Viewing archive of Friday, 31 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 31 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 365 Issued at 2200Z on 31 DEC 1999IA. Analysis of Solar Active Regions and Activity from 30-2100Z to 31-2100Z SOLAR ACTIVITY WAS LOW. THE LARGEST EVENT THIS PERIOD
WAS A C2/SF FROM NEWLY NUMBERED REGION 8815 (N10E61). THIS REGION
EMERGED AS A SMALL, COMPACT C-CLASS SPOT GROUP. REMAINING REGIONS
WERE QUIET.
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO REMAIN
AT LOW LEVELS. ISOLATED LOW LEVEL C-CLASS FLARES ARE LIKELY.
IIA. Geophysical Activity Summary 30-2100Z to 31-2100Z
THE GEOMAGNETIC FIELD WAS UNSETTLED TO ACTIVE. EFFECTS FROM A
CORONAL HOLE, HIGH SPEED SOLAR WIND STREAM THAT BEGAN YESTERDAY,
CONTINUED TODAY.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD WILL
CONTINUE AT UNSETTLED TO ACTIVE LEVELS. A LARGE, GEOEFFECTIVELY
POSITIONED CORONAL HOLE WILL PROLONG THE CURRENT DISTURBANCE THROUGH
DAY THREE.
III. Event Probabilities 01 JAN to 03 JAN
| Class M | 10% | 10% | 10% |
| Class X | 05% | 05% | 05% |
| Proton | 05% | 05% | 05% |
| PCAF | GREEN | ||
IV. Penticton 10.7 cm Flux
Observed 31 DEC 130 Predicted 01 JAN-03 JAN 130/130/130 90 Day Mean 31 DEC 176
V. Geomagnetic A Indices
OBSERVED AFR/AP 30 DEC 007/008 ESTIMATED AFR/AP 31 DEC 020/021 PREDICTED AFR/AP 01 JAN-03 JAN 020/025-020/025-015/018
VI. Geomagnetic Activity Probabilities 01 JAN to 03 JAN
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 65% | 65% | 50% |
| Minor storm | 25% | 25% | 15% |
| Major-severe storm | 10% | 10% | 05% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 60% | 60% | 50% |
| Minor storm | 30% | 30% | 20% |
| Major-severe storm | 10% | 10% | 05% |
All times in UTC
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