Viewing archive of Monday, 27 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 27 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 361 Issued at 2200Z on 27 DEC 1999IA. Analysis of Solar Active Regions and Activity from 26-2100Z to 27-2100Z SOLAR ACTIVITY WAS MODERATE. REGION 8806 (N20W53)
PRODUCED TWO SMALL M FLARES, AN M1/SF AT 27/0146UT AND AN M2/SN AT
27/1154UT. THIS MAGNETICALLY COMPLEX REGION IS SLOWLY DECLINING AS
IT APPROACHES WEST LIMB. ONLY MINOR ACTIVITY WAS OBSERVED FROM THE
REMAINING THREE SPOTTED REGIONS. THE PROMINENCE ON THE EAST LIMB
NEAR N40 IS IN THE PROCESS OF ERUPTING. SOLAR X-RAY AND RADIO
BACKGROUND FLUX ARE DROPPING.
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO BE LOW
TO MODERATE. THERE IS A CHANCE FOR MAJOR FLARES UNTIL AFTER REGION
8806 ROTATES OFF THE DISK ON 31 DEC.
IIA. Geophysical Activity Summary 26-2100Z to 27-2100Z
THE GEOMAGNETIC FIELD HAS BEEN QUIET TO UNSETTLED. A SHOCK WAS
OBSERVED AT THE ACE SPACECRAFT AT 26/2126UT RESULTING IN A MINOR
INCREASE IN ACTIVITY AT THE EARTH AFTER 26/2230UT.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS
EXPECTED TO BE MOSTLY QUIET.
III. Event Probabilities 28 DEC to 30 DEC
| Class M | 50% | 50% | 50% |
| Class X | 10% | 10% | 10% |
| Proton | 10% | 10% | 10% |
| PCAF | GREEN | ||
IV. Penticton 10.7 cm Flux
Observed 27 DEC 162 Predicted 28 DEC-30 DEC 160/155/150 90 Day Mean 27 DEC 176
V. Geomagnetic A Indices
OBSERVED AFR/AP 26 DEC 002/002 ESTIMATED AFR/AP 27 DEC 005/006 PREDICTED AFR/AP 28 DEC-30 DEC 005/005-005/005-008/010
VI. Geomagnetic Activity Probabilities 28 DEC to 30 DEC
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 10% | 10% | 15% |
| Minor storm | 05% | 05% | 05% |
| Major-severe storm | 01% | 01% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 15% | 15% | 20% |
| Minor storm | 10% | 10% | 10% |
| Major-severe storm | 01% | 01% | 01% |
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