Viewing archive of Saturday, 18 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 18 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 352 Issued at 2200Z on 18 DEC 1999IA. Analysis of Solar Active Regions and Activity from 17-2100Z to 18-2100Z SOLAR ACTIVITY HAS BEEN MODERATE. ACTIVE REGIONS 8798
(S13E09) AND 8806 (N19E62) HAVE PRODUCED FREQUENT MINOR FLARES
INCLUDING 2 WEAK CLASS M EVENTS IN THE LAST 24 HOURS. REGION 8806
AND NEWLY NUMBERED REGION 8807 (N11E68) ARE TWO ACTIVE REGIONS THAT
HAVE ROTATED INTO VIEW ON THE NORTHEAST LIMB.
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO BE
MODERATE WITH UP TO CLASS M EVENTS LIKELY FROM REGIONS 8798,8806,
AND 8807.
IIA. Geophysical Activity Summary 17-2100Z to 18-2100Z
GEOMAGNETIC ACTIVITY HAS DECLINED FROM UNSETTLED TO QUIET.
IIB. Geophysical Activity Forecast
GEOMAGNETIC ACTIVITY IS
EXPECTED TO BE INCREASING SLIGHTLY LATER IN THE FORECAST PERIOD AS A
SMALL CORONAL HOLE ROTATES INTO POSITION TO AFFECT EARTH.
III. Event Probabilities 19 DEC to 21 DEC
| Class M | 45% | 45% | 45% |
| Class X | 15% | 15% | 15% |
| Proton | 05% | 05% | 05% |
| PCAF | GREEN | ||
IV. Penticton 10.7 cm Flux
Observed 18 DEC 206 Predicted 19 DEC-21 DEC 205/200/195 90 Day Mean 18 DEC 170
V. Geomagnetic A Indices
OBSERVED AFR/AP 17 DEC 008/005 ESTIMATED AFR/AP 18 DEC 003/005 PREDICTED AFR/AP 19 DEC-21 DEC 007/008-008/015-006/012
VI. Geomagnetic Activity Probabilities 19 DEC to 21 DEC
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 05% | 09% | 07% |
| Minor storm | 02% | 02% | 05% |
| Major-severe storm | 01% | 01% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 06% | 12% | 10% |
| Minor storm | 03% | 03% | 06% |
| Major-severe storm | 01% | 01% | 01% |
All times in UTC
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