% | 20% |
| Minor storm | 25% | 15% | 10% |
| Major-severe storm | 15% | 10% | 05% |
All times in UTC
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