Viewing archive of Monday, 18 October 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 Oct 18 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 291 Issued at 2200Z on 18 OCT 1999IA. Analysis of Solar Active Regions and Activity from 17-2100Z to 18-2100Z
SOLAR ACTIVITY CONTINUED AT LOW LEVELS. REGION 8731
(N13W33) SHOWED A SMALL INCREASE IN SPOT COUNT AND REMAINED A LARGE,
MAGNETICALLY COMPLEX REGION. IT PRODUCED ISOLATED C-CLASS SUBFLARES
DURING THE PERIOD. NO SIGNIFICANT CHANGES WERE OBSERVED IN THE
REMAINING REGIONS AND NO NEW REGIONS WERE ASSIGNED.
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO BE AT
LOW TO MODERATE LEVELS. REGION 8731, THOUGH RELATIVELY INACTIVE
DURING THE PAST FEW DAYS, STILL APPEARS CAPABLE OF M-CLASS FLARE
PRODUCTION. THERE IS A SLIGHT CHANCE FOR A MAJOR FLARE FROM THIS
REGION AS WELL.
IIA. Geophysical Activity Summary 17-2100Z to 18-2100Z
GEOMAGNETIC FIELD ACTIVITY WAS AT QUIET TO UNSETTLED LEVELS. THE
GREATER THAN 2 MEV ELECTRON FLUX REMAINED AT MODERATE TO HIGH
LEVELS.
IIB. Geophysical Activity Forecast
GEOMAGNETIC FIELD ACTIVITY IS
EXPECTED TO REMAIN AT QUIET TO UNSETTLED LEVELS DURING THE FIRST TWO
DAYS OF THE PERIOD. ACTIVITY IS EXPECTED TO INCREASE TO UNSETTLED TO
ACTIVE LEVELS ON THE FINAL DAY DUE TO CORONAL HOLE EFFECTS. THE
GREATER THAN 2 MEV ELECTRON FLUX IS EXPECTED TO REMAIN AT MODERATE
TO HIGH LEVELS.
III. Event Probabilities 19 OCT to 21 OCT
| Class M | 50% | 50% | 50% |
| Class X | 10% | 10% | 10% |
| Proton | 10% | 10% | 10% |
| PCAF | GREEN | ||
IV. Penticton 10.7 cm Flux
Observed 18 OCT 173 Predicted 19 OCT-21 OCT 170/170/165 90 Day Mean 18 OCT 158
V. Geomagnetic A Indices
OBSERVED AFR/AP 17 OCT 016/026 ESTIMATED AFR/AP 18 OCT 008/012 PREDICTED AFR/AP 19 OCT-21 OCT 008/010-010/008-015/015
VI. Geomagnetic Activity Probabilities 19 OCT to 21 OCT
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 10% | 20% | 30% |
| Minor storm | 05% | 10% | 15% |
| Major-severe storm | 01% | 01% | 05% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 15% | 25% | 40% |
| Minor storm | 05% | 15% | 20% |
| Major-severe storm | 01% | 01% | 10% |
All times in UTC
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