Viewing archive of Thursday, 17 June 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 Jun 17 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 168 Issued at 2200Z on 17 JUN 1999IA. Analysis of Solar Active Regions and Activity from 16-2100Z to 17-2100Z SOLAR ACTIVITY BECAME MODERATE. DEPARTED REGION 8569
(N18W98) PRODUCED AN M3 AT 17/1730Z. THE BIG BEAR OBSERVATORY
PROVIDED CONFIRMATION OF THE SOURCE REGION. A TYPE II WITH VELOCITY
NEAR 600 KM/S AND MINOR CENTIMETRIC BURSTS ACCOMPANIED THIS EVENT.
THE MAUNA LOA GROUND-BASED CORONAGRAPH OBSERVED A FAINT CORONAL MASS
EJECTION WITH THIS EVENT. REGION 8569 ALSO PRODUCED A C5 WITH AN
ERUPTIVE PROMINENCE AT 17/0036Z. SMALL REGIONS 8590 (S21W14) AND
8591 (N12E15) EMERGED ON THE DISK. REGION 8590 EMERGED SLIGHTLY
AHEAD OF EXISTING REGION 8588 (S22W05).
IB. Solar Activity Forecast
SOLAR ACTIVITY SHOULD BE GENERALLY LOW
FOR THE NEXT THREE DAYS. THERE IS A SLIGHT POSSIBILITY OF AN M-CLASS
EVENT DURING THAT PERIOD FROM CURRENT DISK REGIONS AND PREVIOUSLY
ACTIVE REGIONS DUE TO ROTATE OVER THE NORTHEAST LIMB. DEPARTED
REGION 8569 WILL BECOME LESS OF A THREAT AS IT ROTATES FARTHER
BEYOND THE WEST LIMB.
IIA. Geophysical Activity Summary 16-2100Z to 17-2100Z
THE GEOMAGNETIC FIELD WAS QUIET TO SLIGHTLY UNSETTLED.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD SHOULD BE
QUIET TO UNSETTLED FOR THE NEXT THREE DAYS.
III. Event Probabilities 18 JUN to 20 JUN
| Class M | 15% | 15% | 15% |
| Class X | 05% | 05% | 05% |
| Proton | 05% | 05% | 05% |
| PCAF | GREEN | ||
IV. Penticton 10.7 cm Flux
Observed 17 JUN 147 Predicted 18 JUN-20 JUN 150/152/154 90 Day Mean 17 JUN 136
V. Geomagnetic A Indices
OBSERVED AFR/AP 16 JUN 005/007 ESTIMATED AFR/AP 17 JUN 005/010 PREDICTED AFR/AP 18 JUN-20 JUN 007/008-010/012-007/010
VI. Geomagnetic Activity Probabilities 18 JUN to 20 JUN
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 05% | 10% | 05% |
| Minor storm | 01% | 05% | 05% |
| Major-severe storm | 01% | 01% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 10% | 20% | 10% |
| Minor storm | 05% | 10% | 05% |
| Major-severe storm | 01% | 05% | 01% |
All times in UTC
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