Viewing archive of Monday, 20 December 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 Dec 20 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 354 Issued at 2200Z on 20 DEC 1999IA. Analysis of Solar Active Regions and Activity from 19-2100Z to 20-2100Z SOLAR ACTIVITY HAS BEEN LOW. SOLAR X-RAY BACKGROUND IS
RUNNING NEAR THE C LEVEL, RESULTING IN NUMEROUS SMALL C CLASS
EVENTS. THERE ARE TWO MAJOR COMPLEXES CURRENTLY VISIBLE, REGION
8798 (S12 W20) AND REGION 8806 (N18E37). BOTH THESE REGIONS ARE
MAGNETICALLY COMPLEX, WITH DELTAS, HOWEVER, ONLY MINOR PLAGE
ENHANCEMENTS ARE BEING OBSERVED. SMALL REGION 8803 (S12W30) IS
EMBEDDED IN THE LEADING POLARITY PLAGE OF REGION 8798. REGION 8807
(N10 E43) IS LOCATED IN AN OLD PLAGE JUST SOUTH OF REGION 8806.
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO BE LOW
TO MODERATE, HOWEVER, MAJOR FLARES ARE POSSIBLE FROM REGIONS 8798
(S12W20) AND 8806 (N18E37).
IIA. Geophysical Activity Summary 19-2100Z to 20-2100Z
THE GEOMAGNETIC FIELD HAS BEEN BASICALLY QUIET.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS
EXPECTED TO BE QUIET TO UNSETTLED. THERE IS AN INCREASING CHANCE
FOR AN ENERGETIC PARTICLE EVENT FROM EITHER THE REGION 8798 OR
REGION 8806 COMPLEXES NOW VISIBLE.
III. Event Probabilities 21 DEC to 23 DEC
| Class M | 50% | 50% | 50% |
| Class X | 15% | 20% | 20% |
| Proton | 05% | 05% | 10% |
| PCAF | GREEN | ||
IV. Penticton 10.7 cm Flux
Observed 20 DEC 209 Predicted 21 DEC-23 DEC 205/200/195 90 Day Mean 20 DEC 171
V. Geomagnetic A Indices
OBSERVED AFR/AP 19 DEC 006/004 ESTIMATED AFR/AP 20 DEC 003/003 PREDICTED AFR/AP 21 DEC-23 DEC 008/012-010/012-007/010
VI. Geomagnetic Activity Probabilities 21 DEC to 23 DEC
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 25% | 25% | 10% |
| Minor storm | 10% | 10% | 01% |
| Major-severe storm | 01% | 01% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 25% | 25% | 15% |
| Minor storm | 10% | 10% | 01% |
| Major-severe storm | 01% | 01% | 01% |
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